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It has been several months since we have shared any progress updates on our powertrain development work and in particular how the “powertrain 1.5” program is progressing for the Roadster.
For those of you not thinking about this every day like we are 
the powertrain 1.5 is an improved motor, inverter and gearbox designed to replace our previous two-speed transmission that had many durability, efficiency and cost challenges. We officially kicked off this program just last fall but it is something that Elon and I had discussed several years ago. A very low-cost and efficient single-speed gearbox mated with a continually improving motor, inverter and battery is the core competency of Tesla’s powertrain team and it is also our roadmap for future vehicles.
Many people are now working very hard on this project and I’m happy to report that we are holding our initial schedule for production deployment around vehicle #41 later this year. Several significant milestones have been passed in each of the key components that I will discuss in more detail below.
We also have a Roadster with a prototype 1.5 powertrain that we are now driving regularly. The higher torque is really phenomenal. I have many hours behind the wheel of the 1.0 powertrain and this is simply much better. The motor torque is improved by a bit more than 30% beyond what was already great and the ¼ mile time for the car is now in the 12.9 second range. The top speed of the vehicle remains over 120 mph.
Here is a quick refresher on what the powertrain 1.5 is and is not:
- An improved inverter (PEM) to deliver higher motor current
- An improved motor to handle higher current and torque
- A new single-speed gearbox
- A new motor to gearbox coupler and an improved motor cable
- Upgraded vehicle firmware
- NO changes to the battery pack
Power Electronics Module (PEM) Update
It is counterintuitive that one of the most diminutive parts in the powertrain is actually responsible for most of the performance improvement between 1.0 and 1.5. The IGBT (Insulated Gate Bipolar Transistor) inside of the PEM is what converts and regulates power from the battery. These small parts are improving in both efficiency and power handling capability and by integrating the latest generation of parts, we have been able to boost the PEM output current by about 33% from 640A rms to 850A rms with the same number of IGBTs.
We could have increased the current and torque by just using more of the older IGBTs but this would have required a much more extensive redesign of the entire PEM including the mechanical packaging and cooling systems.
Since the new IGBTs have improved efficiency they also end up giving the PEM better overall efficiency and improve the range of the vehicle slightly. At most operating points the PEM is already very efficient (95-98%) but every little bit helps. Other than this change to the IBGTs and a few improved internal cables the PEM is identical to a 1.0 PEM; without the external serial number labels you can not tell them apart.
Motor Update
The 1.5 motor has slightly more substantial changes to deal with the higher current. We have modified the castings on both ends of the motor called “endbells.” These were modified to allow for a different interface to the new gearbox and also to improve the durability of the fastening between the motor and transmission. We also modified the motor shaft slightly with a larger and stronger output spline to handle the higher torque that the motor can generate at 850A. The bearings remain the same and the internal electromagnetic design of the motor is identical. The same number of turns and lamination geometry are used.
One additional improvement was made to the motor terminal lugs in order to significantly reduce their resistance yielding better efficiency and much less temperature rise at very high currents. Connected to these lugs is the motor cable that attaches the PEM to the motor. We have also reduced the resistance of this motor cable by changing wire material from copper clad aluminum to pure copper. This increases the mass slightly but also improves the efficiency and reduces temperature rise.
Below on the right is a prototype 1.5 motor that is now being tested on the dynamometer at our shop in San Carlos. On the left is a plastic SLA model that we made of the new endbells before the metal parts were ready.
Gearbox Update
The new gearbox is the most significant change from powertrain 1.0 to 1.5. We have significantly reduced the complexity of this gearbox by getting rid of the need for shifting or speed matching between two gear sets. There is only one set of gears that is always engaged with a ratio of (8.2752:1). There are no clutches and we have also done away with the need for an electric oil pump and instead integrated a very efficient gear-driven oil pump into the gearbox. All of these simplifications have saved a great deal of mass and the new gearbox is approximately 45kg instead of 53kg for the old two-speed design.
This mass savings is even more impressive when you consider that we have designed this transmission to have a long life at a much higher input torque (400 Nm) and higher speed (14,000 rpm).
The engineering design of this new gearbox has been finished for over a month and we are now running prototypes through their paces on dynamometers. We built two initial gearboxes with machined aluminum housings so we could gain some early test results before finalizing the cast housing tooling and machining fixtures.
One of the most exciting features of this new gearbox (from an EV perspective) that we have been able to validate on the first prototypes is that it has extremely low spinning drag (less than 0.1 Nm of dry drag torque.) This is less than any other gearbox we have tested with the only possible exception being the EV1 gearbox. This low drag contributes to the 1.5 powertrain having a slightly improved range figure.
The two pictures below show some of the gears and shafts. On the left is the input shaft assembly…spinning up to 14,000 rpm bearing selection is very important. The spline on the right connects to the motor coupling. The picture on the right is the intermediate shaft assembly. Notice the transmission locking “gear” in the center that engages with a stationary pawl when the car is parked.
These are all of the gears and shafts assembled in one case half. The blue automatic transmission fluid (ATF) is not normal and we were just using a blue dye in the ATF to test lubrication distribution in this unit.
This is one of the machined aluminum case halves. This part started life as a solid block of metal! Machining the cases is a quick process for prototyping but it is far too wasteful and expensive for production. The second picture below shows a newer cast version of same part (from the other side) after post-machining. This is how we will build the production gearbox cases.
This is a completed and assembled gearbox prototype ready to go on the dyno. The motor attaches to the top in the picture on the far right and the output shafts to the wheels are in the bottom center of the two pictures on the right. The outputs holes are plugged with aluminum covers to keep oil in and dirt out during assembly.
And finally here are two pictures of a prototype gearbox being tested on the dyno. We run many different tests to thoroughly beat up the gearbox in a more aggressive and controlled environment than possible in a vehicle. One of these tests called the “Wide Open Throttle” or WOT test repeatedly simulates vehicle accelerations from stopped to high speed at maximum torque and then back to a stop under maximum regen. This test is repeated hundreds of times back to back.
Range
I have mentioned on several occasions that we are making parts more efficient in migrating from the 1.0 to 1.5 design. The PEM, motor cable, motor connections, and gearbox are all incrementally more efficient. When all of these are added up it amounts to a meaningful increase in overall vehicle range of around 10 miles.
One common question is why doesn’t the range drop since the motor current and torque are increasing? The answer is one of the beautiful characteristics of EVs. The efficiency of this new powertrain when compared with the 1.0 powertrain is actually BETTER at ALL of the operating points that they have in common. This is the exact opposite of how two gasoline engines would compare (an 8 cylinder engine versus a 6 cylinder engine for example.) With an internal combustion engine the efficiency of the larger engine is usually worse at all cruising power levels.
When the 1.5 powertrain is operating at torque levels that are higher than what is possible with the 1.0 powertrain a direct comparison is impossible but the efficiency levels are still very high. The efficiency remains relatively flat all the way up to maximum torque and power. Keep in mind also that very little time is actually spent in the vehicle at above 280Nm of motor torque (the previous limit to the 1.0 system) and on the drives where you do spend lots of time at full throttle you generally are not trying to maximize your range!
Thermal Performance
Along with improved efficiency the 1.5 powertrain will have improved thermal performance over the 1.0 powertrain at all common operating points. This is due to the efficiency of the PEM, motor and gearbox and also due to the slightly increased gear ratio. (Increased by about 12% from 7.4:1 to 8.27:1) This gear ratio change will reduce motor current by about the same ratio ~12% for a given vehicle operating point and this will reduce the thermal load on the motor and PEM.
When operated at torque levels beyond the 1.0 ceiling there is no baseline to compare against. One thought experiment is to imagine that the car is driven hard enough to limit motor performance due to temperature. Once in this condition the 1.5 powertrain will always have about 12% more torque to the wheels than the 1.0 (due to the gear ratio) for the same energy dissipation in the motor. Before thermal limit the 1.5 powertrain will have an extra ~33% from the motor plus ~12% from the gear ratio (45% total) better torque output to the wheels than 1.0.
Peak Power
Although this improved powertrain will have ~45% better torque at the wheels it will not have a significantly higher peak power output and it will not have a higher peak battery current draw. (The two are directly related by the efficiency of the PEM, motor and transmission) Our goal has actually been to keep the peak battery current at the same level (about 650A).
It is best to think about the PEM as an electronic transmission. The car with a two speed transmission didn’t have a higher peak power output either but it could achieve a faster 0-60 mph time because the gears multiplied the motor mechanical torque. We are using the PEM to multiply the battery current by stepping up the current to the motor while we step down the voltage.
What is coming next?
Testing, testing and then more testing! Over the coming months we will be continuing to exercise and push the new powertrain components to their design limits on various bench tests. The gearbox, motor and PEM will all spend many more hours running on dynamometers at high and low speeds and temperatures. This accelerated testing will be happening in parallel with upgrading the majority of our engineering fleet of vehicles and several marketing vehicles with the new powertrain 1.5 components and then testing them as fully-assembled vehicles. One car will be taken to Death Valley this summer for aggressive hot weather thermal limit testing and hill climbing tests. Another vehicle will be running a 40,000 km durability test around a track at high and low speeds, over rough cobblestone roads, through salt spray baths and potholes. Still other vehicles are slated to undergo transmission abuse testing and vehicle firmware testing. All of these tests are designed to find any problems before they have a chance to show up in production vehicles.
When all is said and done, this evolution of our powertrain system results in a vastly improved overall product for our customers. We have maintained the key performance targets while increasing efficiency and durability. The more powerful torque curve will make the overall driving experience even better than what was reported on in the major car reviews earlier this year.
Although we faced a significant setback last fall when we realized the previous 2-speed design was not sufficiently durable, the Tesla powertrain team is accomplishing an extraordinary feat in not only overcoming this setback but engineering a superior outcome for Tesla customers.
Posted in the categories: Vehicle Engineering
Very impressive! You have taken a car that was already an engineering marvel, and significantly improved it. Bravo!
Wow! This clears up a lot of misconceptions, thanks for the extensive update. I was sure I read somewhere that this was going to be a water cooled motor. Water cooling, although effective, incorporates other losses in pumping the water and a radiator fan, so it is certainly better if you can accomplish the power increase without water. I admit that I find it hard to believe that you get 33% more power with 12% efficiency gains, and don’t draw more current from the batteries. Let me clarify, you state that the new PEM can supply significently more current, 850A, any you also say that the motor produces 30% more torque at 850A. I concluded that this higher current would only be drawn above the 60mph shift point of the old transmission, (I estimated 78mph). Now under the Peak Power section, you say the peak current draw from the battery is only 650A and that the PEM provides more current at a lower voltage. I don’t see how the PEM could possibly do this, it cannot supply more current than it consumes (unless it incorporates a transformer, which I don’t believe it does). The PEM’s increased efficiency will result in less voltage drop, providing the motor with more voltage at the same current. The battery pack will produce less voltage at extreme loads, but this doesn’t make things more efficient, or increase power. Can you clarify this apparent incongruity?
The other thing that I had mis-understood was the drive arrangement, I thought that you still had a differential (in the conventional sense of including a seperate gear). You did not mention this, but the 8.27.. gear ratio would be about right for motor to wheel rotation, so it seems unlikely there are any more gears in the system. But now I conclude that the output gear of the transmission is the differential ring gear. Am I right? Also since there is a higher new gear ratio, and the same top speed, am I right in assuming the new motor and controller is capable of higher rpm?
Totally, totally, amazing!
The Roadster just keeps on getting better and better! What’s really amazing is that you got all this performance from just fine-tuning (well, a little bit more than just fine-tuning) the drivetrain. The battery pack wasn’t even touched!
You guys covered everything, and more, but there is something that was left out.
Months ago, articles were talking about Tesla needing to improve the cooling capability of the motor. None of that was mentioned? Did Tesla improve the cooling, or did you keep the design? Why or why not?
I’m assuming an improvement in motor cooling wasn’t required since “gear ratio change will reduce motor current by about the same ratio ~12%” Am I correct?
You should do some dirt testing as well, have you considered entering any rallycross events?
www.johnsonvalleyrallyx.com/
www.myautoevents.com/pls/mae/frmEventDetail.Show?psevent_id=8370
You have till nov 1 to get ready for the dirt…
go on, really you should!!
Thanks for the update, J.B.
## “we have also done away with the need for an electric oil pump and instead integrated a very efficient gear-driven oil pump into the gearbox.”
Ah… mechanically driven pump… Nice. I was wondering what would happen if you towed the roadster and failed to activate an electric pump. This solves that concern.
How does the sound level compare? All the EVs I’ve known have exhibited some gear whine. The 1.0 drivetrain wasn’t bad. Is the 1.5 drivetrain any quieter given fewer parts at work?
Roy: I suspect that the Powertrain 1.5 is using some sort of “buck boost” circuit to drop the voltage and increase current. The advantage of a buck boost circuit is that it can be electronically adjusted to various voltages and currents, unlike a fixed ratio transformer. The reduced voltage / high current output is used for high torque at low speeds, at higher speeds it “shifts” to a higher voltage / lower current output to overcome the increase in back EMF force. Toyota engineers used a similar circuit in the 2004 Prius to boost the voltage to the motor at high speeds.
Tesla could have used a different approach, by using a large number of relays in the battery pack to effectively “rewire” the battery into a “more parallel less serial” arrangement to increase the current and reduce the voltage. That design would have been a bit more efficient, but it would also have added cost and complexity, and increased the potential risk of failure.
As for the gear ratio of the differential, I suspect Tesla Motors is using a transaxle that combines transmission and differential into a single compact unit. If that is the case, the gear ratio mentioned already includes the ratio for the differential.
yes - the gearbox incorporates a differential - ed.
Totally, amazing!
And you ll upgrade all of it for free 
Thanks for the update 
Dear TM Team,
Thanks for this update and the superb pictures. The Tesla Roadster keeps getting better and better! What is definitely a hurdle for newcomers like TM and other EV manufacturers in the market is the fact that their vehicles are not in every aspect perfect. Don’t get me wrong! The Tesla Roadster is probably one of the few exemptions but as the report shows, there is also more finetuning required. This fact can hold back potential buyers…People nowadays expect the perfect car but hey, if you buy one you not only help the EV revolution, you also help to keep the development going! And in a few years from now you will be called a pioneer!
JB Thankyou for taking time out to post this important news. Congratulations to you and your team.
Given the benefits of reduced cost/complexity/weight and slight efficiency gains of this new drivetrain, do you see this as the end of multi-gear gearboxes in EV applications? Will whitestar etc be single speed as well?
The reason for asking is that gears 1 and 2 did allow for switching between different regen profiles. Is the Roadster’s regen now a single factory-set profile or is it tunable? Could this idea resurface in whitestar as part of a “Normal/Economy” selection system?
**and on the drives where you do spend lots of time at full throttle you generally are not trying to maximize your range!**
Have to love that quote
A great update!!! I hope the final tests on the Powertrain are a success.
jb
What IS happening with the regen profiles?
Gearbox 1.0 and Motor were said to have 17 moving parts. What is the new count in 1.5?
Do you have (projected) times for 0 to 30, 0 to 60, and 0 to 100mph?
I’ll try and answer a few questions at once here:
Malcolm, regarding 1 vs. 2 speeds I think there will be a continually stronger benefit over time to use a single speed design for EVs. There are already many good reasons to stick with 1 speed but they will become even more obvious and dramatic as motors and electronics continue to improve. Our sedan project will use a single speed gearbox. In fact it is going to be VERY similar to this new gearbox re-using most of the internal components and designs. That is how we can accelerate the sedan project by leveraging this work. Regarding regen it is true that with 1 speed you won’t be able to adjust this. We are definitely working on new ways to allow the driver to “tune” regen feel but it is a tricky issue due to braking systems homologation.
Roy and CM, the PEM is operating as a buck converter from a voltage standpoint. As it takes DC voltage from the battery and converts this into 3-phase AC voltage to the motor the peak of that AC voltage can never be higher than the battery voltage. However the AC current output can be stepped up when the PEM is bucking to a lower voltage. So related to the torque-speed curve we have increased the motor current and torque (by about 30%) below the peak power point. At the peak power point there is little change, only that caused by efficiency improvements. Above the peak power point we see some improved torque but it is less than 30% because in that region motor torque is not linear with current increase and we are essentially “voltage limited” by the battery pack.
Joseph, you are correct, a change in motor cooling was not required and the motor is still air-cooled just as in the 1.0 powertrain.
Steve, so far it looks like this gearbox will be slightly quieter than the previous gearbox that you probably experienced but there is still that familiar and friendly “turbine whine” that comes partially from the motor itself.
Thank You for the update, and informative post.
An efficiency update of this magnitude would have taken the other automakers decades to pull off! I’m ready for my Whitestar right now today!
I like that the 1/4 mile is below 13 seconds - Isaw a show the other day, where hard-core tuners (best 10 in the states) were racing. Top 3 were below 12 sec. the rest below 13. This is one fast car, and I bet a lot cheaper to maintain…
JB,
The update was great and all good news. But what I really wanted to thank you for was actually coming back and posting answers to as many questions as you could. It is greatly appreciated that you took the time to do so
So the motor speed increased slightly, but the gear ratio rose significantly. Does this mean the top speed is ~10% lower or is it still limited to the same 125 mph like in powertrain 1.0?
Sounds like things are going well. Is Elon eating some humble pie for his insistence on a two speed transmission?
Wow, fandamtastic. This is the best blog yet. What you are doing is truly amazing. This car is SICK. Keep up the great work!
Joseph: As JB noted in the Thermal Performance section (and I think you realized in your second post), “Along with improved efficiency the 1.5 powertrain will have improved thermal performance over the 1.0 powertrain at all common operating points. This is due to the efficiency of the PEM, motor and gearbox and also due to the slightly increased gear ratio. (Increased by about 12% from 7.4:1 to 8.27:1) This gear ratio change will reduce motor current by about the same ratio ~12% for a given vehicle operating point and this will reduce the thermal load on the motor and PEM.” The efficiency improvements have made the need for a water cooled motor a moot point.
Also, the following statement makes me very hopeful for a sooner turn around on the Whitestar:
Our sedan project will use a single speed gearbox. In fact it is going to be VERY similar to this new gearbox re-using most of the internal components and designs. That is how we can accelerate the sedan project by leveraging this work.
I am absolutely blown away - just floored. You salvaged a serious situation with solutions that had little or no excessive impact to the subsytem - quite the contrary, it sounds like all things ended up better. You must know that you are now the leading experts IN THE WORLD for EV drivetrains. That makes you the absolute BEST in your field. Well done!
This sounds great, it really does. But for the love of god, will you guys PLEASE make an electric car for the rest of us? We’re dying out here! The company that finally puts a
Thanks for explicitly confirming that the motor is no longer water cooled. I could tell by the pics and explanation that water cooling wasn’t necessary, but it’s always good to explicitly state the obvious. I was concerned that water cooling would just add more complexity and another maintenance item, but it makes sense that the higher rpm motor and higher gear ratio would eliminate the need.
As for Elon eating humble pie, his only desire was for the car to have supercar low end acceleration, as well as a high top speed (not just 90 - 100 mph). If the motor stayed at 10,000 rpm, one, the other, or both would be sacrificed. The creative solutions from the motor and drive train experts at Tesla Motors produced a solution that maintained the low and high end performance characteristics to keep the Roadster in the supercar class, while improving efficiency and avoiding the need for water cooling. That is absolutely amazing, and gives everyone what they wanted.
Is it true that future Tesla Motors motors will be able to operate up to 20,000 rmp?
Thanks for the update. Sounds like you’re making fantastic progress. I note that you don’t mention 0-60 times, but it seems like they must be improved. Am I right in guessing that you’ve been asked not to release them yet because management and/or marketing want to announce them at a strategic/dramatic moment?
Good job. Now get back to work on Whitestar! We really, really need an alternative to gas for the rest of us.
Keith
Being a newcomer to electric cars, I find your updates great! Like Snead, though, I am for an electric car for the “rest of us”! We need it, and whoever comes up with it is going to make a fortune! I am betting on Tesla, but the competition is formidable. That, though, is why competition is good!
Great work! Did anything have to be done to the frame/chassis/motor mounts to handle the 45% increased torque to the wheels?
Wow. That’s what we like to hear: better in every way. Great blog too; the tech blogs here usually show off some amazing things, and this one is a prime example. I sure am looking forward to being floored by a Whitestar blog here shortly….
On another note, how’s that Magna suit going? I’ll bet they’ll find it tricky arguing that you should be buying a system from them that’s inferior in all ways…
Love the details in this blog. Great stuff! Any chance to see an update of the power and torque charts?
My understanding was the 0-60 was the same due to the gear ratio change to accomodate a similar top speed without a second gear. The number that should be improving is in the 0-100 saving the gear shift but I am not sure there was anything published officially for the 1.0 transmission for 0-100 anyhow. In any case, I second the request for official 1.5 specs for 0-60 and 0-100. Thanks!
JB: Thanks for the response, I never considered that the PEM would contain a buck converter. That explains everything. The buck converter becomes the electrical equivalent of a lower gear. I agree with Jason’s statement that you guys must be THE premier experts in the world on EVs. Jason a 12% gear change would suggest an increase from 13000 rpm to 14500 rpm.
I was trying to find out how well this car will perform in a cold climate. I noticed there will be a dealership and service center in Chicago. Does this mean that the car recovers heat from the motor to heat the cabin or is there an electric heater that draws from the battery pack. I could not find much information on this.
Tim electric heater and I think they will have a heated seat option too once they expand outside of CA. The nice thing about electric heat is that it is instant one no need for the ICE to warm up like in a typical car.
Nice presentation; When I see the advances you have made in the drive and control gear, my mind takes me to the racetrack and speculation on how the car could be modified to run a twenty minute sprint race. How about taking one of the prototypes, remove all the unnecessary weight, add a race seat, slam the car as low as it will go, crank in negative camber, install the 1.5 drive line and controller, add some race wheels and tires and modify and lighten the battery to carry only the power you need for thirty minutes on the track…would be one killer track car!
“One of the most exciting features of this new gearbox (from an EV perspective)…. is that it has extremely low spinning drag (less than 0.1 Nm of dry drag torque.) This is less than any other gearbox we have tested with the only possible exception being the EV1 gearbox.”
The EV1 really was an engineering marvel. I wonder if Tesla has tested (or gotten info on) the FCX Clarity transmission. Honda is a pretty clever car company. Has Tesla tested the Rav4 EV’s transmission?
Wired seems to think that the Roadster now has a 4.0 second 0-60 time. Is that accurate?
blog.wired.com/cars/2008/05/tesla-v15-has-r.html
Well done. Superlatives cannot do the effort justice. One thing I’ll add to the discussion about you being the best in your field . . . your timely work also saved the car, the company, and the future production stream (assuming it all works as advertised).
As I recall, last fall the previous transmission effort was the subject of some ridicule from those who saw it as odd that, of all parts to fail muster, it was a part that had been around for years–the transmission! Of course we now know that this criticism was, at least in part, unwarranted because it was an artifact that served to highlight the fundamental difference in performance between the electric engine and the ICE. (In fairness, the criticism was in part warranted because it was a fairly obvious difference to the initiated.) And now that artifact is eliminated! There is simply no better response to criticism than to eliminate its source (and no, I don’t mean the “Stalin Method”).
Are we going to have to find an equivalent of Moore’s Law (en.wikipedia.org/wiki/Moore%27s_law) to describe improvements in electric cars? If so, who would we name it after?
Excellent write up.
www.ecogeek.org/content/view/1678/69/
OH-OH!!!! Serious Competition here!!!!! Time to step it up boys!
JB. Thankyou for the answers.
“We are definitely working on new ways to allow the driver to “tune” regen feel but it is a tricky issue due to braking systems homologation.”
Yes regen still has to work with traction control and vary with motor revs, car attitude etc. Safety is paramount. The other problem is that if you give drivers the option, they will tend to tune regen to give a familiar ICE engine braking feel which may be at odds with optimising for electric motor/generator energy efficiency. Tesla’s products have to tread that narrow line between satisfying expectations based on years of conventional motoring whilst drawing customers toward habits which get the most from the new EV technology.
In relation to habits, I know that Tesla Service Engineers can download “black-box” information from the Roadster when it comes in for servicing. Is Tesla able to give us a blog entry outlining the broad information categories and how this will feed into both Roadster 2.0 and the Whitestar project?
One for your growing team of lawyers: Do Roadster / future owners need to sign an agreement to allow Tesla to use this downloaded information?
Have you considered making the car 4 wheel drive, alternating the drive from front to rear wheel drive.
The end of the car not in drive mode could switch its wheels to drive alternators to trickle charge the batteiries as the car is moving?
Darin Ladd,
More than saving Tesla Motors, these trail blazers are saving the US and World by showing the way.
As for multi-speed transmissions, when single speed BEV’s and REEV’s become commonplace, I predict that one or more EV shops are going to introduce EV’s that can travel much faster than 125 mph. They might achieve this through increasing motor speed to 20,000 rpm, or they will achieve it by putting a reduction gear between the motor and the multi-speed transmission, and using a standard high performance transmission which on sees 5,000 - 6,000 rpm max. It was the combination of high torque and high speed that killed these other transmissions, so this simpler arrangement, while less efficient, will be very high performance.
Steven,
Nice idea but that falls into the perpetual motion category. In reality, the alternators require more energy than they produce. Not possible with the current physics but perhaps if the universe changes it will work LOL.
Updates like this one was exactly what was needed to revive the image of the Tesla roadster. The combination of transmission problem along with delays in delivery really made me (and many others) doubt such a marvel of engineering. Please keep updating the general public so that speculation does not tarnish the real progress being made. Mr. JB Strabel quoted an improvement in the quarter mile (12.9 seconds) but did not provide the old quarter mile time for the 1.0 drivetrain. Also, Mr. Strabel left out the new 0 to 60 mph time (I have read the 0 to 60 mph time for the 1.0 drivetrain was 3.9 sec; please correct me if I’m wrong on this figure).
Regarding the Hybrid Technologies car, i think the relevant quote from the article is, “when they finish building the first prototype later this year.” They haven’t even built their first prototype, so anything they say about performance, range, etc. is just guesswork. And if their first prototype won’t be done until late 2008, there’s no way they’ll be in production in 2009 or early 2010. They’ve got to get that first prototype built, learn from it, make more prototypes, learn from them, make more for crash testing, do the crash testing, and only then can they start production. By the time they get their car on the road, Tesla ought to have the Whitestar out.
Keith
Tim, see this blog www.teslamotors.com/blog4/?p=43 titled “Blowing Hot and Cold” for a very detailed description of the Roadster’s HVAC capabilities.
Steven, I’ve got an idea! Why don’t you make a wind-up-toy car and attach the crank to the drive wheel so it winds itself! It’ll never stop!
Jason, when did you get religion on the single-speed?
Thanks for such a fantastic informative post! Your detail and openness is greatly appreciated.
Hunter,
“I got religion”, when Tesla Motors developed a drivetrain that could demonstrate that a single speed transmission could maintain both the low end acceleration and high top speed characteristics of a multi-gear transmission vehicle; thus allowing the Tesla Roadster to still call itself a supercar. Had they ended up with a sub 4 sec 0 - 60 acceleration with only a 100 mph top speed, or a 6 sec 0 - 60 acceleration with a 125 mph top speed, the Tesla Roadster would have been a joke. It is absolutely critical that the American car buyer see that EV’s maintain comfort and performance, while greatly increasing energy efficiency, eliminating emissions and cutting our use of foreign energy sources.
The tesla roadster have a supercar acceleratin but not a supercar top speed. Thats way the tesla roadster is only a sport car.
In US and europe the speed limit is ony 55 to 90 mph. So 120 mph for the roadster is good starting point.
If i can drove 55 to 90 mph highwayspeed a range of 250 miles everything is O.K
If the batterypack ESS a the inverter can handel a higher Voltage like 900 Volt would the rpm be higher?
The fastet electric train in germany ICE have a top speed of 255 mph without any gear changes.
Bring this car to germany we have 8.77 doller per gallon.
Hello Guys of the Tesla Car.
It is wonderful to see your work, I would gladly buy one of your cars someday.
But I’m writing to tell you a little story. Four years ago I left Brazil to a six thousand kilometers (4000 miles) trip to Bariloche, Argentina, with a motorbike. Returning home I choose the badly kept Ruta 40 over the Andes, and visited several high and low places along the path. In one of the passages I crossed, nearing three thousand meters high (10000 feet high over sea level in your measures), the bike engine mercilessly failed, and second gear was almost of no use. (Have I also to tell you that I had to ask for fuel as it finished along the route?
Your car wouldn’t suffer the effects of high altitudes, it would be a perfect companion for such a trip like the one I did. It wouldn’t do half mileage like my bike did, nor it would fail to perform its trip due to lack of air. For people that live over the Andes or the Himalaia, your car would just be the best choice.
And if you want an adventurer/driver to test your car in the roads of South America, I’m ready for the taking
Good job!
Tiago
All the improvements are great news. I hope to purchase a Telsa and charge it from solar panels at my home on Orcas Island, WA. Keep up the great engineering work!
Interesting gearbox.. the gears have a surprisingly large face width and fine pitch. They’re also asymmetrically supported. I would have thought this would create an expensive gearset + gearbox to achieve the high tolerances necessary to maximise the benefits of such a geometry! What type of coupling are you using - interesting riddle “what spins at 14,000 rpm but transmits 400Nm?’ not much to choose from I bet. Have you considered whether the coupling might become unbalanced after the splines wear a little bit?
Cheers,
Ben.
Wow, this sounds pretty cool for future developments. Regarding testing I miss a point thou: Yes, a Roadster is mainly driven in summer. Nevertheless, sometimes it happens that one wishes to drive during wintertime. Now regarding your European special offer, has it been tested how the car behaves at let’s say 0°F (-18°C) and how passenger AC would drain power in such a case? Just curious…
Cheers
The Swiss
The Swiss: see www.teslamotors.com/blog4/?p=43 and www.teslamotors.com/blog4/?p=43
I assume at 0 you would be using the heater rather than AC but in any case is not should signficantly affect range and the battery is kept in a suitable temp. (prevented from getting to hot or cold) to ensure its performance.
JB, Since you already have a buck converter in the controller, can it be configured as a boost converter during regen at low rpm?
Darin:
The unit of measure of EV improvement is called the *Eberhard*. :-/
Excellent article and pictures…. No hype just factual information. I’m also glad to see the simpler and more energy efficient transaxle.
Keep the articles coming. One aside: Can anyone tell me how many Tesla’s currently have been produced and If any have been delivered to non-Tesla people? Thanks, Bill.
Please tell me that it has remote power sideview mirrors. I was scanning through the list of features and pics of the interior and couldn’t see any evidence of it.
Just what the doctor ordered! Couple this rig to a battery of solar electric panels designed by Prof Vivian Alberts of Johannesburg University which right now is being produced in Germany , China and soon in South Africa under licence at 20% of the cost of the old silicon based panels and we can all learn how to say goodbye in Arabic . Google Alberts and get up to date on the this most amazing development - that few people seem to know about - that will change our lives as far as our electrical needs are concerned.
oh and once again from someone who drives and loves slippy roads…
Consider producing a 2 motor car - 4 wheel drive - it will do wonders for your handling, and reduce your amp loads per PEM as well as improving performance/handling under max regen braking.
again, consider some rally events for truly testing conditions. It would also give you Huge exposure if you could win a event, it would be huge worldwide news among engineers and enthusiasts!!
or if you are halibuts you could always be the 0 car for some rally, then you wouldn’t have to compete.
www.californiarallyseries.com/home/index.aspx
come on, man up and enter if you can get the range. or design a quick change battery pack, service should be long enough.
JPB;
Solar works where and when there’s enough sun and real estate. NYC will not charge its cars on solar. Ever.
Thanks for the very clear and informative post, J.B., and congratulations on the apparent success for everyone’s hard work on this project.
Is there any complementary news on improvements in the ESS? Newer, higher-capacity, longer-lived batteries, perhaps? Or a breakthrough on the ultracapacitor front?
Greetings!
I am apreciador of your car and an admirer of Nicola Tesla.
I think he was like, if you bring your car in a Perendev magnetic engine. with this engine connected to a dynamo, can charge batteries without external sources. Search on Google about Perendev magnetic engine.
Tell me what you think about this.
Simon Jester,
Wow, Eberhard has been gone for several months, and you are still trying to credit him with other people’s work.
To me, an Eberhard is a unit of time, which conveys the amount of time delivery slips while you ignore subsystems outside your area of expertise, in favor of polishing subsystems with which you are more comfortable. Considering that he single threaded the transmission development with no competition, nor alternatives as a backup, the Tesla Roadster was delayed by at least two Eberhards.
Great news – great blog. Watching Tesla grow has become my favorite spectator sport!
Question: Is The Tesla Motorworks division dead? I know you guys are working night and day and the Roadstaer ands we assume that the same is going on the WhiteStar (The car I’m willing so sacrifice for btw), but there are so many other opportunities for high-quality durable electric motors – most notability, lawn mowers.
I think it’s accepted that the air pollution from cutting grass for an hour with a gasoline-powered lawn mower is about the same as that from a 100-mile automobile ride. That’s going to vary but I think it’s safe for the discussion. Every time I mow my lawn I, create nearly as much pollution as my entire weekly commute to work. Each year, mowing my yard creates as much pollution as driving my car approximately 3000 miles.
Briggs and Stratton make engines for many different manufactures. How great would it be if, in a few years, all those mowers at the Home Depot had a little Tesla badge on them? One simple motor design is all that would be needed for every push mower in the world. The only option would which battery pack you needed. “I’d like the two hour battery please…”
I think I’m correct in assuming that the Tesla motor would last 15-20 years at 30 hours of use a year. I’d pay triple or more for that. What about you guys?
I echo the question above from Tim concerning cold weather. I live in a cold climate and have a 180 mile round-trip commute (I could plug in at my place of employment I think so the 180 miles shouldn’t be an issue).
I don’t think tesla motors should get into the lawn cutting business but you have green alternatives now plus having a robot do it saves you the time. The following site lists a number of reviews and options:
www.bamabots.com/
Very good update. While my engineering knowledge is minimal, I am always glad to hear of progress like this. We at OE will be keeping a close eye on progress. And…I’m hoping we’ll get a chance to visit the store in LA sometime soon.
-Garret
Does this transmission have a pair of constant velocity joints similar to a FWD car? I guess my question is how are you delivering to power to the actual wheels?
Is the Tesla Roadster FWD or RWD?
Is it posi, or just one wheel drive?
Is the motor in the front or in the back?
Vinagrini: Perendev looks like a scam to me. No specifications. Auto motor/generator is two units connected together!? Why, makes no sense. All motors are drawings, no pictures. Says house can be powered by auto generator but makes no mention of source of power.
William: See www.teslamotors.com/efficiency/how_it_works.php rear motor differential with traction control.
Better performance in everything and still 10 more miles. Kudos to all the technicians!
William, if you can’t be bothered to read the information freely available on this site why should anybody be bothered to answer your questions? On the other hand if you would like to place a deposit to purchase a car I’m sure the Tesla team will come up with some answers for you!
Ian et al.;
I don’t have the link handy, but IIRC there was considerable cold weather testing in Sweden or somewhere early on, and there was no problem. On the “tech specs” page it lists: “Cold weather ESS heater for cold weather charging to -20 degrees Celsius” as included with the car.
Pete:
The idea of the Motorworks was to collaborate and “spread the word” to other uses. It did not imply doing the manufacturing at Tesla.
@scottO:
Let’s take that a step further; how about a well designed BELT (Battery Electric Lawn Tractor). Some time ago GE built one; but, the weak point was the battery. With today’s more efficient controllers and batteries, etc., I think it would be an fun engineering project to size the components to fit the specs.
Andrew, I’ve spent *hours* reading posts on this site, and still didn’t find the information that I was looking for. That’s why I posted the question. I *did* place my $60K deposit already (for a 2009 model). I was hoping some kind people on this forum would help me out. I’m sorry if I somehow offended you.
I have to say, this is car is pretty much everything I’ve been looking for. it almost brings a tear to my eye because of the shear awesomeness of it. I do have one question though. I’ve heard about new Transparent Solar Cells that can be integrated into windows to provide electrical energy for homes and possibly cars. Has Tesla Motors ever considered using this technology on this car? With regenerative braking adding more power to the battery to give the car a higher estimated city mileage than highway mileage, why not try something like solar cells to help even out the city and highway mileage? Every little bit helps, right?
William,
Here is a page you may have missed, www.teslamotors.com/design/under_the_skin.php Plus, the blog “The Spin Stops Here” at www.teslamotors.com/blog4/?p=65 has plenty of details and videos that will answer your questions.
I am surprised to learn that Tesla does not give their customers contact information where they can get answers about their car.
This is fantastic/amazing news!
Bravo to Tesla motors for not only making a fantastic car, but a fantastic car even better!
I can’t believe what you guys have managed to pull off. Incredible.
If Tesla Motors considers trying to enter a market other than passenger vehicle production, I would hope that they would consider an EV version of a short-haul cargo vehicle.
Short-haul/local truckers have many characteristics that would lend themselves to EV applications, and of course have additional benefits from energy savings/pollution cutting issues as well. It also has an additional advantage of being a high value / low production volume situation that seems to fit Tesla’s current business model. Certainly there are businesses that wouldn’t object to spending $300k each on an incredibly reliable and fuel efficient short-haul truck that could be recharged on-premises as well.
It also seems as though efficiencies would also improve and scale with the size of the motor, but perhaps I’m mistaken on this issue.
Yes, I’m aware of Zap and a few other EV manufacturers that have trucks, but those are all punishment vehicles that would also in the long-run punish the companies that buy them as well. You need vehicles that can get to highway speeds and have at least some reasonable driving ranges to break into the short-haul business, unless all you are trying to drive is a glorified fork-lift truck. This isn’t a pickup truck I’m talking about either, but an EV replacement of a semi tractor.
The kind of vehicle I’m describing can be seen in this video:
youtube.com/watch?v=0f1AlrG8gVU&
I’m not trying to promote anything, as I have absolutely no relationship to the above link or the group making this particular EV. This is strictly to illustrate that it isn’t necessarily a unique idea and that some progress is being made along this line of thought. In this case the Port of Los Angeles is helping to underwrite the costs of this vehicle, which makes me scratch my head thinking about what engineers from Tesla could do to compete against the company making these vehicles.
Mark, thanks for the link to the blog about the Traction Control system. It was a fascinating read. That seems to be the only page on this whole website that says that the roadster is RWD. I’ll assume that the engine is in the rear and that it has posi, but I haven’t actually seen it “in print”. As far as the posi goes, does it have a normal differential like an ICE car? How do they allow slip so that one rear tire can go faster than the other (when going around a turn)?
Also, does anyone know which subsystems of the car are run off of 12V DC? I’m sure that the JVC radio/nav unit is, but what else? Is there a 12VDC normal car battery in there somewhere? How does it get charged? How crazy can I go with an aftermarket stereo system (custom head unit, backup camera, lots of amplifiers etc)? Some of my cars have been featured in car stereo magazines and I’m very much into this sort of thing.
I’d like to throw away the tachometer. With a single speed tranny and no clutch or torque converter, the tach becomes the same thing as the speedo and is not needed.
Is the speedo just an off-the-shelf mechanical unit with a rotating cable as the input? Is the speedo just an off-the-shelf digital unit with the normal “so many pulses per mile” input signal? I’d like to throw away the stock speedo and replace it with a cool custom digital dash or headup display.
The tech specs page still has the 2-speed transmission data. Needs updating.
Eric Y: First there is no such thing as transparent solar cells. There is a recent news article on a transparent protective coating for solar cells. Many people have suggested solar cells on the roof and hood. This is a possibility but the area is not enough to be sigificant, best case might be parking in the sun for 6 to 8 hours would give about 4 miles of charge. Tesla recommends putting solar cells on the roof of your garage and/or house, as this is much more cost-effective.
William,
Right under the Performance tab (see Performance Specs subheading, Style section) at the top of this page you can find the reference to the Roadster being rear wheel drive.
Pete, you’re right. I must have missed it before, but it’s right where you pointed out. Thanks. Now I’ve still got to find out if both rear wheels are driven, or just one. I’m sure everyone here is under the assumption that both wheels are driven, but is it documented anywhere? I’m sure that they wouldn’t have had all those troubles fine-tuning the traction control software if the roadster was one-wheel-drive, but I’d still like to know for sure.
Robert Horning,
Smith Electric Vehicles, with design support from Ford, has a full line of electric trucks:
www.smithelectricvehicles.com/index.asp
Matt Damon seen driving a Tesla prototype - I wonder if he has the new 1.5 transmission in it. I would have to guess it does, if they allow him to take it without any Tesla sales or engineering people with him.
www.autofiends.com/index.php/2008/06/matt-damon-caught-test-driving-tesla-prototype-wants-one/
Roy: All modern EV controllers, (Tesla calls it the PEM) even those used on simple machines, such as golf carts and forklifts are working like transformers. As another reader pointed out they are buck converters (not boost). They enable more motor amps than battery amps, but at a reduction in voltage.
For example (with no loss figures included for simplicity), assume you have a 100 volt battery pack. When you begin to accelerate, the controller can put out say 10 volts, and drain 100 amps, this is only going to be 10 battery amps! Amps X volts = watts. The controller can drop the voltage and increase the amperage, and this is almost infinitely variable. This effectively makes the PEM on the Roadster like a CVT (Continuously Variable Transmission).
JB: Keep up the good work, I’m rooting for Tesla!
-Phil
Jason Hendler,
No, that one does not have the 1.5 drive train. There are only a couple of those and they are all being used for testing and evaluation right now. I don’t hink there is one in LA at all. I just drove the Roadtser on Friday and you can too…with a small deposit
William,
Did you really put down a 60k deposit on this car without the answers to these questions? I have been given all kinds of information by the Tesla Team and they are not shy about sharing thier time with “owners.” If you really have these kinds of questions to ask (as a customer with a 60k deposit) you should pick up the phone and call the company.
Mark Tomlinson- Yes, Tesla does give their customers great contact options for information about their car. I’m surprised that one of their customers would feel this blog is his best source for information.
Tim M,
Thanks, the first link that I had for the Matt Damon story didn’t clarify the transmission configuration, but then I posted the source link for the story I read without reading the source link first. I could have saved us both a post had I spent another few seconds looking at the source link.
Power Cable?
In the “D-1″ picture above—is that the grey power cable hanging or a communication/control cable (or both)?
If a power cable—how many amps do you end up drawing at max on average and I also wondered what is the inrush current is from a dead stop?
Just curious
Nathan
Tim, yes I did really put down a 60K deposit without knowing all the answers. They said that I’m looking at about 15 months before I get my car, so I figure there’s plenty of time to back out of the deal if I find out something about the car that I don’t like. I figured that if I ask all this stuff here (instead of calling), then maybe others can benefit from the info as well. Is there a certain person that I should ask for when I call?
William, welcome to the club! You’ll want to setup your password into the owners section. There you can select options for your car, contact your sales consultants, and converse with other owners. I forget exactly how to register, it’s been a long time.
William, I’m sorry if my previous post was a bit rude. I’ve been following Tesla’s development ever since these blogs began and I was a bit surprised that you hadn’t found the information you required. It just looked like laziness to me and that’s why I wrote what I did. Anyway, as others have pointed out, if you have placed a deposit, I’m sure Tesla would be very happy to spend hours explaining every detail of the car. I hope you really enjoy your Roadster and I’m sorry for any offence given.
Daryl tells Fast Lane Daily that powertrain 1.5 gets the same 3.9 second 0-60 and top speed of “very close to 125″ which I’ll assume means over 120, but not able to go over 125, so no longer electronically limited…
www.youtube.com/watch?v=AP1PYST6iac
Thomas, thanks for the heads up on the owners section, I’ll talk to my sales guy about it.
Andrew, no offense taken. We’re all friends here. I hope to meet you all at the next owner’s drive event!
I have a question about the ‘cost’ of driving an electric car. I can fully appreciate that the cost of servicing the car will be much less as there are far fewer parts to consider and fluids to replace, but the cost per mile/km is bothering me for the following reason: Tax on petrol in the UK is (from what I have found on the web) running at about 72% of the fuel price. I did a rough calculation that using low rate electricity, that the cost for my driving would be about 10% of driving my petrol car. Now the tax man takes 72% of the petrol cost, I use 10% so the delta is only 18%. The point being is that the tax man will take his tax in one form or another (he will only get a minor amount from the tax on the electricity). It may be cheep to fuel, but when we are all driving these things, he (the tax man) is just going to get his income through some other form – road pricing for example. So the question is, should the tax angle be put into play when describing what the benefit to the consumer will be?
John Maton that’s a question that could be debated ad infinitum. For my .02 farthings worth, I think that EV use by removing pollutants, can the lower costs health care and even physical property maintenance, at the same time raising general productivity due to the increased economic efficiency of using electricity instead of imported oil. That is in addition to the fact that everyone who remains on the grid will pay their share of taxes in their utility bills so that eventually the tax man will get his share and much more.
John
You’re right. No form of energy consumption will escape the beady eye of the taxman once it tips over into mass consumption. At present the nighttime price rate for electricity in the UK is roughly 5p per kWh. www.britishgas.co.uk/pdf/Standard%20Electricity%20prices.pdf I can easily see this doubling as power providers catch on that there is a new and growing market of EV owners out there. (Mind you, that would still allow you to fill up the Tesla Roadster (slowly) for only £5:30 for roughly 200 miles of driving). But the Revenue will follow suit. Prices are bound to rise. New taxes will be introduced.
One loophole may be domestic-scale renewables, but the required levels of capital investment are - at present - high for single dwellings. We need more companies like nanosolar, trying to reduce the cost / kWh of renewables and/or more neighbourhood schemes where the output from a single, expensive renewable device is shared between a number of dwellings. Likewise, the maintenance costs are shared. Much like a communal garden.
So start saving for your share of that wind turbine as well as that EV
www.quietrevolution.co.uk/
Malcolm, I’m not so sure they’ll find it so easy in the UK to increase the price of Economy 7 cheaprate electricity. A lot of poor pensioners rely on topping up their electric storage heaters with this cheap overnight power. My mother for one! Of course they’ll charge us somehow but I’d expect to see a lot more use of road pricing with numberplate recognition cameras helping to make the whole process automatic. They can justify this on the grounds of reducing congestion and helping to control emissions. I think we should resist this with every fibre but I doubt we’ll win in the end. I think there may just possibly be a golden window of opportunity as Volt style REEVs catch on and there’s a lag before they figure out how to replace the lost petrol revenue. Hope so anyway.
Have you thought about making the back deck of the car a set of photo electric cells that could charge the battery while driving. This may increase the distance between fill ups, I mean charges.
J.B.
I do not see anywhere in the performance or specifications if the Tesla Roadster is all wheel drive or two-wheel front or two-wheel rear drive.
Did I miss it or has that not been explained?
Thank you!
Scott: thats been asked and answered many times, as recently as June 2 right in this blog.
Scott Williams - While every little bit certainly helps, the rear deck and other surfaces have been described (by others much more knowledgeable than I!) as being too small a surface area to really make a difference in that vain (based on current technologies).
Scott – In the design tab on the top of the page you’ll find some information about the drive train. It’s been a while since I’ve been there but if it doesn’t mention it, the Roadster is two wheel, rear drive. And it is sooooo much fun to drive!!
Something is a bit wrong with the gearbox. Using ball bearings allows some side play in the shafts. If you were to use tapered roller bearings, you would have less “whip” when changing gears. Just an opinion.
Hi!
And thanks a lot for finally removing that second gear!!! The gearbox now looks quite good to me. The critical part is the small gear wheel on the gear’s middle axis which to me looks quite the same as the first small gear wheel on the axis directly connected to the motor.
From view alone I do not yet trust the direct motor connection. To me it looks too fragile for 185kW of power or the backstroke of an unwanted rear wheels standstill. Is this taken care of somehow?
Best regards
JG
Here in the Northeast, we’re hoping you’ll do COLD weather (snow & ice) testing soon…..
i am doing a project for a vehicle dynamics class on traction control using the tesla roadster as a model. based on the torque curve on the website, and using a 2D rear wheel drive model (with suspension and pitch dynamics) our simulation predicted max torque wheel slip occurs with a gear ratio of 7.855. it’s cool to see that i got it pretty close to the real thing (i’m assuming you want your customers to be able to do a small burn out if they want, so that’s probably why it’s a little higher)! thanks for the info!
Can’t wait to get mine!!!!
Scott:
Click Design/Under the Skin/Motor
C.E.C. Jr.
No changing gears. No whip . No problem.
______
Some time previous on earlier posts, it was more or less the consensus that while the Stanford nanowire anode was nice, with its 10x energy density, unfortunately no compatible cathode exists. However, this may be a matter of competing sources. Have a look at this nanowire cathode: www.enableipc.com/microbattery.html . I queried them, “After reading your pdf document about your nano-cathodes, I was wondering whether these are compatible with and complementary to the anode silicon nanowire development by Chiu at Stanford. “; and they replied: “I think they would be compatible. The ideas are similar — increase surface area leading to improved performance — although manufacturing methods differ. ”
So it seems to me the pieces are available, if not exactly “in place”, for super-LiIon 600kwh batteries.
2000 mi range, here we come!
Andrew and Malcolm;
I’m pinning much hope on the success of focusfusion.org / lawrencevilleplasmaphysics.com getting their mini-DPF 5MW generators built within 6-8 yrs. They would have a 6¢/W construction cost, and 0.2¢ (0.1p) kwh output cost. Small - one per neighbourhood, right next to the greengrocers.
That would put a blinding new light on things, wouldn’t it?
Malcolm;
Quiet revolution wind turbines at $8.200/KW, $8.20/W? With a backup oil/gas generator for when de wind don’t blow? You must be joking.
Nat;
Sorry, Sweden beat you to it. www.teslamotors.com/blog4/?p=55
Scott;
More on drive train: www.teslamotors.com/blog4/?p=65 See ¶3 for details on controlling rear wheel spin etc.
There is a search box on the left margin, 4th section down, which works pretty well with multiple keywords. I used “motor drive rear tire” to narrow that one down. It seems to search the blog postings only, but that’s not too bad.
JB;
Have you considered lubricating with glycerin (glycerol)? It is used in various such applications, and has several advantages. One characteristic which might be considered a pro or con is that it is highly hygroscopic, so would instantly wash off anywhere exposed to water. It is also non-toxic, and burns quite cleanly. C3O3H8 + 4O2 ==> 3CO2 + 4H2O, I believe (not that combustion is one of your worries!). It would make the car even greener!
HI - jsut curious if Tesla Motors engineers could give insite as to waht they think of these videos and willit effect how the Future of Tesla and how they power future Roadsters? As well, if Tesla finds this a viable power source, could it possible mean an offshoot of the current Tesla roadster with this technology - perhaps bringing the Tesla Roadster that much quqicker into the average income range? and in general - what do you think if not going to be used by Tesla - of the following as a vialbe and seeming proven alternative power source for the future of vehicles.
Video links :
www.youtube.com/watch?v=efCelx7qe_M&feature=related
www.youtube.com/watch?v=jYcjjSfiNNE&feature=related
www.youtube.com/watch?v=dxDHGKu83v4&feature=related
www.youtube.com/watch?v=6_41btVawMc&feature=related
www.youtube.com/watch?v=Hs4GXH5Q3Rk&feature=related
thanks
chase
Oops, my little chem equation above doesn’t balance. 2C3O3H8 + 7O2 ==> 6CO2 + 8H2O. There. Arithmetic is satisfied!
Steven;
About the 4WD; I have fantasies of a motor at each end of the car, so either or both could be used at any given time. What a beast that would be!
Roy;
about PV transparency. Yes, a wee problem with having your cake and eating it, too. But Graetzel cells use the word, and I can see two ways it might apply. One is that there is more to the EM spectrum than visible light; IR and UV exploitation, e.g., would not interfere with visual transparency. The other would be if the 10% efficiency the titanium oxide films claim were “flat”, evenly spread out across the visible spectrum. That would dim the image somewhat, but might not be noticeable. The eye can compensate with subjective brightness equivalence across a huge range.
Anyway, that’s my effort to square that circle.
OT - I always had similar problems with the “invisible man” idea. If his retinas were invisible, they wouldn’t stop any light and he’d be unseeing as well as unseeable!
There is talk now of metamaterials that can route EM around an object and render it invisible. Same problem: those inside the “bubble” would not be able to use EM to perceive their environment. There’d have to be peep-holes somewhere! Which would themselves necessarily be visible. technology.newscientist.com/article.ns?id=dn9227
Incredible news.
Single gear with top speed at 125 and 0-60 at 3.9s means that barring increasing aerodynamic drag acceleration from 60-120 is the same as 0-60. I guess 10-11s from 0-125mph. That’s incredible.
Elon did say in this video: qik.com/video/22264 that you have got engine running at 20kRPM in labs instead of just 14kRPM (about at 13min point in video). Any news on that area? Will powertrain 2.0 be 20kRPM version?
Have you considered to make race-car version for promoting EV:s in some car races? AFAIK you don’t have much downforce because downforce increases aerodynamic drag and car starts to have worse handling in over 125mph speeds because of that. If you get 20kRPM version of the engine you could do car with 160mph top speed, but that requires some downforce, so less range and weaker high-speed acceleration. Maybe new batteries to get same range?
(BTW. that qik video is so good that it belongs in FAQ. Elon answers about all common questions in that video, and says something about future of the car too. AND you get some idea about how fun that car is to drive too
Hi Brian H
I’m not suggesting that it would be cost-effective for individual householders to buy their own wind turbines for their own sole use - rather that these devices would be more economical if installed as a collaborative venture between several individuals. Of course it would be better if they were included by property developers as part of an eco housing development. Alternatively the community/developer could decide that the Renewable system will not connect to any dwelling but will connect to the grid to help offset domestic consumption. The same approach could be tried with solar while we wait for nanosolar to make PVs cheaper.
In addition, in the same way that there are cheaper EVs than the Tesla, there are cheaper wind turbine designs - I happen to like the quietrevolution design. www.windpower.org/en/tour/design/index.htm
Lastly, if you choose to connect a turbine to supply electricity to a house there are a variety of solutions to the problem of intermittent/seasonal wind energy supply. A back-up generator is one.
Well done guys…..
I wish gov’s would get on board and make these cars available cheaply to the masses, or at least their technology.
I was reading in the local papers in london that they need to work on the distance per charge as these cars are great for towns and cities but powering them on longer trips is currently not viable. Has Tesla considered using aerodynamics to focus wind to an electric generator (wind turbine) built into the car to charge the batteries (much like powerboat engines but in reverse), would they provide enough power at current technologies?. If the turbines are small and powerful enough you could do away/ reduce the need for home charges and greatly increase the desirability of these cars as the public would not need to wait until the gov’s provide a power delivery system!!!!…
Remove the powers that control use…. Gov’s and oil companies all together.
The other benefits (if properly designed) to this is to provide added down force for when your cars break their current specs on speed and acceleration.
# Timo wrote on June 7th, 2008 at 4:05 pm
## Single gear with top speed at 125 and 0-60 at 3.9s means that barring increasing aerodynamic drag acceleration from 60-120 is the same as 0-60. I guess 10-11s from 0-125mph.
Timo, torque drops off at higher RPMs. Also, that wind resistance really does start to become a real factor at higher speeds. Your numbers seem a bit optimistic to me.
Brian H: The notion of a fusion powerplant costing $0.06 per watt to build and $0.002 per Kwh to operate is very appealing, but unrealistic. It reminds me of the old claims that nuclear fission energy would make electricity “too cheap to meter”. Cost claims are just wild guesstimates and are likely to be way off, considering that no fusion researchers have reached the breakeven point, none have produced useful amounts of energy, and the research fusion reactors keep getting bigger and more expensive as they inch closer to that goal.
Chase: Tesla Motors can only work with things that are readily available and on the market, they can’t wait for some wonder technology that might not be available for years, if ever. None of those “free energy” devices you linked to are available on the open market. Worse, the field of “free energy”, “zero point energy”, “magnetic motors” and “perpetual motion” are rife with self-deception, delusions, and outright frauds. There are a lot of “investment opportunities” or “dealerships” or “pre-orders” sold without the merchandise ever arriving, but the paranoid excuse for non-performance is always “sinister forces are supressing it”, and never “it doesn’t work and never will”.
BTW, the video of the “magnetic motorcycle” is actually of an electric motorbike powered by batteries. The motor, like many other motors, has magnets in it but is powered by electricity.
Chase & Rob: There is endless facination with the something for nothing concept. Here’s how it works. The something is the money investors give the “inventor/scam artist” and the nothing is what the investors get back.
Rob: This kind of topic (usually either wind turbines or alternators on the wheels) comes up nearly every single blog around here. Somehow I find them irresistible. Why not cut the wind turbine out and just run a wire from the battery to the charger so it can “charge itself” directly? Maybe power companies should build wind generators and put electric fans in front of them, in case there’s no wind! How about a wind-up toy that winds itself and never runs down? Or a ball that bounces forever?
Are we seeing a pattern yet? The frequency of these suggestions makes me concerned about the state of science education in this country. I just thought the media was being characteristically alarmist, but I’m pretty sure I could have spotted the problem with these ideas by the time I got out of 4th grade.
I love these electric cars, they are so awesome. Just an idea, what if you could create an electric car you never have to plug in and recharge? Any ideas? I have a great Think like a windmill… its so simple
I have a big fusion reactor that gives me power just about every day. I transmits the power directly to my house for a few hours each day, and I collect the power with panels on my roof. Best of all, the reactor didn’t cost me anything, doesn’t create any pollution, and lasts for billions of years. The only drawback is that it doesn’t work 24 hours a day, but hey, nothing is perfect.
I’ll let you use it too, but you’ll have to get your own collection panels.
Hunter & Roy: I am fully aware that power cannot be created for nothing, it needs to be converted from one form to another, with a loss in conversion. The question was more towards the use of turbines. On motor ways the car would be travelling at 70mph, using aerodynamics to focus and therefore increase the speed and density of the air over a turbine built inside the framework could generate electricity.
The issue is are they small enough, and could they produce enough power to run the car on motorways…. or at least charge the battery to extend its range? Its about balance, will the loss in speed due to drag/weight be acceptable compared to the gain in range????
The basic tech is there, Wind turbines are big business now but they wait for the wind to run the blades. In a car on the motorway you create the wind. Companies decide for us whether or not its viable, taking into account cost, drag and weight etc versus the power/increased range achieved.
follow on:
one of the apparent small turbines claims 14” to 18” blades (carbon fibre) several built into a shaft. And produces 200W at 20mph and 400W at 30mph.
www.speakerfactory.net/TURBINES/INNOVATIONS/BLUE/PAGES/BLUE.html
these blades would be a little large for a car but smaller blades at higher speeds could give similar results. Its a matter of cost and practicality. Using the front grill to scoop the air in and funnel it down the centre of the car over the blades to top up the battery.
Hunter:
Popeye could make his boat go faster by blowing on the sail. Are you calling Popeye a liar?
Just reading back through the post:
“Roy wrote on June 2nd, 2008 at 2:40 am
Eric Y: First there is no such thing as transparent solar cells. There is a recent news article on a transparent protective coating for solar cells. ”
Transparent solar cell are available, although new to the market, and less dependent on alignment with the sun….. ya could coat the whole car if ya want. No news on cost yet though!!!!!
www.sta.com.au/webcontent4.htm
Rob, thank you. Last night after I posted, I sort of felt a little bad for not restraining myself more in my ridicule. But no more…you’ve taken care of that. You are just like every other perpetual motion inventor….somehow they always think that if they just add enough conversion steps in there they’ll break the rules. Usually they focus on a “magic” step, which is often misinterpreted to get energy from someplace it doesn’t. In your case, you seem to think that your “wind” step somehow takes power from still air.
OK, so just to make it 4th-grade simple. Say you’re in still air. You move a car with a turbine through it at 70mph. Now the apparent airspeed at your turbine is 70mph. Where did the energy to create that “airspeed” come from? The still air had no energy to give…it all came from the batteries in the car. So you’re taking energy out of the batteries to move a turbine through air to spin it and generate energy. Now do you see that it’s still a closed system? No matter what, the turbine will create more aerodynamic drag than it will produce in electrical energy. The battery will use more extra energy overcoming that drag than it will ever get back from the turbine. Period. It’s the law.
Of course, there are those who have built EVs with turbines that they can extend while parked to top up. No problem with that, although it tends to produce very little energy.
Hi Hunter:
Your gone a little off topic!!! I’m not talking perpetual motion, don’t know why you think improving the range with other means must be an attempt at perpetual motion. The Question was at what point would it become viable…. yes there is more drag but we have the technology to reduce this effect and can reduce the drag in other areas of the car. A turbine would not run the car but merely top up the batteries a little….. so you have to ask are the associated losses acceptable compared to the added range.
No body mentioned taking power from “still air”… the battery would always run the car, but under certain conditions i.e. motorway driving could be topped up a little.
Driving at speed (from the batteries) their will always be air flow around the car… its this air if funnelled via an air ducts at the grill reducing to smaller channels that contain blades that runs to a generator which would charge a battery. As Hydro stations do, water flows over the turbine blades which drive a generator. Its known at certain air speeds with certain sized blades a certain amount of electricity is produced i.e. wind farms (not all the motion power of wind is converted, its approx 60%). Because “People” design the car we control the conditions within the car. If wind was to be captured we can control the volume on intake and by design the speed through the funnels tubing.
One example of principle
Normal power consumption at 70mph 3kW
Power consumption with turbine at 70 mph 3.5kW
Power generated by turbine @ 70 mph 1kW
So the additional power required is 0.5kW with the turbine and the power produced is 1kW then you have a gain of 0.5kW due to air flow.
It won’t power that car but adding some power back to the battery would extend it range…. so we are back to square one. It could work but is it viable???
Rob: Interesting web site. Thankyou for posting it.
Brian H. already addressed this June 7th. His point was that if your goal was not to collect all the available energy, but only partially then, yes you could have transparent or translucent panels. It so happens that most of the available energy available from the sun is in the visible spectrum (what a coincidence, nature adapted to the strongest portion of the spectrum!). In any case I have to ammend my statement and say to the extent that the solar cell collects energy (ie efficiency), that light is not passed on. Any pratical system requiring the most energy possible per unit area will be designed with non-transparent solar cells. I dont’t mean to suggest that your statements do not have validity. In a situation where you want a tinted window, it makes perfect sense to use translucent solar cells and not waste the energy normally reflected by the tint.
Rob, sorry but building several turbines on a shaft is wasteful enough to make me cringe. It’s just like the idea of vehicle drafting, the first one cuts out the usable energy for the ones that follow. However, it seems that the energy of ramming a fan through the air could possibly, make you about even energywise , at best in a nearly frictionless environment., not counting the manufacturing energy used to forge hot metal into precision mechanicals.
Then when you take the aero losses for putting a big turbine (big relative to the cross section of air your car is ramming into) along with conversion losses and the fact that have you’ve spent a lot of money to remove air that could otherwise be used for engine cooling, well, that can’t be good. Please guys can we let this one and hub motors and air powered motors die a dignified death. Yes I know air/hydraulic/ pneumatic motors are good for regenerative braking but when you already are full EV it’s a redundant system. If u really really like them look up UPS air vehicles, cool stuff, but they cant help EV’s become more efficient. Whew, I feel better now
While the blog above says that Powertrain 1.5 will retain the top speed of 125mph, the numbers don’t seem to add up. Was the tire’s dynamic rolling circumference (due to the flat contact patch) considered when choosing the gear ratio? Here are the numbers that don’t seem to add up:
A top motor speed of 14000 rpm driving a 8.2752:1 gear ratio means a maximum tire spin of 1691.8 rpm.
The 225/45R17 rear tires should have a circumference, when unweighted, of
1992.7 mm = pi() * (17 in. * 25.4mm/in. + 2*225*0.45) which would lead to a top speed of just over 125 mph = 1992.7 mm * 1691.8 rpm * 60 / (1e6*1.6093) .
A properly inflated tire carrying weight, however, has about a 3% reduction in dynamic rolling circumference. This means the top speed will actually be only 125 * 97% ~= 122 mph. Or are other factors at play?
Oops, the blog says “The top speed of the vehicle remains over 120 mph”; 122mph does meet that standard.
Ah, the blog says that “The top speed of the vehicle remains over 120 mph” and 122mph does meet that standard.
Drew and Rob: You’ve both overestimated the power produced by a small wind turbine, and underestimated the drag it would produce. Moreover, any “aerodynamic features” that would “focus” the airflow would also create drag, and the increased velocity would also increase the drag on the wind turbine. IIRC, aerodynamic drag increases at the square of the velocity, doubling the velocity means 4x as much drag.
Hypothetical example:
Normal power consumption at 70mph 3kW
Power consumption with turbine at 70 mph 5 kW
Power generated by turbine at 70 mph 0.8 kW
Power loss by adding turbine at 70 mph 1.2 Kw
This “idea” is an old one, if it worked it would already be in common use - but it doesn’t work. If we could obtain higher velocity airstreams by “aerodynamic features” with no drag, we could use it for jet propulsion and have self-jet-propelled aircraft and cars - but, of course, those “features” do create drag, a drag greater than the power of the higher velocity airstream, and it doesn’t work.
To improve efficiency and increase driving range it is necessary to reduce drag, not increase it.
Thanks Roy and Jeff….
Just in relation to other sources of power, how much power would need to be provided to make something like these panals viable? and whats the most likley technology to be used for eneregy recovery or generation?????
technology for cars is not my field of experties…..
Rob, now you’re just being obtuse. I told you why this won’t work, so I won’t repeat it. The conclusion was: “You will LOSE range by doing this no matter what, due to the laws of physics.” If you don’t believe me, ask your local high school (or higher) physics teacher. Or anyone who knows anything at all about the subject.
Rob: Those DyeSol solar panels are better than I would have thought. They claim 10% efficiency. Better than typical CIGS panels at 5%-10%, but not as good as crystal silicon at 15%-25% or indium nitride at 48%. Theroetical maximum energy at high noon on an absolutely clear day is 1kw/sq.m. If the top surfaces of the Roadster were covered in cells, then maybe 2 sq.m. @ 10% would be 200W max and more reasonably 100W average. Parked in bright sunlight for 10 hours = 1kwh. The Tesla Roadster battery pack holds about 50kwh so charge = 2%. 2% of 220 mile range = 4.4 miles. Is the cost worth it? Would you always be able to park in sunlight? Tesla believes it is much more cost effective to put the solar cells on your roof than on the car. I agree.
Thanks Roy : I was intrigued by the claim they don’t require direct sunlight, but that said if there only adding 4.4 miles after ten hours of charging, then its not worth it ( but we still don’t know the cost of them). If some day they can Provide over 25% the it may be worth looking at. I think Ireland will be using wind turbines on the house rather than solar…. unless ya can gather energy from rain fall …. were a bit restricted.
Malcolm Wilson wrote on June 8th, 2008 at 3:30 am//
===
Collaborative or not, $8.20/W installation is horrific.
CM wrote on June 9th, 2008 at 3:52 pm
Brian H: The notion of a fusion powerplant costing $0.06 per watt to build and $0.002 per Kwh to operate is very appealing, but unrealistic. It reminds me of the old claims that nuclear fission energy would make electricity “too cheap to meter”. Cost claims are just wild guesstimates and are likely to be way off, considering that no fusion researchers have reached the breakeven point, none have produced useful amounts of energy, and the research fusion reactors keep getting bigger and more expensive as they inch closer to that goal. //
=========
You clearly haven’t looked at the focusfusion.org site. All those issues are dealt with directly there. The experience of those trying for stable fusion plasmas is not relevant. Small is different. These fusion events are microns across, and self-restrained by magnetic phenomena for the microseconds necessary to produce “bursts” of energy.
FF is far closer to break-even even than Tokamak, with infinitisimal equipment costs by comparison. The whole of the research program could probably be funded on the Tokamak budget for staff coffee supplies.
Brian H. Focus Fusion and similar efforts are still very much theory and not fact. I am rooting for them, but you seem to think they are close to break-even when they haven’t started to build their first reactor. Tokamak researchers thought they were close to break-even 10 years ago, but it turns out they are no closer now than they were then.
Roy,
Another company working on transparent solar is Octillion see www.octillioncorp.com for more info
Brian H: Actually, I had looked at the focus fusion website, and I agree that it is a more promising approach than the giant tokamaks, and with a clever approach to extracting power that may be more efficient. However, after over 44 years of research, plasma focus fusion still hasn’t reached breakeven, and every step closer to breakeven requires more powerful and more expensive higher voltage higher amperage power supplies. If they do exceed breakeven, the cost will be considerably higher than predicted by early optimistic estimates, just as nuclear power turned out to be more expensive than originally estimated.
Hi. I’m writing from Barcelona, Spain. A few days ago i saw on news the announcement of this brand new kind of car tech. I’m asking myself if you’re planning, in the future, to come to Spain and open a store here? i’ll be the first one to buy a car which doesn’t need any petrol to work.
Nice work. Really pleased to see that there is still people looking in other way rather than money.
Thank you for your time.
I also was thinking about using solar panels directly on the car
. However I was thinking of using Nanosolar for all the car’s panels (roof, front and rear hood, sides - everywhere except the windows). Nanosolar claim 12% efficiency as I recall but lets put it 10%. Total surface of the car is probably around 7-8 m2. Sun will only shine on half of that so 4 m2. 4m2 x 10% = 400W on sunny day per hour which will be around 4kW per day for a 10 hour sungathering. 4kw is roughly 30km.
Now I know 30km per day is not much (and thats the max amount not average), but consider people that need only 15-20km commuting per day.
They may not need to plug in the Tesla at all except for the weekends if they are going on long trips. That I think will put people in consideration.
Now as most studies says that normal USA daily driving is about 40 miles = 64 km then if we assume Nanosolar or others double the efficiency of such technology in near 5-10 years then such solution will seem even more viable.
I proposed Nanosolar as they use thin film coating and probably with some adjustments they can manufacture entire body panels which are also solar panels
. From the videos I watched on the web their solar panels are simply some kind of ink on a metal sheet. If you then seal that with some transparent coating to preserve it then you get a cool looking black car which recharges by itself.
However I don’t expect to see such cars in near 5 years at least. Even if its possible someone have to do it first and with all research / development / test cycles its not very speedy
What is the lifetime of an batterie-stack (in km or number of charging-cycles) ?
What is the price to change an used batterie-stack ?
Have you an agency in europ ?
Rolf Moosmann, automotive-engineer in Switzerland
Behold: A game changing personal vehicle touted online by a brash startup company that has a shield-shaped logo. Specifications include a $100K+ pricetag, 300 mile autonomy, 120 mph top speed, sleek styling and cockpit appointments that will be attractive to sportscar fans … and … a PARACHUTE!
I read about this via the Register and Popular Mechanics: www.iconaircraft.com/
When I went to the company website, the resemblance to this one was so striking that I wondered if it were a Tesla spinoff or otherwise connected. There’s no direct or indirect connection that I can see, other than the all-too-coincidental resemblance of their corporate logo to Tesla’s.
Unfortunately, the vehicle is not electric. But saving the planet isn’t exactly what these guys have in mind, anyway. I wonder if they will open a chain of “stores” to sell their vehicles?
Rolf:
Battery life has been stated at about 100,000 miles before it looses performance, cost has not been stated, but some estimate $20,000 in today’s market. I would expect cost to be much lower when replacement is needed. Look at recent blogs under “feel” to get more info on their European plans.
Raw Steel: How do you figure 7 to 8 sq.m of area on the Roadster? Don’t forget that the shadey side will produce a lot less power.
Mark W: Another interesting link. Octillion says minimal loss of visible spectrum by getting most of its energy at the ultraviolet end of the visible spectrum (which glass doesn’t transmit anyway). DyeSol (Rob’s link) makes a similar claim by utilizing the infrared end of the spectrum, so maybe they should get to gether and double their efficiency!
Raw Steel: I second Roy’s question…that sounds like a lot of surface area. I did see that you cut it in half because the other part will be shaded…but the total area seems high. Also, I think 10% efficiency is still really ambitious…the 12% max they give is at the ideal angle, at which maybe 1% of the car will be. The efficiency drops precipitously as you change the angle, and the angle of the car’s surface will be all over the place. But all of this pales in comparison to the real problem: garages. You want to park your $110,000 (Wait…$130,000 after those panels) car outside all the time?
(This will not be a problem for Rob, of course, who will simply run fluorescent lighting from the Roadster battery to power the solar cells while garaged. Clever optics will “focus the energy on the panels” to increase output, enabling free recharging.)
Thanks for the link James, but I still prefer www.velocityaircraft.com
A car is a car. A solar panel is a solar panel. Put the car on the road, and the solar panel on a rooftop. Really, it will work much better that way.
Hunter all I said is hypothetical of course
.
7-8 sq meters is a guestimate of course but I think its close. If someone wants they can probably calculate it more precisely but I don’t have the time and the nerves
. Anyway you are correct about the efficiency, it will drop if the angle is not the optimal one but look at the car as somehow rounded and at any given moment the sun will shine on some of the surface at close to optimal angle. Also other sides that are not directly lighted can also produce some energy if they can extract it from refracted light (there are such solutions already)
The idea was that this should be possible in the future (I doubt it will be possible today).
When solar energy $/W is low enough as production ramps up and efficiency increases due to lot more research then we can see such solution I think.
Also if you take into account that tesla weights about 1350kg and consumes about 130W/km then if battery development progresses and lighter smaller batteries are used and other technologies to ligher the car then a 1000 kg car would consume probably 100W/km giving you even more km from the solar coating. Also , probably drivetrain, motor, tires and other inventions could raise up the efficiency in these areas too thus decreasing even more the consumption. Imagine a car like Tesla but weighting 900kg, consuming 80W/km and having PV coating that provides 7-8KW on a sunny day. That will mean about 100km
. If the battery pack holds 1000km (really advanced 
) then you might not need to plug the car at all, as during the week you will consume less than 100 and the rest will be accumulated and during the weekend you can spend the other km’s left for a vacation or trip 
Now tell me I am not a dreamer
RawSteel, obviously we weren’t comprehensive enough to deter you. You are indeed a dreamer, but unfortunately there are many more reasons your dream isn’t a great one:
First, you seem to be overestimating the available solar energy per square meter by 50% or more. According to this ( www.eia.doe.gov/cneaf/solar.renewables/ilands/chapter3.html#flat ) Department of Energy study, explained and calculated on here ( atmoz.org/blog/2007/10/15/blog-action-day-solar-power-for-the-world/ ) the total solar energy available in Tucson, AZ is 7kWhr/sq.m per day. That would mean your 4sq.m lit surface will generate 2.8kWhr (21km) at your still-ambitious 10% efficiency. And that’s in Tucson!
Then there’s the energy (not to even mention cost) payback time. It takes significant energy to manufacture PV cells, and the figures I’ve seen ( www.energy-enviro.fi/index.php?PAGE=678&NODE_ID=678&LANG=1 ) for home-installed systems suggest that it takes the panels about 2 years to generate the energy it took to make them. Since you aren’t going to have your car outside as often as your roof-mounted panels (and even when you do sometimes it’ll be in the shade), and since the car will at any given moment have very little of its area at the right angle, this payback is going to take much longer. In fact, it may bump up against a typical automotive lifespan…at which point the panels basically acted like a high-capacity, low-power, non-rechargeable battery…the factory put energy into them and you slowly got it back out. Pointless.
Also, you talk about the car getting much lighter and more efficient, but the panels will have the reverse effect. The cells aren’t weightless, and the electronics to run them and charge the pack are heavier still. I’m not sure what the total additional weight would be, but it wouldn’t surprise me a bit if it was enough to significantly increase the Whr/km. How much this offsets the extra energy given by the panels will depend on how much you drive vs. how much you keep the car in the sun, but it’s another way that your plan is overly optimistic.
Cost of course is also a complete deal breaker. I don’t think the prospect of getting 10 miles further down the road (if you live in Tucson) is going to be worth the added price. Especially when you consider that you could undoubtedly spend the same money on a rooftop system and get a way higher-output system. Since you won’t be able to count on that extra range, you won’t be planning to travel more than the battery range anyway…so there’s no benefit to having the panels on the car (instead of the house).
And since you ignored it the first time, let me reiterate the issue that is by far the biggest reason this won’t work. GARAGES. That’s where people who buy $110k+ automobiles store them. You can’t just act like they’re going to stop doing that. They’ll talk up the gimmick to their friends, but the panels won’t see the sun any more than a Porsche will.
That’s what this is: a gimmick. You see it on concept cars and Fisker prototypes and other places the marketing people need a wow factor and are willing to ignore their engineers. You emphatically DON’T see it on serious EVs. Seeing it on a Tesla would make those of us who are serious about EVs take Tesla much less seriously.
A New York Times June 14 article states that “One of the ways the authority (NYC Metropolitan Transportation Authority) hopes to improve its fuel efficientcy is through a new type of lithium-ion battery for its hybrid buses.” The article adds that the “battery” is an assembly of “…more that 2000 paper-wrapped batteries about the size of a typical C battery, stacked up in neat rows.” So, the Tesla Motors ESS concept has been right from the start. A lot of batteries, but , excuse the grammar, IT works!
This story on Market Watch ought to get the discussions rolling in here…. Seems the big 3 need incentives from congress to work on developing a battery for a car and they claim that it will not be done for years to come and never at all without millions in help for their R&D. Funny but I think this wheel has already been invented
Sometime I can’t believe their audascity !!! They say that there is no battery technology that will propel a car for more than 40 miles. Where is the rest of the world and how can they not be paying attention !?!?!?!?!?
tinyurl.com/6xmj4p
I’m just wondering if the Tesla Corp is considering a removable hard top for the roadster? It would be a very nice option.
Kevin, concerning this: “They say that there is no battery technology that will propel a car for more than 40 miles.”
The article does not say that. It says: “The first batch of plug-ins are aiming to go 40 miles without recharging — a modest but practical one, considering most Americans travel less than 40 miles a day.”
There’s nothing wrong or inaccurate about that statement. I see your main (but implied) point, which is that the big 3 are just out begging for money because they can. On the other hand, that seems to me a kind of knee-jerk reaction: government tax and stimulus policy does have very real effects on increasing R&D rates for new technologies. Imagine the economic benefit (and increased tax revenues) that Al Gore’s $600M NREN/NII programs (which really did create the modern Internet, despite all the jokes) produced…the “Gore bill” paid for itself many times over. If batteries cheap and good enough to start making a real dent in gasoline sales arrive a couple years earlier because the government spent a few hundred million, it would be a heck of a bargain. The economic impact would be tremendous, and easily outweigh the costs.
And as to your supporting idea, that “this wheel has been invented” …perhaps. But it’s still way too expensive to go into mass market full-range vehicles. And that’s what we’ll need to get off gas.
Dallas, they are not “considering” a hard top; it is available already as a factory option. Many questions about the Roadster can be answered by looking at the spec sheet. Novel idea, I know.
Kevin–
What an excellent article (not because of the amateur nature of the reporting, but because of the numerous issues it raises to the perceptive reader).
My favorite part is that the Wall Street Journal places the stock prices of the firms next to their quotes–almost as if to verify their credibility. In this case, Ford ($6.22) and GM ($14.88) are telling us that we need Federal money to help them reinvent a DOMESTIC supply of batteries (a commodity by any definition)–and even more outrageous–to retool their plants. Meanwhile, Toyota ($102.33) has been able to quickly reconfigure/retool their plants since the 1950s (that was one of the first LEAN initiatives they undertook).
I am fully aware that stock prices alone (because of splits, etc.) aren’t indicative of a company’s wealth or industry standing, but in this case, I would say it appears so.
About the 40 miles range: perhaps they’re referring to getting a GM Envoy to go 40 miles per charge (and have the same battery last 150,000 miles)? If this is the case, perhaps 40 miles range is an appropriate goal. Don’t forget, we’ll probably want an ICE engine on that Envoy just in case. Made preferably out of lead. This seems to be the proper scope and level of engineering proposed by the Big 3.
And where did the 150,000 mile number come from, Mary Ann Wright (of Johnson Controls)? At what loss of capacity? Wait a second–Johnson Controls makes batteries (Optima, Varta, LTH) and stands to benefit from any regulations transferring money from tax payers to DOMESTIC battery manufacturers . . . . What if, instead of making batteries last 150,000 miles, we let the market drive the price of this commodity item down to the point that it is feasible to replace battery packs more often? In the case of Lithium-ION, it would appear that this is starting to happen. Give it time.
One must wonder what they mean by “near-term” in this article? The way I see it, if they refer to that as 1-5 years, then their “infeasibility” arguments are moot, because a) it will take at least that long for their current batch of offerings to hit the market, and b) by their own admision, grid capacity (I assume they mean peak capacity) will have expanded to accommodate their offerings in that time.
How a Well-intentioned Government Stacks the Deck Against Tesla:
- +$30M to the “Big 3″ to fund plug-in projects over the next 3 years
- DOE incentives for “heavy duty hybrid vehicles” (what does this mean? Why not for consumer vehicles?)
Bottom Line:
According to the article, and “industry executives,” the bottom line is a policy one: whether or not Washington will make (subsidized, over-engineered, poorly-scoped) plug-ins like the “sexy” Volt a reality. It couldn’t possibly be an economics one: whether or not demand will exist for properly scoped, well-engineered, well-built electric (only) vehicles?
Hunter–
I agree with your point about the Internet; however, I maintain that the same logic does not hold for battery technology. No matter how much engineering stimulus is injected into batteries, they are (and will remain) a commodity item that does not stand to yield the same magnitude of returns offered by the Internet. Also, we must ask ourselves, what is inherently better about a battery that is made in the US vs. one made in Malaysia? I thought the current trend was to drive commodity-priced items overseas.
Perhaps it is time to embrace this logic, and instead of working to increase capacity, work on the other end of the equation: demand. If demand (specifically for Lithium-ION batteries in this case) increases by some order of magnitude, existing firms will have another impetus to compete on price and increase efficiencies in the system (e.g., production, labor, materials, and recycling). If price were to then drop by some order of magnitude, then replacing batteries at, say, 75,000 miles becomes an acceptable alternative to a 150,000 mile battery.
I realize this does nothing to address the range question, but maintain that this is where a US firm can make a difference–by engineering a better vehicle that makes better use of its batteries. Electrifying a GM Envoy is not the right answer. The Chevy Volt is not the right answer. The Tesla (220 miles/charge) is certainly a step in the right direction.
Correction: I meant to say, “. . . instead of working to increase longevity . . . ”
My secondary point is that capacity is already sufficient.
A little comment about range vs weight. Since and electric car such as the Roadster can recover momentum energy through regenerative braking, the mass or weight of the car has much less effect on range compared to an ICE. There are still desirable benefits of low weight. Less weight means better cornering, and smaller tires are required which leads to less rolling resistance.
Has Tesla Motors consider creating an electric motor for General Aviation (GA)? Considering the performance and innovation of the Tesla, at first glance it seems the technology is there to produce electric motors for small GA aircraft (100 - 150 HP engines cruising at about 2500 rpm).
Thanks,
Dan
Our newly elected Australian labor government is handing over $500 million taxpayers money to Toyota to build Toyota Prius hybrids in Australia. The majority of the Australian people would prefer our hard-earned tax dollars to have Tesla Motors to produce a 100% electric vehicle in Australia, as our state and federal governments have a 38% tax on fuel plus 10% GST tax, these rip-off taxes on fuel Australia wide earn the Australian Government billions, it is a conflict of interest for our ‘democratically elected’ government to hand over $500 million to Toyota when companies like Tesla Motors has products with a very low carbon footprint once manufactured, plus the additional benefit of ridding the Australian people of rip-off fuel taxes. Our government still has $435 million to hand over to Toyota maybe Tesla Motors could present a public submission to our government and people to show what Tesla could do with this kind of incentive. Please help us!!!.
Darin,
Why do you say the Volt is not the right answer? Of course I love Tesla’s solution but it results in a car costing $100,000. Chevy could easily produce a car with say a 100 mile, or even 200 mile, range but they couldn’t sell it because the battery cost alone would take it out of the reach of their customers. The Volt is an intelligent compromise. It has sufficient range at 40 miles or so to satisfy the daily needs of most drivers. It’s just about cheap enough to be afforded by most drivers of new cars, given the savings they will make on fuel costs. The only need it doesn’t satisfy is that of the regular long-distance driver. For that kind of use it isn’t going to be the best vehicle. For occasional long-distance drivers the Volt will still represent a good option. The savings you will make on your regular short trips (40 miles and under) will more than compensate you for the slight additional fuel cost, over a very efficient ic car, on your occasional long-distance drives. If the car performs as advertised I’d buy one and laugh all the way to the bank! As a series hybrid it runs on electricity all the time so it is surely a good first step towards the affordable BEV that we would all love to see on sale now. As batteries improve and get cheaper the ic generator in Volt-style cars will get smaller and smaller until it eventually disappears being totally unnecessary.
Dan,
I’m sure Tesla could easily produce a motor that was suitable for General Aviation but what about the battery? Weight is so critical in small aircraft……all aircraft really…..that a Tesla-style battery would be way too heavy. Then there’s the issue of what happens when the battery runs flat. You can’t just coast to a halt in a plane and call Tesla for backup. So you’d probably need a generator to keep the battery charged up and then what you have is a flying Chevy Volt. This might work out in future as batteries become ever more efficient and come down in price but I doubt that the equation works out favourably at the moment.
I still think the easiest way to adress the range issue would be to standardize batterypacks, so they are easily replaced, like Project Better Place suggests. Of course, I hope Tesla will be the first to make a standard module for their range of vehicles, this way, you could be in the lead partnering with electricity suppliers for a standard suited for your vehicles.
On a sidestep - If I drive a Tesla, constantly shifting between accelerating to near topspeed and braking to low speed, what would the range of the current batterypack be, full, half, quarter range? How much stress would this put on the cooling system and how much energy would you be able to recover from regenerativ braking? If you found an easy way to swap batteries, would you be able to take part in Endurance Races?
Obviously, I’m asking because of the newly finished Le Mans Race (and our man, Tom Kristensen - The Humble Great Dane, won for the 8th time - I live less than 20 miles from his town of birth) and the Aston Martin Racing Team - 009, who where the ones with the least pit stop time, drove less than 110 miles/fillup on average (guessing they got a fillup every time they went into pit), and they wouldn’t (obviously) be able to recover any energy from braking. However, they needed less than 30 minutes to do 28 pitstops… You need a fast changing (and charging) batteryswappingstation.
Oh, forgot - you need another gearbox too…
One of the other things that is getting glanced over quite a bit from this article is the 150,000 miles that they want to get out of a battery. Can anyone tell me why this is so important ????? Do people really keep their cars for 150,000 miles these days any way ? Sure there is some demand for used cars now but even so MOST people do not buy used cars with over 100,000 miles on them anyway right ?!?!?!?! Average American owns their car less than 5 years so that would be like 75,000 miles give or take. Why are we doubling that for BEVs and not ICEs. Seems to me that the standards for BEVs are being made out to be double what they are for ICEs in almost all cases. People also complain that a BEV takes some carbon to run because of fuel plants needed to supply the electricity. Even if that is true - which it is for the time being - they still burn less than what it would take to run a less efficient ICE all of the time. Seems that BEVs need more range than an ICE as well to be sucessful. Many people are saying that they want a BEV with a range of 400-500 miles. I know of no car that can do that on a tank of gas. Also we have the speed issue to overcome. We need BEVs that can do 100+ MPH ?!?!?!?! Why the legal limit is 55-65 in most places except for a few rural ones that may get up to 75. I am just curious as to why all of the double standards. Also, why they need all this money for R & D when the technology is ALREADY on the market!!!! We have Roadsters already. Granted that more research always help to drive the prices down and increase efficiencies and is a good thing BUT why not hit the market with what you have and build on it. Why do we need to come in at the top of the market. It has taken 100 years to get the car where it is now and 100 years from now the BEV will be the same dinosaur !!!
Why are all of the MAJOR manufacturers able to develop all of this technology BUT the big 3 in the US. How come no one needs help but them ?
Darin Ladd, I’m not suggesting that the battery industry itself will be the big economic benefit. I’m suggesting that having better batteries will let us use cheaper energy sources than oil, which would have a huge impact. The commodity nature of the batteries that would be developed would help, not hinder that goal. If America got one extra year of transportation from the grid instead of oil, we would save billions. So faster battery development does have potential for major impact.
I do agree that it probably wouldn’t be “as big” an impact as the Internet. But then, what would be?
Kevin Harney, are you kidding? I’ve driven my last two cars about 185,000 miles each, and they were still running fine. The people I sold them to will get at least another 50,000 miles out of them. I know lots of people who run their cars for well over 200,000 miles. I don’t think you can expect folks to just throw away a car at 75,000 miles.
Kevin;
one item from your mishmash of actual and rhetorical questions: the range thing is because of the the time required to “refill” and the ease of locating a fill-station. Gasoline is fast and easy, so range isn’t so critical. When filling is slow and hard to arrange (on the road), you need more slack.
Andrew Kelsey–
My personal opinion is that there is currently a market for a $20,000, 40-60 mile range, Chevy Volt without an on-board generator. The generator is wholly unnecessary. Otherwise, your point that the Volt as it is currently planned represents a medium-term compromise (and is better than a non-plug-in hybrid) is well taken.
Hansen–
Your idea of swappable packs appeals to me immensely. I wonder if there won’t be a way to swap out *part* of a battery pack in the future–that way, cost per change-out is kept reasonable, and overall performance in the 75,000-150,000 mile range does not suffer greatly. Obviously engineers would have to conquer the problem of battery management to a) over-use some of the cells from the beginning so they begin to fail in a progressive fashion, and b) keep older batteries from scabbing off the newer batteries. If it were possible to design a standard form-fit for these devices (i.e., interface control standards), newer technology could be loaded in the same box and substituted for depleted batteries. Again, the battery management system would have to be programmed to take upgrades into account.
Hunter–
You are right: higher capacity, longer-lasting batteries are one significant front in the struggle to reach market saturation with electric vehicles. I think there may be other alternatives (more near-term) that are a better use of energy/policy, because they will have near-term benefits.
I think Kevin Harney augments my point that it is not necessary to address the technology equation right now (i.e., capacity and longevity of batteries). If Federal money is to be spent, why not spend it on increasing demand for existing batteries, e.g., better incentives for consumer purchasing of electric vehicles (note: I do not recommend this, but only point out that it might be a more efficient use of the same money)? I’ll skip the formal proof, but will assert that the associated price drop in Lithium-ION batteries might be worth the effort. Especially if battereis represent such a large percentage of the overall vehicle cost. It might also open up a whole new realm of possibilities for how electric vehicle batteries are treated.
Thomas J,
OK now you are the one being unrealistic. I never said that there were NO cars out there that went more than 75,000 miles what I said was that MOST people do not drive them that far and that MOST people do not buy used ones over 100,000 miles. National average for owning a car is something just slightly shy of 5 years and I think it is closer to 3 yrs than 5. And I certainly am not saying that it be thrown away !!!! It is traded in and that is how we get a used car market. What I was saying is that those cars with 100s of thousands of miles USUALLY are on the 2nd or 3rd engine. People do not baulk at replacing an engine why is a battery any different ?
Brian H,
This is true. BUT again with MOST people the daily distance is not more than 200 miles and further more the daily distance for 99% of the people is less than 25% of that distance. Why do we have to have a car that will drive ALL day without stopping?!?!??! 400-500 miles is 8 hours non stop at highway speeds
Who would ever WANT to do that in reality ?
All I am saying is lets make the playing field more level and realistic. BIG 3 are making this into an VERY unfair game.
According to Kevin Harney…
“Many people are saying that they want a BEV with a range of 400-500 miles. I know of no car that can do that on a tank of gas”.
Really? My Prius holds 9.5 gallons and typically goes 410 to 425 miles per tank.
GREAT!just a thought. in the future whenever that be. how about utilzing Tsla radient energy embedded in roads. to wirelessly when possible supply eletric current to the motor? July 10th is Global Energy Independence day teslas birthday as well!
Is Tesla Motors, Inc. going to manufacture a sedan version, semi truck version, pick up truck version, mini van version, and a motorcycle version of electric power transportation?
I am an avid car guy. I work on, recover, and customize the automobile. I am interested in all the aspects of electric cars. And I’ve discussed to people about building a self effiecent electric car. One that has its own power souce. Conbustible engines use alternators or generators ran from the pulley system to keep the power supply to the battery or batteries, without this the engine would not run. You need power for spark. Why can’t electric cars use an alternator or generator to help keep the batteries charged for maximum range of operation. If the engine is running it can be producing electricity to rebuild its stored power.This is the reason people are afraid of electric cars, they are worried the electric car will not keep going if they want to travel long distances. I drive 600 to 1000 miles at a time. I need a vehicle that can last long ranges, not just spurts of range between charges. If this sparks an interest please reply.
The 256 mpg equivalent value posted on your homepage is for the American gallon? Am I correct to assume that it has jumped from the previous 135 value due to careful re-calculating and the new drivetrain? If so, the Imperial equivalent will be 307mpg!
WOW!
OK guys, I’m new to this site which I guess makes me as Carlos Mencia would say, dee dee dee. I respectfully am asking advice on which curriculum to enter as I am reurning to college. Iknow Tesla will eventually come to Chicago and I would love to be a service engineer. I don’t want to end up with another useless degree like I did with psychology. Any help would mbe greatly appreciated. Thanks for taking the time to read this otherwise useless blog.
Kevin, you say, “Average American owns their car less than 5 years so that would be like 75,000 miles give or take.” While this is true (according to DOT the average driver trades in a car after 4.5 years and 41,000 miles), given that almost all cars end up having more than one owner it’s the wrong metric. The per-car lifespan (as opposed to how long any particular person owns said car) is what we need to be looking at, and the average there is about 100,000 miles over ten years. Furthermore, the design life of cars from major automakers is usually 150,000…which starts to make that quote (from an employee of a major) make a lot of sense.
I’ve had my ICE car for 9 years, it has 140,000 miles on it (24,000 of which were there when I bought it), and it’s not nearly done.
June23,2008————————————————————————————–
Gentlemen: The info mentioned in the web site above goes back even over two decades. For the electric powered car to become a success an infrastructure is required where all should participate. As mentioned in it, what is required are swap battery stations owned by companies such as General Electric Co., Saft, Etc. and others such as present gas stations ready to make the transition progressively to battery exchange systems ( I can design them if need be.) What is required are standard battery sizes and voltage …interfacing methods between the car and battery transfer from storage and recharging stacks. Other considerations should be taken to permit in the near future the adaptation of the vehicles in in a global high speed network…..which can be didcussed with all nations soon. For more visit this main website — trillions.topcities.com
Sincerely Jack marchand
“Tesla is also hard at work on model 2, the mid-size luxury sports sedan, which will be unveiled in the first half of next year.”
–Elon Musk, 2007.12.21 www.teslamotors.com/blog2/?p=54
Whoohoo! 7 more days till Whitestar info!
–Hunter, 2008.06.23, www.teslamotors.com/blog4/
I have a problem with the quotes MPG on you website. You claim a range of 220 miles. You claim an efficiency of 90% You claim stored energy of 50 kwh. therefore you needed 55 kwh from the grid to go the 220 miles. 55 kwh is 187,660 BTUs. A gallon of gaoline has 115,000 BTUs LHV so you need 1.63 gallons of gasoline if the electricty was generated at 100% efficiency. This mean with no entropy in the electricty generation you at best get 134.8 mpg not the 256 mpg you claim. If the electricty is generated in a state of the art combined cycle power station that is 55% efficient your “real” mpg is 74.14. Please contact me so we can discuss this
Lindsay Leveen The Green machine
John McCain is lucky, but under-informed. If he becomes President , the U.S. Treasury would not have to hand out his proposed “…$300 Million Prize for a Next-Generation Car Battery” (part of June 24 New York Times headline), because this “battery”, the Tesla Motors ESS, already exists. Of course, if McCain’s offer is somehow deemed retro-active, Tesla should go for it..
Darrin - Look at Project Better Place’s site, I think you’ll find it interesting. By the way, I’m one very exited Dane.
To Lindsay leveen,
This issue has been extensively discussed on the owners website, but since you may not have access to that, I’ve copied one excerpt from an engineer at Tesla that addresses your concern:
Hi everyone,
Zak asked me to jump in here since I’m the engineer responsible for EPA range/efficiency testing and generating the MPG data.
The EPA MPG calculation is specified in the Code of Federal Regulations, section 10 part 474. This regulation defines an equivalence between gasoline and electricity of 82.049kWh/gallon. frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=2000_register&docid=00-14446-filed.pdf
You can then calculate: mpg = kWh/gal / kWh/mi = 82.049 / 0.321 = 256mpg
The 0.321kWh/mi value comes from our range testing that is certified by EPA. However, as Zak correctly noted, the EPA has not had a current procedure for EV testing since 2003. Instead, EPA defers to the procedure specified by CARB, which is the Society of Automotive Engineers recommended practice “SAE J1634 Electric Vehicle Energy Consumption and Range Test Procedure”. This procedure uses a chassis dynamometer, and a paraphrased version would say 1) start with a fully charged battery, 2) drive the vehicle over the test cycle until empty and measure the miles driven, and then 3) recharge the battery to full and measure the electricity used.
From our latest testing, the results for city/highway cycles were range of 231/224 mi and electricity use of 0.316/0.327 kWh/mi respectively.
As defined by EPA, you combine the city/highway data using a 55%/45% weighting: 0.321 kWh/mi = 0.55*0.316 + 0.45*0.327
So the MPG number depends on what equivalence you assume for electricity -> gasoline. There are many approaches to this, each with their pros and cons. Some people think that MPG is meaningless for EVs, but there are many others who want to know what the number is. Tesla has decided to quote the mandated EPA 256mpg number. The 135mpg value is an outdated non-EPA estimate, and I’m sure we’ll be updating the website soon.
thanks
Andrew Simpson
Posted by AndrewS on May 22, 2008.
So, that from Andrew Simpson. Also, please be sure to read the footnotes on the Tesla Motors home page, that also explain how the MPG figure was calculated.
Howie, I think McCain is looking for “even better” batteries. Aren’t we all. I dare say once the actual legislation is written (if it ever is) the qualifications will be clear. Not that I think this is good policy; if the government is going to spend money in this area, I’d rather see them actually fund research. You have to try a lot of things to get a breakthrough…just paying the team who finally runs into it (and at the end, when they can’t use the money to pursue it) doesn’t seem like the effective way to get it done.
Lindsay Leveen, welcome to the blog. I’m sure your expertise will be well valued here. I think I can explain the disparity you see:
The 134.8mpg number you come up with is strikingly close to the old ~135 that Tesla used to claim based on a “simple math” approach. Presumably, they did the same calculations you show. However, had you looked at the bottom of the page (since there’s an asterisk next to “256mpg equivalent”) you would have read the following:
“Conversion from electric consumption to gallons of gasoline equivalent is calculated using the Department of Energy equivalence factor documented in the Code of Federal Regulations, Section 10, Part 474.”
So, first off, you can’t blame Tesla for using the official formula; your quarrel is with DoE. Obviously DoE’s formula does not just swap BTU for BTU. I suppose your next question is “why not?” …and my response is “why would you?”
I understand your method, and it’s accurate as far as it goes…but the question it answers is a physics problem, and the question DoE wants to answer is an economics problem. I suppose this is a natural consequence of your extensive chemical engineering background…the DoE numbers are for the customer, not the engineer. The whole purpose of DoE’s mpg rating is the “window stickers.” That is, they are designed so consumers know how much gas (money) they are going to put in a car to drive around. The consumer doesn’t need to know how much energy went into each mile…he needs to know how much he’s going to be paying at the pump for each mile.
When you look at it like that, it’s easy to see why the formula isn’t equivalent on an energy-usage basis. Getting your BTUs from the grid is way less expensive than getting them from oil. A consumer comparing mpg ratings is actually trying to compare fueling costs, and 256mpg is a much better approximation than 135. In fact, it’s still way low…I’d guess the conversion factor was set back when gas was a lot cheaper than it is today. Personally, I think the stickers should have a “fuel cost per mile” rating, based on annually-updated estimates of gas and electric prices. Then they could quote the mpg for gas (gaz?;-) ) cars and the Whr/mile for EVs…no need to convert, since the cost-based version is always in dollars. That way they would satisfy both the customer and the engineer.
So, my point is not that the energy-based method doesn’t have its place. I just think that place is in technical discussion, while the window sticker (and the website front page) is the domain of the cost-based approach.
Also, you’re being unfair when you claim that the “real” mpg is 74.14 because of power generation losses. This is the “well-to-wheel” efficiency, and I agree that it is the most accurate description of the system efficiency. But the ICE mpg ratings are pump-to-wheel, not well to wheel. So they aren’t “real” by your definition either. If you want Tesla’s number to be 74.14, then you need to multiply all ICE ratings by .817 to get the well-to-pump losses in there. See www.teslamotors.com/efficiency/well_to_wheel.php
SteveF;
Excellent info update, thanks for that.
Lindsay Leeven: Re MPGe calculation.
The main point of the DOE “conversion factor” is that it is not based on physics, but has a large “incentive factor” to persuade automobile manufacturers to convert to alternative fuels including electricty. From the link provided by Steve F.
“DOE invested considerable time and effort in attempting to develop a method that could rigorously account for the advantages to the Nation offered by electric vehicles compared to conventional vehicles, but was unable to identify a method that was sufficiently objective, robust, and consistent with established policy directions.
Thus, DOE stands by its proposal to provide electric vehicles the same reported-fuel-efficiency incentive (the 1/0.15 factor) that other alternative fuel vehicles currently enjoy.”
Cents per mile is the only reasonably stable measure. Then, if a customer says, “OK, I pay $4 and get 40 miles, that’s 10¢ a mile for a 40 mpg car. That 10¢ would get me 5 miles, and the $4 would get me 200 miles, so the Tesla is a 200 mpg car.” And as the price of gas rises, so does Tesla’s mpg rating!
I am a simple guy who believes in the first and second laws of thermo. The DOE Department of Entropy says there are 82.049 kwh/gal of gasoline this means they have gasoline with 280,000 btus per gal. This gasoline does not exist. but if it did my C280 Mercedes would get almost 60 MPG. Second Tesla claims a kwh per mile of 0.321 The battery charge to discharge cannot exceed the 54 kwh of total charge. Let’s say we use 45 kwh between charge and discharge so we get a range of 45 / 0.321 or 140 miles which is far less than the claimed range. Am I missing something or all of these claims the new third law of thermodynamics. The Tesla vehicle is wonderful, it is fast and it is clever and points to the future. It gets approximately 75 MPG when electricity is generated in state of the art combined cycle natural gas fired stations. It gets 44 mpg when electricity is generated in simple cycle power plants. Let’ s obey the laws of thermodynamics. Tesla does not have to quote the Department of Entropy. They are the guys who gave us hydrogen, bio-fuels, MTBE and $4.75 gas in California or Kaallliffoorrniaaaa as the dumbest governor of all calls our state. For the truth abot green energy go to www.greenenergyexplained.com
Andrew, Hunter Et Al.
If I was to buy a vehicle based on cents per mile I would buy a used Ford Escort as capital amortization costs and replacement of the battery pack will far exceed the cost of fueling the lowly Escort. The only way to make an apples to apples comparison is to compare grams of CO2 emitted per mile traveled. Andrew has given us the figure 0.321 kwh per mile. The average emissions in the US to generate electricity is 1.4 pounds of CO2 per kwh based on the mix of generation sources. Therefore the Tesla emits 0.321 x 1,4 x 454 or 204 grams of CO2 for each mile travelled. Let’s go back to the lowly Escort that gets 30 mpg. A gallon of gasoline has a mass of 6.3 lbs. Gasoline has 2 hydrogen atoms for each carbon so gasoline is 12/14 carbon or a gallon of gasoline has 5.4 pounds of carbon. Carbon dioxide is 44/12 as heavy as gasoline so a gallon of gasoline equals 5.4 x 44/12 pounds of carbon dioxide or 19.8 pounds. The Escort has CO2 emissions of 19.8/30 x 454 grams per mile or 299.6 grams of CO2 per mile. The Tesla has 32% lower carbon foot print than an Escort. Now let’s compare the Tesla to a Prius that gets 50 MPG. The Prius has CO2 emissions of 179.8 grams per mile or 12% lower than our Tesla. This is the only real comparison to make. It is time for Tesla to update the website and admit that if a Prius has a size 8 carbon footprint the Tesla has a size 9.
always go to www.greenenergyexplained.com
Lindsay Leveen The Green machine
I was at a luncheon last week and mentioned the Tesla Roadster and how great it was to have a production electric car with a single charge range of 200+. I explained about the Roadster and how it is leading to a mid-sized sedan. I pointed out that it would be used more like your cell phone in that you would plug it in at night instead of always running it low and filling, like a car. A couple siting at the table dismissed it immedialely, “How would you ever take it on a trip?” I happen to know they have an SUV and a Sedan, so if the keep either of them it could be used on trips. The other simple answer is to rent a car for the family vacation, many do anyhow!
I have always hated hybrids, making a complicated gas car more complicated by adding electricity and doubling the maintenance is crazy! The answer is 12 moving parts… Way to go Tesla, you Rock!
Will tesla ever make an electric car with a large hook which you deploy from underneath the car to latch on to the truck you are tailgating so you can recharge it using the regenerative braking?
Dankoozy;
Nah, they’ll just use a magnetic field to pull the car along against the resistance of the regen brakes. That way it can be turned off in a millisecond.
Being the Teslas is so cutting edge, why hasn’t Tesla incorporated the tweel is its design?
So any weight difference between 1.0 and 1.5? If so, will it affect the balance of the car?
I’d forgotten what the tweel was. Had to look it up, good idea, although being Canadian I think it should have sidewalls to keep out snow and ice.
orwell;
maybe because at high speeds, the tweel shakes, howls, and heats. ‘Tweel be a weel before it’s reedy for Tesla!
I know that the car is extremely quiet on the outside. How quiet is the interior? Please compare the experience to other fine and performance cars (i.e. Merecedes and Porsche). Thanks!
e la possibilità di utilizzare un motore magnetico invece che elettrico…..?
…..non conosco l’inglese mi dispiace
….mi chiedevo se invece di usare un motore elettrico non fosse possibile sfruttare l’efetto calamita dove i poli uguali si respingono e utilizzare l’energia solare per alimentare le elettrocalamite ma abbattendo gli atriti…..
….o sto dicendo una cavolata?
….comunque mi piace molto anche se non potrò mai permettermela….
…ciao
IS IT POSSIBLE ? What would happen if your company could incorperate a hood scoop on top or under your car? While traveling down the road the wind hits the scoop which hits a fan which turns an alternator which charges a battery or a 2nd set of batteries. Charge the 2nd set while you get the 1st 200 miles out of the 1st set, flick a switch on the dashboard when your 1st set runs low which would turn over to your 2nd set while charging your 1st set. Never have to stop at a gas station or a hydrogen station ever! IS THIS POSSIBLE?
TESLA Motors:
Has anyone considered the future possibility of coating entire cars bodies with spray-on plastic nano-photo-voltaic paint? Combined with vastly improved batteries, the captured solar energy could power a vehicle all day and all night as well. That would eliminate the need to recharge overnight. While spray-on photovoltaic paint is still experimental and an estimated 15 to 20 years away, massive financial backing might shorten that period. I know I’m thinking out of the box here, but it is not mere science fiction. For examples, click and read the following:
www.forbes.com/2004/10/21/cz_jw_1021soapbox.html
news.nationalgeographic.com/news/2005/01/0114_050114_solarplastic.html
www.halfbakery.com/idea/Photovoltaic_20Paint
If the idea works with clothing (to power cell phones), why not with autombiles, trucks, buildngs, and many other applications? THINK BIG!
David S. Johnson
Port St. Lucie, FL, USA
Ok, I seen it, the Roadster on cbs with Harry Smith, can’t afford it cause I”m disabled vet but have a 89 red vette, can you retro fit ????? The motor is the size of a watermelon?? How long do the batterys last? and what do you do with them when worn out??Thanks, beautiful car, if my name was Jay Leno, I’d have one but my mom named me Tom, Haha, thanks for helping save my Grand kids.. “Fish”
shawn worster: This gets suggested about every week on this site. The extra drag induced will cost more than the energy produced. It is not possible.
David S. Johnson: Painted on solar cells is also frequently talked about on this site. Most of your info suggests 15-20 years away. When this is pratical and cheep Tesla (and others) will do it. They won’t waste any time on it in the next few years.
Have you considered quick charge packs that are spread out throughout the states that could recharge the battery in less then 15 minutes? But this can only be done if you add ceramics to the battery packs which would allow them dissipate heat very fast, other wise the life of the battery may decrease or it may cause them to burn out.
Have you considered quick charge packs that are spread out throughout the states that could recharge the battery in less then 15 minutes? But this can only be done if you add ceramics to the battery packs which would allow them dissipate heat very fast, other wise the life of the battery may decrease or it may cause them to burn out.
Is it possible that you would be adding solar panels to the roof of the car so that it could recharge will not a places that do not have access to outlets?
Will you be building an assembly line like the major automakers? Which would drive down the price of the cars so that anyone of any income level can buy your cars?
We will never again see an all electric can in this country produced by the major Auto manufacture companies again like we did in 1996, because they know that they can not make as much money as they do with internal combustion engines. The major auto make got together and took back the cars that they had made from the people that had them, and then they crushed the cars and shredded the cars so that the American people would not know about the cars that could free us from foreign oil in 2004 they destroyed all the electric cars!
So it is the plan of the Oil companies and the Auto companies to never bring back a 100 percent electric car even though we have the technology to produce electric cars with over a 400 hundred range right now, because the automakers sell so many after market parts and do so many repairs to the cars we use today. The automakers do not care about the environment or gas prices because they will lose money if Americans become energy independent by having its people drive all electrics cars. So they came up with the idea of making hybrids so that they could still keep us on oil and so that they could still sell their parts to cars!
I hope that the company becomes a major automaker and shows the other automakers, that they missed out on a great opportunity by casing electric cars away!
Shawn Worster: No, it isn’t possible. You’ve overlooked the drag produced by a hoodscoop and fan, which causes the motor to work harder and draw more power from the battery. You’ve also wildly overestimated the power generated by a small windmill - it would be much less than the additional power needed to overcome the drag! It would actually reduce the driving range! You aren’t the first to suggest it, perpetual self-powered recharging schemes are common, but they just don’t work.
David S. Johnson: “Spray-on” solar cells are still a lab curiosity and are not on the market. They would have to be proven cost effective and reliable before being considered as a car finish, and that hasn’t happened yet. Tesla Motors has to work with what is available now, and cannot wait for some far future product to arrive.
Thomas Fisher: Sorry, Tesla Motors is too busy with the Roadster and designing their 2nd model to do EV retrofits. There are other companies that will do it for a substantial sum, and there are EV parts suppliers for the “do-it-yourself” EV retrofits. I’d suggest doing a bit of study and research on EVs first, then if the cost and technical challenges don’t scare you off, go for it!
Babelfish translation of Michele, Italiano to English “and the possibility to use a magnetic motor instead that electrical worker. ….. I do not know English me dispiace ….I asked myself if instead using a electric motor it were not possible to take advantage of the efetto magnetizes where the equal poles are rejected and to use the solar energy for feeding the elettrocalamite ones but pulling down the atriti ones ….. ….or I am saying cavolata? ….however it appeals to a lot to me even if I will not be able to never allow it to me….” Bablefish is less than perfect, but I think I’ve got the gist of it.
Electric motors use magnetic fields switched on and off to work. Magnets by themselves are too limited, repel once, then you need effort to push them back. Like coiled springs, you can only get out the energy you put into them. Solar cells are expensive, and do not produce enough energy to be worth the cost.
babelfish.yahoo.com/translate_txt Inglese di traduzione di Babelfish ad italiano. Spiacente, I don’ la t parla italiano. I motori elettrici usano i campi magnetici commutati in funzione e a riposo a lavoro. I magneti da soli sono troppo limitati, respingono una volta, quindi voi sforzo di bisogno per respingerli. Come le molle elicoidali, potete uscire soltanto l’energia che mettete in loro. Le pile solari sono costose e non producono abbastanza energia per valere il costo.
How about putting together a Model T concept for us poor folk who would love to get off oil? A Henry Ford innovation that could make this vehicle available to everyone? Given my life tsyle this vehicle would handle all of my needs and I wouldn’t need any more gasoline except for my lawn mower….you could probaly fix that too!
For those who are interested in owning a Tesla Roadster of their own right now, check out your local Wal-Mart (or other toy store). Unexpectedly, they sell an electric blue model for about $0.97.
For more information, see: www.hotwheels.com/cars/2008/cars_mainline_models.aspx (First column, sixth row)
Kevin Flynn,
TM has announced that your Model T will be out within the next 4 years. And there are already battery powered lawn mowers so you can buy that now !!!! LOL
I hope you come to intergrate capacitors for mass energy storage, this would greatly reduce the time it take to recharge the car down to 15 minutes, once you have that breakthrough you will completely blow the major automakers away!
Kevin Flynn: www.teslamotors.com/blog2/?p=8
Electronics is my profession. Have had a lot of experience with building electronic test stations and others. Worked with switching power supplies that supply high voltage. This information I am reading is very interesting. 850 Amps, and New bipolar transistors.
I have a lot of ideas that popped into my head that could be of help to Tesla motors. Would like to become an employee in San Carlos to help the Tesla Team to build the best electric car in the World.
Thank You
David Bonzani
Purnell: I noticed that you posted the same statement on Think, and it has been answer there. I will add that Phoenix has allready proven a 10 minute charge time, it is certainly possible. But the logistics of safely handeling hundreds of volts at hundreds of amps is a daunting task. I have not found any plugs on the market to handle such a load, and the (2 to 4) cables would each have to be almost as thick as a gasoline hose. I assume Phoenix proved their capability with bolted connections and not a plug. But over-night charging is easy and convenient. When battery technology improves to the point that you can drive all day without worry, then the need for fast charge stations will disappear. The question is will it take long enough to develope these new batteries to make installing thousands of quick charge stations profitable?
To allow Powertrain 1.5 to propel the Roadster over the “magic” 200km/h, perhaps the actual motor rpm limit will be raised by 2% to 14300 rpm.
Mark: That may already be possible, in some places I read top speed of 120 mph and others 125 mph. I don’t know which is correct. In this blog it just says “over 120 mph”.
infortmative insightful and excitng electric cars are not just golf carts they are legit means for speed freaks and car enthusists tree huggers and.. gas misers pretty much.. everyone
perhaps tesela will team up with one of the big car companys and make a slightly more afordable car for us all to enjoy
it givesu guys more cred more experience and more capitol ..for bigger and better roadsters heh
just a thought
Mark;
[Now you’ve done it. The secret is out - ed]
No, there’s a little wind turbine hidden in the front grill to take advantage of the free airflow there and generate power which is routed to a small propellor venting through the rear bumper which pushes the car that extra 2%. But don’t tell anyone - it’s top secret!!
I noticed the TE curve published for the motors system has a linear drop in torque instead of a 1/x drop past base speed. This leads to a roll off of power.
Are you working on field weakening methods to keep a more constant power past base speed?
We need to electrify our highways in a similar manner as we have the Amtrak Acela.
Electrifying the highways will allow all-electric cars to be recharged while driving.
The vehicles will use their own batteries to get to and from the highway.
While on the highway, the vehicle will draw electricity off the grid in order to power the vehicle and recharge the batteries.
Has Tesla ever looked at Enova Systems in Torrance,Ca. as a resource for mass production and/or problem solving ideas?
An bit off-topic question. If there was an electric car made specially for drag-race purpose with a high budget given, could it outperform even the best internal combustion engine drag cars?
Ric_lv: I believe strongly that soon you will see electric dragsters out-performing the very best nitro-fueled dragsters. Advances are being made in motors, electronics and batteries at a rapid rate so it is now possible to get the required power. Since the torque on an electric motor is precisley controllable you can have the ideal minimal tire slip maintained throught most of the distance, and it is this edge that will make the electric superior.
Ric_lv: If you want to talk about details, click on my name, scroll to the bottom and send an email to contact.
Ric_lv, not only are there electric cars made specially for drag racing, they even have their own organization - the National Electric Drag Racing Association! See:
www.nedra.com/
And yes, they are really close to taking the title from the gassers.
Hi Ric_lv
Check it.
www.plasmaboyracing.com/whitezombie.php
www.killacycle.com/
Have you concidered a beefed-up version of a continuously variable transmission (CVT) that several auto makers are now using?
mroman: Never! Read this blog. It’s all about how Electric Cars do not require multispeed transmissions.
I see that JB Straubel will be one of the panelists at a breakout session during Plug-in 2008, this Wednesday in San Jose. Good luck with the talk, JB, and please blog your presentation and as much material from the ensuing Q&A, if any, as you can.
I was reading press promotional material about this event, and was amused to see “experts” declare that “LiIon is almost there,” except for problems of overheating, cost, and component lifetime (which those quoted expressed confidence “would be solved” soon). I would be interested in seeing some of the questions you get, and whether you experience the urge to “beg to differ” with the pronouncements of others on your panel. I wish I could be there, but have a previous engagement that day, alas, so I hope you can share some of the experience with us here.
And to add to what James said above (urging JB to give us an update on Wednesday’s panel session), how about an update from some of you Tesla folks who have driven the Roadster with the 1.5 Powertrain? What were some of those experiences like? I’ve heard that Zak came back after the first time driving it “with a big smile on his face”, but I know more of you at Tesla have driven it. How does it compare to 1) the cars some of us have driven that were locked in second gear, and 2) the two speed powertrain that preceeded it? Hoping to get a vicarious thrill from your comments (while I wait for my car), since the few tidbits I’ve heard so far are that the actual performance of the 1.5 Powertrain is amazing.
Thanks!
www.detnews.com/apps/pbcs.dll/article?AID=/20080722/AUTO01/807220364
Gentlemen,
(See link above) GM and the other big three are trying to “invent” a 100% electric car, but it can only go 40 miles on single charge. Why are they reinventing the wheel you guys already developed? Is there any “sharing” of gov. funding so your company can get alot of that when you either sell or lease your battery design? Or are you even interested in helping to develop an affordable vehicle that will go 100 miles or better on a single charge? I’d buy that right now, today, for double what cars go for now (40-60K ) to drive that for the next 30+ years…..I’m sure many,many Americans would go for that deal instead of getting “raped” by Oil companies and other nations now. Please reply and tell me what or if there is a plan. Thank you!
Hello,
My question is on batteries. Are you offering a replacement plan on the battery pack. I would be much more inclined to purchase if you offered me a 100,000 mile battery replacement plan that provided me with a new battery pack after my first 100,000 miles of use. I don’t want to have to worry about disposal, ever.
Thanks!
ROY: I quess I missed something. Why is Tesla spending millions testing 2 speed transmissions if an electric car doesn’t require one? And wouldn’t it be more efficient if the car was able to cruise at an engine rpm of say 3,000 instead of 8,000 or 9,000 rpm?
Looks great. But, any real attempt to get through to any of you about how to wind a better electric motor is all been in vein. Consider this, a transformer has a primary and a secondary. You only have to saturate 1/2 of the core to saturate both halves. The difference is simple, you have two opposing magnets in the same core. Unless, the magnetic circuit is complete, all that really happens is that you induce a current in one shorted coil on the same winding form, which opposes the winding that power was applied to. When you have to magnets opposing, that’s called a compound magnet, and it doesn’t matter if it’s AC or DC. Building a motor is dependent on an open magnetic circuit. So, by simply including a shorted winding behind the powered windings, the short drops your power demand for the core to saturate by almost half. Of course, this is either RPM dependent or Frequency dependent. At the point you are using a Squirrel Cage Motor, one extra set of shorted windings on the rotor could change power demand significantly. But, I don’t even know if you’ve visualized this correctly. On a cylinder, one end has a shorted winding, the other a powered winding. The shorted winding can be introduced into the core up to the neutral point of the AC powered magnet. The wound end would face the rotor, the shorted end of the cylinder would face away from the rotor. It also effectively pushes magnetic lines out of the core. Unless, you take some good transformer metal, and set up some permanent magnets to oppose with 3 layers of metal between them, you won’t see the real action that the permeable metals have. Permeable metals can act as guides for the magnetic lines, and the permanent magnets won’t loose power if you do your math right, and just act like powered DC windings..
There is another trick to winding or making a compound magnet, where it does have to well defined poles. If you take flat magnets that are north on the top and south on the bottom, they represent flat wide coils. Placing them side by side on a flat piece of metal where they all oppose is simply placing north on one piece of metal and south on the other. Since, magnetic line do not like to share the same spaces coming from two different sources, the magnetic field lines are forced out of the permeable metal that you stuck them to. It it a real pain but butt them up together end to end, and pinch them between another piece of permeable metal. Then the field will reach much farther in feet, than it ever did. Especially with 5 ceramic and up through to where you’ll need a vice, expoxy, and some screws to hold the thing together. Likewise, the rotor could apply allot more force to the rotor if there were 3 to 5 windings in parallel between two pieces of metal verses just one.
After reading most of the product spec’s and being a firm believer in the electric vehicle as a necessity in years to come I think you guys have a winner in the making. I’m working on the other end, electric propulsion as an auxiliary to sail power using a hydroelectric system to recharge while sailing. A sailing vessel is the perfect platform for me as I will be on water most of the time, when not it will be my electric bike…….hahaha how is the Nano Silicon wire battery stack up as a future of power storage, there was some hipe on it a short time ago and then nothing? Inganear
CM;
responding to your old June 12 post, “However, after over 44 years of research, plasma focus fusion still hasn’t reached breakeven, and every step closer to breakeven requires more powerful and more expensive higher voltage higher amperage power supplies”, you are not talking about pulsed fusion like FF uses. Any attempt to sustain plasma fields runs into the kind of escalating “cost” issue you describe. However, the FF approach is to ALLOW breakdown of the plasma, but to arrange that as it happens, so does a ‘little’ burst of fusion. Repeated about 330 times a second, that is enough to generate a significant power flow, as described. The power required for each “burst” is well within the range of top-of-the-market commercial capacitors, which are available now.
As for “no reactor”, various versions have been run with lower power fuel (Deuterium) to generate hard data on a number of aspects of the design, and fusion has been routinely obtained, but of the “messy” neutronic kind, that throws out lots of high-speed neutrons. That’s desirable in a heat-engine reactor, but is not where FF is going.
To “focus” on the core difference and technology, a tuned power level has been found that avoids the 25X higher X-ray cooling expected from using a fuel (boron) with 5 protons instead of one (as in hydrogen isotopes). It uses a particular quantum barrier that keeps most of the electrons in the plasma from impacting the ion shells. The payoff is that for the first time, “aneutronic” proton-boron fusion can be sustained for long enough to generate power. That’s only a few hundred nanoseconds at a crack, but the more times per second you do it, the more power you can get. For engineering reasons, it looks like 330Hz generating 5MW is the sweet spot.
The other key is that all the power is drained by direct conversion to electricity without thermal conversion steps. (No boiling water anywhere in the loop!)
Watch the Google Tech Talk video.
Hello,
I have commented on this before, but I loose my place so i don’t know if this has been responded to yet.
Have the R&D crew put any thought into the new 80% efficient Spray on Solar collectors yet?
I am thinking painting the Tesla with that would increase it’s range, and make it so you could recharge via parking in the sun while you work all day.
Roy, This is very fascinating information. I hope you guys make it to the forefront with your technology. I beleive the days of fossil fuels are coming to an end. I have been mulling over an idea for quite sometime and your company seems to have the innovative spirit and technology to put some serious thought to it. In general my idea is to develop a hybrid car that employs electricity and pnuematic piston engine technology. My idea would be similar to that of hybrid/gas cars; however, the piston engine would be powered by compressed air. Like regenerative braking, you could generate compressed air from the motion of the wheels or the engine. If this technology can be developed, couldn’t you offer a drivetrain to effectively replace most gas guzzlers on the road? I would love to hear your thoughts on this. Please feel free to contact me if you would like to discuss my idea further.
Best regards,
Randy Littlefield
Arlington, WA
The Tesla roadster is an interesting machine but still has a fundamental problem: How do you charge the battery without a charging station? Drivers shouldn’t have to worry about running out of gas - figuratively speaking - on trips away from home. The problem I see is that the battery pack must be sized to provide agility and speed in traffic, which compromises range.
In current hybrid cars, the engine is sized for cruise on the highway and additional energy for acceleration and hill-climbing comes from the batteries. Why not turn this around? Size the electrics for cruise on the highway and provide a small engine/generator unit for extra power in traffic and for charging the batteries. The car’s range would be limited by the amount of fuel required by the engine. If a charging station is available, the batteries could be deep-charged over night, which would reduce the demand on the engine/generator unit.
I own a Toyota Prius, which - for me - is a good car. But I view hybrids as an intermediate step between current mechanical-drive vehicles and something better in the future, be it pure electric or fuel cell. The limitation right now is infrastructure, which is set up to support gasoline-powered vehicles. People won’t invest in infrastructure until they see a clear direction the technology is headed.
Your roadster is a step in the right direction but, like automobiles a hundred years ago, it’s something only the wealthy can afford. When you get electrics down to the Model-T level, the buying public and the infrastructure will follow.
Use the rotary motion of the automobile, temporary and permanent magnets
installed on the wheels to induce current, (magnetically, not w/a generator),
and trickle charge the batterys.
Again, I suggest that the ‘range extension’ be done by providing a power cord which can plug into an ordinary electric socket and has an electric meter built in — so that you can go to anyone with an outdoor electric socket and say “I’ll pay you $X per kilowatt hour!” It would also make it easy for anyone to become a recharging station: just put up a price list and a sign pointing to the electric socket, and they’re done! Given that, it would become easy to establish a network of recharging stations scattered throughout the “hinterlands”, perhaps at superhighway exits; very few places are really off the grid.
I don’t know how much work the ‘metered power cord’ would be, but I would expect it would be relatively little, compared to the cost of building cars. This small technology investment, plus some time invested socially to get appropriately respectable shops to agree to be charging stations, would reap major benefits in terms of creating a recharging infrastructure.
In the early days stations would probably trust Tesla carowners not to fiddle their power cords; as time went on and Teslas were bought by less honest peopel, you might find yourself selling the cords to the stations rather than to the carowners. Still effective at creating the recharging network.
Virgil H. Soule–
A Ford Model-T cost $850 in 1909; inflation-adjusted (using the CPI), that’s about $19,387 in 2007 dollars. Considering a Toyota Prius base model costs about $20,000 (www.autobytel.com/content/research/detail/Toyota/Toyota-Prius.htm), it would appear that you are basically driving a Model-T equivalent right now (albeit a far superior vehicle)!
Model-Ts came down to about $300 after roughly 11 years of production (including inflation). Assuming similar learning curve effects (en.wikipedia.org/wiki/Learning_curve), innovations, and scale economies take hold of the proposed $60,000 Tesla Model-S when it arrives in 2010, one might expect a base model price of an all-electric Model-T (Tesla’s code name for this vehicle is Blue Star) to approach the price of a Prius by ~2020. If it should happen any sooner, as I suspect it might, it would be because modern engineering and management techniques speed up these effects.
In both the case of the Prius (now), and the Blue Star (future), what amazes me is how much further $1.00 (inflation-adjusted) takes a person today versus 100 years ago!
Nathanael,
What you suggest is already available within the car’s charging system. The actual charger is located in the car. It’s software can meter the Kw/hr used during a charging session. The cord you suggest already exists as well. The “mobile connector” listed on the 2009 Roadster spec sheet will allow for a connection to the standard (in the US) 220v clothes dryer outlet found in most garages and can be adapted for 110v as well (although, from a dead start it would be a long wait for a full charge at 110v/15amp). Hope that satisfies.
I do not know exactly where this question should go, but here it is. Have you thought of splitting the battery pack in two and placing one in the front to achieve a more 50 - 50 weight distribution?
Thank you ahead of time,
davidW
This guy doesn’t understand inductive loads. Take it from someone who designs motor controls for a living: The current from the battery can average way less than the average motor current with or without a transformer, especially at low motor RPM.
James William Elger: I’m not sure what you are trying to say, but since you mention permanent magnets and shorted windings it probably doesn’t apply. Tesla Motors is using a 3 phase induction motor that does not use any permanent magnets or brushes, and unlike single phase shaded pole motors doesn’t need shorted windings - adding shorted windings would actually make the motor less efficient. Tesla Motors has licensed technology from or hired the best and brightest electrical engineers in North America, they really do know what they are doing.
Brian H: I do understand the basics of focus fusion, that it is a intermittent pulsed process, and I even knew about the direct energy conversion to achieve higher efficiency. Yes, a large capacitor bank slowly charged up works fine for a single pulse, but successful power production requires a steady stream of frequent pulses - you mentioned 330 Hz. To create 330 pulses per second, each powerful enough to trigger the flux colllapse density and temperatures required for fusion does indeed take a high voltage very high current power supply. Thanks for proving my point. By all means, we should continue research on it as a scientific endeavor, but we shouldn’t bet on it solving our energy crisis, as there is a high possibility that it will prove to be too expensive to be practical.
Gian: The “spray on” solar collector is being developed, and is not yet on the market. Tesla Motors is going to wait until all the bugs are worked out, then see if it is cost effective when it goes on sale. Efficiency is about 8%, not 80%.
Virgil H. Soule: Charging the battery without a charging station is like refilling a gas tank without a gas station - except that just about any 110 or 220 volt AC outlet can serve as a “charging station” and they’re a lot more common than gas stations. Also, IC engines are at their peak efficiency only in a very narrow range of power and speed, but electric motors retain extraordinarily high efficiency over a very wide range of power and speed. For that reason, the best “plug-in hybrid” design is to start out running batteries only, then use the IC engine as a range extender at a steady “baseline cruising” power output, with the batteries providing extra power whenever needed.
rosleand67: Whenever moving magnets generate electric power, they also produce a “magnetic drag” that is proportional to the electric power produced. That is how “Regenerative Braking” works, and the Tesla Roadster will turn on regenerative braking when the car needs to slow down. Your scheme would cause magnetic drag and make the motor work harder, using more electric power than the magnets would produce, so the range would be less.
David,
These guys (Teslas Motors) are way beyond the design stage. All DOT/NTSB crash tests have been completed (ETXREMELY expensive process). What you suggest is neither needed or possible (at this point). One short test drive in the roadster and you’ll be convinced that it’s very well balanced.
I was wondering if Tesla is looking into solar powered air conditioning? I did see a couple of cars on the Web that were experimenting on the idea of using the Sun to cool the car and one company is using the idea of using solar to so you would come back to a cooled car! This would be a great idea for no one likes going from an air conditioned office to a very hot car! Also in the navigation package doe it have a subscription for traffic!
Thank you, I guess I forgot Tesla is not Detroit, and that you were working on next years model. I would love to test drive a Tesla, however even trading in my Saturn Sky (not a bad sports car for an IC) I am still way to short (cash that is). I love what you are doing and because of it, I know some day I will be driving a comparable EV sports car in my 30 K price range. So keep up the good work.
davidW
Randy Littlefield,
Good idea, but UPS beat you to it. They have a small number of delivery trucks using a hybrid gas - hydraulic system.
James M: I can’t speak for what Tesla is working on since I’m not an employee, but with their focus on production of Roadsters and designing the Model S, I doubt whether they are putting any effort on solar power for the air conditioner.
However, with regard to coming back to a cooled car, that is already in place, at least in some situations. Unlike an ICE car, the engine (in this case the motor) does not need to running for the AC to be working. I spoke to a Tesla rep at the Menlo Park store opening, and was told that you can leave the air conditioning on while you are having lunch, and come back after lunch to a cool car (the AC running off the battery while you were away). Not sure how much of the battery’s charge would be used, but I doubt it would take much. Also, I did NOT ask whether you could leave the car at 8am when you go into the office, and program the AC to come on say at 4:30, so it’s cool at 5pm when you are ready to leave for home. Does anyone know the answer to that question?
Dear Tesla: I’m a Silicon Valley engineer. I drove to your new store in Menlo Park. You need to take some of the motors, controllers,
batteries, etc that are laying around in engineers’ desks and show them off at the dealership. The minimalist-Zen thing is fine,
but not to the level you’ve gone to.
Keep up the excellent work!!
I have a question. why did you use a one ratio gearbox instead of a continuous variable ratio gearbox? beacase of range? efficiency?
once again excellent work!
Excellent idea. Some sort of timer for the car’s climate control - maybe with a remote override system via the key fob or possibly a cell phone in case you have to return to the car early / late. The car’s heater is 4kW, www.teslamotors.com/blog4/?p=43 but I think they recommend heating the seats as this uses lees energy than heating the cabin air. Not sure about the power of the AC.
It’s incredible!! I’m wating for that car. It’s expensive. What are you think about to get more range to drive the car? like self efficient, almost 80%?. No more connection like the cellphone every night.
I can confirm (following discusions with a Tesla sale rep today) that the car currently does NOT allow you to program the heater or AC to come on at a user-specified time. However, I believe the battery charging can be programmed in this way, so perhaps this functionality could be added at a later date.
My visit to the Menlo Park store last Saturday was great. I got to sit in the blue Tesla #16 out in the parking lot. What a car! I wish I could have seen it move and hear how quiet it was too. The store coordinator, Debra McCormick, was most knowledgeable and helpful.
Hey, I just wonder if theres any pictures of or sketches of the four door car?
Best Regards
Josef Angeria
I am living in Sri Lanka (Small Island in Indian Ocean –below India), I am so much passionate about BEV (Battery Electric Vehicles) and was doing small R&D and reading stuff (Internet). Once I read this page I was enlighten about the BEVs. Thank you so much for the wonderful articles and the images!
If I can, I will work for TESLA for free! Since I want to be part of the ‘car of the future’!
Keep on going… future belongs to you!
We used a hewland 5-speed with an adjustable clutch on the input coupled to a custom dc motor on the Brawner EX-12 electric race car built in the early 90’s. The motor/control were designed to maintain the commanded current while speed shifting. The motor was designed to run at full field up to 10,000 RPM with fully charged batteries and peak output was a little over 300HP and motor torque was usually limited to 160 fl-lbs via the max current command setting, so the clutch was set at around 300 ft-lbs, a value that exceeded motor torque but low enough to prevent damage to the gearbox. This limited shifting time to 20-50 milliseconds, depending on the throttle posiiton, which was slow enough that commanded current could be maintained during shifting. The same setup was installed in a truck and run over 70,000 miles over a period of several years.
I have been away from this blog for a few weeks, and I see that there are some unanswered questions aimed at me.
mroman: Tesla has decided to ditch the 2 speed transmission in favor of a single speed. This is taking full advantage of the electric motor’s flat torque from 0 to mid operating range, torque then falls off gradually. Aside from a little increased friction in the bearings and gears, there is no efficiency advantage at 3000 rpm vs 9000 rpm.
Randy Littlefield: I am not an employee of Tesla, just an avid fan who has spent an inordinate amount of time on this website for the last 1.5 years. I see a lot of repeat questions/suggestions and try to answer what I can. Your suggestion of recovering braking energy via compressing air has merit, and is being done by a European company. There are many possibilities including hydraulic, flywheel, even springs. But in general it is best to use a method that involves the least complexity. In Tesla’s case, since they already have an electric motor, it makes sense to use it for regenerative braking rather than add an addtional technology like pistons and pneumatics. I think there is more than one company pursueing compressed air power, here is an article on one, rawstory.com/news/2007/Air_car_runs_on_compressed_air_0104.html My personal opinion is that it will not be as good as batteries and electric motors.
Have you guys seen this video?
www.facebook.com/video/video.php?v=523517414743
It looks like the Roadster is only 1-wheel-drive. What gives?
The board should totally get in contact with aircraft manufacturers… My head would explode (in a good way) If I heard there was an all electric aircraft prototype to be made by Tesla Motors. I’m only a 17 yr old kid from Western Australia, I therefore lack the relevant degrees in physics, aeronautics, and engineering; so, can anyone explain to me why this isn’t possible when the Roadstar’s engine is 115lb with 248 max hp, while a continental O-200 engine (powers a range of light Cessna aircraft) has a dry weight of 170lb and around 100hp! Sure, take the fuel/battery weights into account and the Tesla totals at most 1115lb (or roughly 561 kg). Apply this to the Cessna 152; the max takeoff payload including passenger in roughly 570lb. Take off fuel tanks, free up say 500lb, fit in the Tesla pack; with the old powersource the payload would be able to take off (even if its barely). With the Telsa pack retro fitted, hopefully the max take-off weight will have increased and: TA DA! There (potentially) you have it. A reliable, traditional, reasonably priced small electric aircraft.
This could be done within a relatively short period of time. This is also, ignoring the new ultralight glider-style designs that aircraft companies are making for fuel-efficiency! Get someone to bring this up at a board meeting and then (pretty please) email me! I would like to hear exactly why this can’t be done (hell, if lacking staff, donate an engine and powerpack to the ‘mythbusters’, they’ll come up with something good… before they blow it up for fun)… or I would love to hear a trial date, and a link to the you-tube footage!
Cheers- keep up the visionary design philosophy
Larry: Nice clip. Only one wheel will spin on most cars with a standard differential. The Tesla does not have positrack.
Stuart McDonald: You might be interested in this, www.aeroconversions.com/e-flight
Nothing to comment to current blog, but I had some weird experience today.
Here I was walking to get something to eat and saw logo on one small silver-colored sportscar. TESLA ROADSTER my brain said to me. Then when my vision cleared I noticed that this isn’t Tesla, it just had similar logo. It appeard to be Hyundai Tuscani with Tuscani logo in front and in back of the car. Much less cool than Roadster.
Then an worrying thought appeared in my mind. If I can’t tell car from its shape what it is before I’m next to it then it will never be major car. I can distinguish BMW, Mercedes, Saab, Peugeot most Audi and of course most Ferraris, Lamborghinis, Corvettes and Porsches by a quick glance. Tesla should have something of its own in the design, not only the logo. Something unique. Something that you notice immediately.
Sure Tesla Roadster is great looking car, but seriously if you forget that you know that it is EV and forget about that you know who makes it could you notice it between similar looking sportcars like Elise and Exige? Could you tell immediately that it is not YetAnotherLotus or something? I bet you would just walk by and wonder a few seconds about “nice looking unknown roadster” and then forget about it completely. Roadster shape is not something that makes you turn head when you see it first time around. It could turn your head if you see and (not) hear it moving, but that is another thing completely.
I hope new design director can put something unique to Whitestar design.
I read the Tesla update and the entire blog and found the range of topic interesting. Here are some of my thoughts on the subject.
First I am excited about the possibility that somebody may finally get an electric car on the road. I congratulate the Tesla team on their ingenuity and efforts to improve and only dream that I had the economic recourses or talent to be a part of a project like that. In the blog, I am surprised that no one mentioned the electric car that GM had available in 1996. 12 years ago they had 800 electric cars on the road that they leased to people. But it was not profitable for them, so they scrapped the cars, literally. Terminated the leases, collected them all back and scrapped them to get rid of the evidence that it was possible.
The cars did not require servicing which is a big profit center for the company and dealers. And the battery that got them 60 miles per charge 12 years ago, the company that had the patent was bought by Exxon and the battery was never heard from again. Don’t count on the Big 3 or oil companies to do any thing for us that isn’t going to require us to give them a lot of our money for the stockholder. I suggest that anybody that wants more info of this subject to visit WhoKilledTheElectricCar.com and buy the documentary DVD for $10. It’s a real eye opener. There is even a Tesla in the DVD.
What I’m hoping for out of this electric car push is that some one will put together a conversion kit where myself or a chain of “retrofit garages” can take and old Chevy Vega or BMW Z Series and take out engine, transmission, alternator, AC, radiator, and exhaust and put it an electric motor, modular expandable battery system, and energy managements system, and universal joint adapter, a gas pedal to power pedal adapter, electric power brake assist system, power steering assist system, heater, battery charge level indicator, and a cord to plug into a 110 receptacle (to connect to my solar grid tie system). I don’t need a more than an 80 mile range and certainly don’t need to do 60mph in 3.9 seconds or a vehicle that does over 75mph.
The modular expandable battery system would be modular so there would be flexibility so modules could be positioned as needed or convenient in the vehicle and expandable to add range as budget and need required. I currently spend about $3,500 a year on fuel and maintenance with my current air polluter. And then there is the subject of the wear and tear depreciation difference between say 60,000 miles on an electric motor as compared to an internal combustion engine. Just go back to the retrofit garage for a new body style.
In the meantime I am cheering for the Tesla team as the ground breaker. - and thanks for the updates Tesla.
Does the Tesla car include a functioning OBDII connector?
Thanks,
Jim Dunn
I’ve looked all over the Telsa website but haven’t found where there’s information on the power required to charge the batteries. Since I buy electricity by KWh, if you could post what KWh are required to produce a full charge from “empty” to “full,” that would be useful.
Thanks!
AlBee: About 60kWh. Battery has capacity of 53kWh and with losses you need to charge about 60kWh. With that amount you drive about 160-260miles (depending of your driving style and location).
Just a question,
Is Tracy Smith one of the designers? Which office is he located? I talked with his mom Bev a year ago before going on a year long trip, leaving Sydney Saturday, 16 for L.A. Just wanted to say hello! I was her neighbor across the street on 14th in Portland.
Thank you,
Bruce Bollard
AJBee: The battery pack is about 50kWh, charger > 90% efficient, therefore about 55kWh for a full charge. Tesla’s home charger draws 70 amps at 220 volts, which requires at least a 90-amp breaker (code requires the EV to draw no more than 80% of the circuit rated load.) Takes about 3.5 hours for an empty to full charge.
Albee;
The ESS holds about 58KWh, and there is some loss while charging, so almost 70KWh must be fed in, if I recall correctly.
Just wondering for any and all who can comment…Is there any logic to covering the roof and rear deck with solar panels? I have no idea of the electric math but it would seem that sitting all day in a sunny parking lot should help to recharge the battery somewhat.
Any update on update? There has been some prototypes running 1.5 drivetrain. Any change in acceleration? 0-60 and 40-75 (passing acceleration, which is way more important than getting to 60)? How about range? Top speed? You did give some estimates, but real-life numbers would be nice to see.
Congratulations to JB Straubel!
See the interview (where he also mentions som ongoing work about better motor and batterypack to get a better efficiency and range) at:
www.technologyreview.com/video/index.aspx?id=742&brightcove=1655720422&iframe=tr35&autoplay=true
PS: One detail - watch the display in the video (at 4:00 min), there can you read “74.31 kWh Net Energy”! Does this mean it takes 74 kWh to load a 58 kWh-battery? Or is this an enhanced prototypebattery which has higher capacity and will maybe be available soon? Higher range would be cool!!!
CM’s response to my earlier comment is about what I was talking about, i.e., use an IC engine/generator as a range extender for a basically-electric car. My brother, Irvin, had a ‘26 Model T while we were in high school that got about 200 miles to a tank of gas. That wasn’t a problem as long as gas stations could be found along the way to where we were going. If you have to stop for an hour or two every 250 miles, it’s going to be tough to do 500 miles per day.
JB - Congratulations on a terrific honor for your innovative work in this field. Keep up the good work!
Arrakeen, I bet that 74kWh is caused be regenerative breaking. I think that counter does not reduce when you gain energy from regenerative breaking, so you end up using more than your battery pack has.
I hope the next blog talks about the new battery pack hinted at by Elon. There are so many possibilities including this one panasonic.co.jp/corp/news/official.data/data.dir/en061218-2/en061218-2.html which would give 25% more range, but at what cost? This option would be a drop-in replacement for existing cells and may not ever require re-certification. As a premium battery the cost would be high but if Tesla struck a deal for a high enough quantity …
Timo;
The influence of regen braking will vary depending on where you are driving. Very little braking is done on long-distance highway driving, while city driving has frequent slow-fast cycles. And regen doesn’t give you more energy, it just makes the use of it more efficient over the length of the particular distance travelled.
Nice job overall. Very pleased to see the transition from a 2-speed to single speed. Takes a little more stout IGBT system but its well worth the effort to focus on the controller (and motor in some cases) rather then add gears.
I have a few questions regarding the drive system. Hopefully they aren’t infringing on any guarded technologies.
Gearbox
I noticed helical gears which are quiet but not as efficient (or inexpensive) as straight cut spurs. Presuming this is for noise emission.
Have you included accoustic measurment in your durability testing?
Given the high RPM of the rotor is the first reduction gear given a forced oil spray?
Traction Motor
How many Poles?
Whats the rotor peripheral velocity at 14,000 RPM?
Do the rotor bars require any sort of girdle?
Are both bearings insulated or just one end?
Is the coupling insulated to avoid any galvanic current to the gearbox?
What kind of lubricant is used on the bearings?
Has there been any environmental testing for rotor journal erosion under the bearing?
Whats the design life of the bearings with the current PEM configuration?
PEM
Liquid or air cooled?
Square wave or stepped index?
How low of motor RPM does the regen/retard mode operate?
Brian H;
I know. I’m just guessing that this 74kWh which is visible in video Arrakeen posted is caused by meter “lying” about how much energy is being used. It shows how much energy has been used, and in order to show that right it should decrease whenever regen braking is used. I bet it doesn’t. OR they are testing improved ESS. Which would be cool. 74kWh vs 53 kWh would be about 30% increase in battery capacity giving Roadster 280-290 mile range. I hope. That is still too little, but it is getting close.
I’d say that you have optimal range when you can drive 10 hours at 60mph average which single charge. IOW Range should be 600 miles. Silicon nanowire batteries would make it possible while still being only about 30% of size of current ESS. We need only triple capacity to achieve that goal. It won’t take long. In fact it might be reality in next year already. That would make Whitestar quite interesting car. Triple the range or cut ESS price to one third, there’s the question.
Are any car rental companies seeking to buy Teslas for renting out to curious unrich people such as myself who are dying to press that Tesla accelerator to the floor and feel what happens? I have sat in one but desire to go all the way and drive one by some hook or crook like renting one.
Timo;
there’s new cathode stuff out, too, including viruses growing nano-nodes, BION. That could enable the full 10X benefit of nanowire batteries to be realized. In that case, you could have both 3X the range and 30% the weight!
Oops, I meant new anode results. The ‘07 Stanford work was with nanowire cathodes.
Brian H;
Any links to research? That’s interesting. I’m also wondering if magnetic resonance induction could be used to fast charge large battery safely without losing too much in process. That MIT research team and Intel using their technique have got 75% ratio for several meters away. I’m wondering how good it could be with only centimeter or two apart. Charging 150+kWh in only few minutes would require enormous voltages and amps and making that safe is something of a challenge if we want really fast charging to be possible for mundane people. Fast charging would require battery to battery tech, no-one would like to have that kind of connection to grid in their homes (or hotel/motel/restaurant).
Timo, Brian H,
How do users of heavy duty industrial equipment connect to the grid, and how do utilities maintain the quality when these users switch on and off? Always been curious about it but I have never researched it.
I have read about the use of a capacitor in lieu of the battery. Is there any leaning towards that type of technology? It would make for a lighter, more powerful, more responsive charging reservoir of energy for the vehicle. Thanks, Rich
John Denman: I doubt that you will get such specific information about their design. Tesla has a general discussion on motors here www.teslamotors.com/blog4/?p=45 The motor cannot have a large number of poles since it is designed to run at high rpm, therefore I am sure it must be 3 phase 4 pole design. It weighs 115 pounds. They have a patent describing the rotor in some detail which has wedge shaped bars to insure snug electrical contact with the ring at the end of the squirrel cage. Although I don’t know how, I am sure the Tesla engineers have addressed gavalnic concerns, as that is common in the industry of high power electric motors. Would you explain to me what stepped index is?
John: I forgot to add there is a blog about the PEM here www.teslamotors.com/blog4/?p=63 I think they use a Texas Instruments TMS320 series DSP, models at and above TMS320LF2810 run at 150MHz. They produce PWM output.
Hi,
I probably have missed the discussion, and something oh so obvious, but why can we not have electric pusher trailers that suddenly double every vehicles gas mileage while we work out the much longer term problems of turning the world on to EV? More people have a tow hook than currently dream of EV. Simple maths says I save £500 a year if my mpg doubles. If a pusher trailer costs not much more than twice or three times this (and I’m talking produced in 100 X millions) who wouldn’t? I hate parking in town anyway, but I want my mpg doubled.
cheers
Russell
Jeff;
I don’t know. I have some idea about those but never researched it either. Some really heavy duty things use flywheels for killing the spikes.
Richard C;
Capacitors would not be lighter. Capacitors in general have poor energy density but they do have good power density.
There is a company called EEStor that have some pretty extraordinary claims, but that might be waporware.
en.wikipedia.org/wiki/EEstor
If, and I emphasize that if, it is true EEStor would be very good news for EV industry. It would *still* lose to silicon nanowire batteries in energy density, but if those claims are true those would be cheap compared to lithium ion batteries, and they would suffer virtually no degradation from recharge cycling.
Capacitors have severe limitations for long-term storage, and are VERY dangerous if any kind of short is possible. Think high-temp vaporized metal expanding at Mach5.
Capacitor-buffered battery packs have interesting possibilities. though. EEStor claims to have solved the storage problem, but the described tech depends on unheard-of precision in producing insulating layers. We’ll see.
Actually, I had it right the first time. Stanford was researching anodes, and the new research is for cathodes. Duh.
As far as the Stanford nanowire research goes, the link has been up a few times: Nanowire
The cathode work is in a couple of venues: here and here.
JB - Congratulations on a terrific honor for your innovative work in this field. Keep up the good work!
Hey there. I see that everything you have done so far with the tesla roadster is great, but is there any way to make the regenitive braking more effective/efficient? Also i have heard about this new technology using nanowires in a block of silicon to increase the energy density by 10 times that of a conventional lithium ion battery as claimed by the site i was reading: news-service.stanford.edu/news/2008/january9/nanowire-010908.html I was wondering if you had heard of this technology and if you were ever think to put it into you cars due to the fact that the only let down to the roadster is the range and of course boot space.
Also i wondering when the roadster was going to be built in RHD and when it was going to be released to the NEW ZEALAND market. I’m sure there are many keen customers in my conutry because we love being clean and green and also due to the fact that us Kiwis have a love affair with our cars.
Regards, Nicholas Hill
How long after release of vehicle, will drivetrains and electronics be available for separate purchase?:) And have you thought of using a electrically driven planetary CVT setup? Keep the main drive and its peak performance Rpm and manipulate the gear ratio to take advantage of mechanical advantage in both directions?
Nicholas:
I’m sure Tesla has heard of every emerging battery technology in development, and probably more than a few under NDA that haven’t seen a press release yet. Just knowing about research doesn’t help any unless there is also a proven manufacturing process, and the ability to turn out huge quantities of the things. Getting 10x the energy density is nice, but not if it costs 50x more. even 12x more it might not be worth it.
When a battery comes out that’s more energy dense, lighter, cheaper, longer lasting, and is produced in high volume… you can be sure Tesla will be making a battery out of those cells.
Jeff:
Wouldn’t a planetary gear have the same (or greater) durability issues with extremely high torque at 0 RPM as the previously failed two speed transmission? I know that belts of belt driven CVTs get shredded almost immediately when trying to cope with the forces electric motors generate.
A better solution to transmissions would probably be in-wheel hub motors, or dual-motors mated directly to the drives haft or differential. With two motors you can run them in series to get the torque needed to get moving, and switch to parallel to get the RPMs needed for high top speed.
see: www.evalbum.com/035.html
Absolutely wonderful…
Anyone involved in this jewel of a production should and MUST consider themselves fortunate.
I too have a passion for mechanical design, engineering and speed combined
with a strong environmental consciousness.
If I had to do it again… I’d be where you are now, if only I was in the right place at the right time.
Enjoy the ride.
PS
Don’t forget the Lightning…
i cant wait until they release the model T’s!
-jake @ Live Wire
Here is how the range of an electric car can be extended.
The motor and the electronics are not 100% efficient. There is energy lost in the from of heat. That energy can be captured by devices using the Peltier effect to generate power, and that power can be used to extend the range. Also, tires generate heat from friction. Peltier devices could be used to convert that heat into electricity to extend the range. Also, the surface of the car becomes heated because of aerodynamic drag, much like a meteor, although obviously not to that degree (fortunately). That heat could also be used to generate power.
Combining all these sources of lost heat energy could surely be used to extend the range by at least 5%, and the cost of doing so probaby would not increase the price of the car by more than $20,000. Do the math and pay back would probably take less than 50 years. Thus, if the car is very durable, and you keep it for at least 50 years, and the intererst rate is less than about 0.001%, it would be a worth while investment. The car would make a good college graduation gift. It would pay back shortly after retirement.
Surely this would work better than having a wind turbine charge the battery while driving.
man you guys are rockin my world…how bout a flying tesla.. electro-jet turbine vectored thrust nozzles instead of wheels..it sits on a cussion of air ..start it up and it automaticly throttles up and hovers three feet off the ground…step in and fly !
Tim, silicon nanowire or at least nanostructures are already in use in electronics. So I believe it would be rather fast transition from prototype to manufacturing. Basic manufacturing process (if I did read few texts right) would also be quite cheap. Also silicon is very abundant in the world (I believe it is something like fourth most common element in the world) which would make it quite cheap raw material. Lithium is still expensive and somewhat rare.
It could be worthwhile for Tesla to research manufacturing process as a combined effort with inventor and make their own battery factory once technology is proven to work instead of waiting for someone else produce those and then buy them.
About engines I believe simple one motor solution for traditional family car is the best. Hub-motors weaken car cornering performance, adds unnecessary complexity to electronics trying to simulate differentials and add additional very dangerous breaking points (and are also not legal if not used with traditional friction brakes). Two engines series/parallel would not give you much more than single does (single motor gives Roadster 125mph top speed and less than four second acceleration to 60. You really don’t need more than that.). KISS -approach is usually the best.
Now if you are trying to create all-terrain multiwheel drive vehicle like some military personnel carriers or some slow moving tractors then hub-motors would be good for them. It could even be worth in heavy trucks (..lorries.. whatever) to use hub motors instead of shaft-driven single motor. Added unsprung weight doesn’t matter that much if you are talking about very slow or very heavy vehicles. It also makes designing quite a bit easier if you can forget about engine and shaft spaces and it gives you some possibilities that traditional approach can’t give (like much better ground clearance and wheel turning when needed without shafts limiting your movements).
Rob wrote on June 20th, 2008 at 4:20 pm:
“Is Tesla Motors, Inc. going to manufacture a sedan version, semi truck version, pick up truck version, mini van version, and a motorcycle version of electric power transportation?”
I want a motorcycle version!!
If Tesla doesn’t want to make a motorcycle version, perhaps they could make the electric drive components and sell them to motorcycle manufacturers or to people who would like to convert motorcycles to battery-operated electric.
Mark wrote on July 11th, 2008 at 3:56 pm:
“To allow Powertrain 1.5 to propel the Roadster over the “magic” 200km/h, perhaps the actual motor rpm limit will be raised by 2% to 14300 rpm”
Some motorcycle engines run that fast, and they have a crankshaft, connecting rods, pistons, rings, valves, etc. If something as complicated as a 4-stroke engine can run that fast, surely an electric motor could be made to exceed twice that speed, i.e., > 28,000 rpm. That would make the motor smaller and lighter for the same power.
I read someplace that a company made a jet engine starter; the motor is connected directly to the compressor turbine and can exceed 60,000 rpm. It’s a VSR motor. The fact that the rotor is nothing more than a laminated chunk of iron makes such a high speed possible. If the rotor had magnets or windings, it could never spin that fast without coming apart. It may be that eventually, VSR motors will be used for electric cars. They are light, simple, and very efficient, the only problem being that the electronics necessary to make them work well are not easy to design.
Andrew wrote on July 14th, 2008 at 10:16 am:
“I noticed the TE curve published for the motors system has a linear drop in torque instead of a 1/x drop past base speed. This leads to a roll off of power.
Are you working on field weakening methods to keep a more constant power past base speed?”
Increasing the speed by weakening the fields can be used only for brush-type DC motors, and Tesla is not using DC motors. If my information is correct, they are using 3-phase induction motors. With a variable frequency and voltage inverter, the torque curve of an induction motor should look very much like the torque curve of a DC motor which uses field weakening to continue increasing the speed once armature voltage reaches the maximum.
I have had considerable experience with DC motors and generators up to about 50 HP, but all that experience is now obsolete. Almost everything I’ve ever done is obsolete. I hope that that doesn’t make me obsolete!!
Tim;
you are sure Tesla doesn’t need advice about batteries, yet you bring up the old dawg of in-hub motors! 4X the moving parts, and massive increase in unsprung weight, etc., etc. Fuggedaboudit.
Mileage: Your results may vary, BUT –
244 mi/charge. ~60 kwh/charge. 244/60 = ~4.1 mi./kwh. My local cost / kwh = 6.8¢. So 6.8¢/4.1 mi., = ~1.67 ¢/mi. Assuming $4.00/gal gasoline, that’s 240 miles to the gallon equivalent.
Suzuki SV 650;
About SVR motors. I got interested about that tech after reading your post. It appears to be very difficult to make car engine from SVR motor (all kinds of nasty difficulties like acoustic noise), but if it were possible then high RPM would be solved. I just read about passive sensory system that can sense rotor position up to 100kRPM speeds. And some small engines that can reach that speed.
How about ~400Nm EV which engine can reach 0-100 000 RPM without losing much torque in entire RPM range? Top speed somewhere over 200MPH and acceleration from 0-200 20s? Sounds too good. But then that would not be Tesla invention anymore…
A “Variable Speed Reluctance” motor (I assume that’s the “VSR” that Suzuki SV650 referred to) is simple and could have extremely high rotational speed, but it does have a serious drawback for EV use - it cannot perform regenerative braking!
Why not eliminate the 1 speed transmission and connect the motor directly to an 8 to 1 geared differential? Is there some limitation on differential gears?
I look at your new gearbox and notice that you are using helical cut gearing in the gearbox. I have an idea…On a conventional car the use of helical gearing quietens the gearbox noise but decreases the efficiency as some of the transmission loss goes into thrust bearings and not directly into the driven gear wheel. Racing cars and rally cars use straight cut gears! On an electric car we are often being told that they are too quiet!!! Why not use straight cut gearing in the gearbox and then the efficiency will go up (very important in an electric car where every ounce of efficiency adds to increased range) and the gearbox noise will enable pedestrians to hear the car coming!
I am very interested in your innovations and pleased that someone out there is starting to revolutionize the car industry,We cannot keep on burning oil like the is an everlasting supply of it.We need to save it for the more important uses and for future generations.
All the very best in your venture. When are we likely to get a picture of this new 5-seat sedan?
Regards,
Mark Howarth
I posted this question in another blog, but realized I should have asked it here. Has anyone thought of using this powertrain in an aircraft? Obviously it would have to be a propeller driven aircraft, but with so few moving parts, it would be as reliable as a jet engine. That’s assuming all the bugs are worked out.
To Mark - at high gear speeds (like in the Tesla’s gearbox), a spur cut motor pinion (and its mating gear) would be less efficient, heat up, and overload the bearings if it were straight cut. This is because any excess oil in the gap between gear teeth must get pumped sideways very quickly when its mating tooth engages, otherwise it will create a kind of hydraulic lock, with spur cut gears. At lower speeds (ie a normal Combustion engine) this effect won’t be present.
@Suzuki SV 650 regarding thermoelectric heat recovery systems: Generally, thermoelectric heat recovery systems are not efficient enough to warrant their added expense and weight. www.bsst.com has published several technical papers and conducted product development work to improve thermoelectric efficiencies to make them economically viable.
Glad to see a certain number (30 so far I’m guessing) of Tesla’s have finally been produced. The pictures are great, showing a double-reduction transmission. Since 8:1 reduction is within the range of a single set of helical gears, I wonder why a single reduction design wasn’t considered to improve efficiency a few percentage points.
There still seems to be a lot of comments regarding battery charging efficiency. The numbers I’ve heard on here over the past 12 months or so (75 Kw from powerline to get 63 Kw storage at full charge) - 84% efficiency, seem pretty reasonable to me. I would assume the efficiency would get several % points better if the batteries were trickle charged over 15 hours or so (mainly by decreasing the need to air condition the battery pack).
Isn’t it possible to make the roadster work like “Pepito Mobile”? Like once you start the machine, the machine becomes some kind of energy generator? Not only to spend the energy but to produce and save it …
I was very impressed with the powertrain update. How do I contact JB Straubel?
when will you built a two motor tesla without a differential and why not a 4×4 (wheels x motors) for the ulrimate handling?
Hey JB & friends,
Does anyone know about who maufactures 1 speed transmissions? I’ve found them through AC automotive, and it looks like maybe Brusa and Zebra, but they don’t seem very responsive to my inquiries.
josephebonaparte@yahoo.com
Hi,
I am also wondering why don’t you build two-motor car without a differential, if 4×4 with four motors would change the design too much. Wouldn’t be the two-motor car without a differential a more efficient solution with better driving characteristics?
I would like to know why it is so difficult to make a regular 5 or 6 speed manual transmission work with Tesla’s electric engine?? Is it because of the high rpms, the constant torque or maybe clutch problems?
Please respond.
Congratulations, great improvements. Your motor is a masterpiece.
Would it be possible to publish the S1 and S3 characteristics of your motor?
It would be great to compare your motor with other Servo-Motors.
Keep going.
Frank
@ CM
Intuitively, one would assume that a VSR motor (variable switched reluctance) could not be used for regenerative braking. Actually, VSR motors CAN be used for regenerative braking, just as induction motors can be used for regenerative braking. Please don’t ask me how since my competence in this area is limited. However, there may be engineers with post doctorate degrees here who can explain it.
I understand that VSR motors have acoustic problems resulting in a loud whine that could be beyond annoying. However, since the noise would occur at a rather high frequency, I’d think that it could be adequately suppressed by standard noise control techniques. Since VSR motors are capable of much higher speeds than the motors currently used by Tesla, I’d think that they could be much smaller and lighter for the power. Perhaps eventually they will be practical for electric and hybrid cars.
Regarding using helical gears, I understand the explanation of why spur gears would be inefficient at the high speeds at which the motor runs. But couldn’t herring bone gears be used to eliminate thrust loads on the bearings?
Will Tesla be making an electric motorcycle for me? Riding a motorcycle is so much more fun than driving a cage!
Congratulations, great improvements. Your motor is a masterpiece.
Would it be possible to publish the S1 and S3 characteristics of your motor?
It would be great to compare your motor with other Servo-Motors.
Keep going.
I have an idea about a transmission that can keep the same 0-60 specs and top speed, but offer improved range. Have the computer control the transmission, keeping it in the standard drive gear that’s already in the car, but have a second gear at a ratio that is set up for cruising. Only have the second gear engage after the cruise control has been enabled for about 2 minutes, where the computer will then shift into the second gear to improve the range. If this is set up correctly, your miles per charge will go up because the motor will spin slower. The motor has enough torque to push the car up a hill without shifting down, but could do so if needed. And whenever the cruise is disabled for 10 seconds or more and the accelerator pedal is released, the car will keep the regenerative brakes off until it shift downs, and will ramp up the regen after downshifting. If the driver would shut the cruise off but keep his/her foot on the accelerator, the car will stay in second gear until the pedal is released or if more power is needed at the wheels.
We Live in the mountains near Lake Arrowhead Ca.
WE drive a Lexus 400h
It does ok, lots of power, about 25 mpg we like the tech.
look, the country needs options regardless the politics.
stay the course.
dvd
What is the observed MTBF for the electric motors?
If one motor fails, can the vehicle still be operated? If so, does the PEM automatically reconfigure the drive train and what operational limitations are then imposed?
Thanks for the very useful information