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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.