Two real world questions: You made it from Tahoe downhill to San Carlos; is the trip in the other direction possible at normal speeds? It’s only about 200 miles to Yosemite; will the Roadster make it that far in the uphill direction? And a more theoretical one: how is is possible to go 245 miles at 31 kWh/100 miles with a battery that holds only 56 kWh? A LOT of regen?

—

Andrew’s response: The Recharge Energy of 31kWh/100mi is the electricity you pay for from the grid to recharge your Roadster.  It works out to ~75kWh of alternating current (AC) for a full recharge.  Our ESS (battery) produces direct current (DC) and holds ~53kWh.  The difference between these two numbers is due to charging inefficiencies, including the use of air-conditioning to thermally-manage the battery during charging.

Unfortunately, the Roadster cannot drive from San Carlos to Lake Tahoe nor Yosemite on a single charge at normal highway speeds due to the energy required to ascend the 7000ft+ hill climb (it may be possible at lower speeds, which significantly lower aerodynamic losses).  These trips, however, are still possible using our mobile charging kit or charging stations installed at partnering locations such as Hyatt Hotels.

Do you think that you’ve finally pinned the range number down or is it still up in the air?

—

Editor’s response: Yes, our testing was monitored by the California Air Resources Board (CARB), and we are in the final steps of certifying our numbers with them.

Great news on the range - congrats.

I have a couple questions on the range. A range of 245 miles at a recharge energy of 31 kWh/100mi seems to work out to 76 kWh of storage. And I suspect the batteries go down to a SOC of maybe 20%. So it seems the battery pack must be up around 95 kWh? And weigh closer to 2,000 lb.

Also, at 31 kWh/100mi, that works out to 3.2 miles per kWh, which seems lower than originally estimated.

—

Editor’s note: Your numbers are off. I would recommend taking a look at our battery white paper and our battery blog.

Andrew:

*** EXCELLENT INFO *** Thanks. Two questions.

1] On the Aug 29 tour SanFrancisco-Sacramento-LakeTahoe, with temps in the low 100’s in the Sacramento Valley, and your late afternoon drive from Sacramento to Lake Tahoe (estimated 121 miles), what was the calculated range ? (With A/C running continuously, I assume, what were other conditions: open top or hardtop ?, passenger ?, heavy traffic ?).

2] What effect on the Cd does the open top have ? What are the official Cd numbers and are they CAD models or wind-tunnel verified ?

Thanks.

165 miles worst-case is impressive

This post got me very excited. It shows that any obstacle is surmountable when addressed with passion, diligence and intellect. My brother in-law works in silicon valley, and the performance culture in that community is beyond compare.
I am currently beginning a feasibility study for a 300-500kW run of the river hydro project in southern British Columbia, having already completed contruction of a 90kW plant. Three years from now when it is completed (hopefully) I will have the financial means to buy a Tesla Roadster. I sincerely hope they will be available for sale in Canada at that point.
One of the other by-products of my line of work is that I have direct access to a 500amp line at up to 480vAC at my house where my hydro plant leads meet the grid - any chance of offering a made-to-measure charging system? (Think 40kW/h of charge in 10 minutes)
As I said, I sincerely hope you are selling in Canada at that point - I will trade in my supercharged Jaguar the second I see “www.teslamotors.ca”
Regards,
Chris

Great car, great concept. I read an article about a possible new power source for your vehicle, “ultracapacitor”. 90% energy efficiency, nearly instantaneous recharge, never replace, unaffected by cold, high current. Only question: is the energy density and volume enough to compete with your current battery. Please read NASA tech Tip www.techbriefs.com/content/view/2086/34/.
Please route this to your battery engineers.

—

Editor’s note: Have you read our blog, Balance? 

If you need someone to test the car in snowy winter conditions, drop me a line ; )

Great to hear the mileage numbers are better than expected. Certainly an unusual phenomenon in the automotive business. it’s also amazing that you disclose the “real-world” driving numbers instead of just the more attractive bench-test ones. It would be interesting if other manufacturers would do that same.

Fabulous. The buzz when this finally hits the streets is going to be unbelievable. Hope you are looking at accelerated ramp-up scenarios. Once you deliver 600 cars you may have demand for 6000. Or 60,000.

First of all: *GREAT* news. Range is back to 250ish and acceleration is still incredible 0-60 in less than 4 seconds.

This part of your text made me wonder:

## Even though we have confirmed the Roadster’s top speed capabilities,
## driving at sustained 130 mph speeds does subject our drive motor to
## extreme mechanical and thermal stresses. We have therefore decided to
## electronically limit the production Roadster’s top speed to 125 mph in order
## to maintain long-term reliability in the powertrain.

“motor to extreme mechanical and thermal stresses” means (if I understood that right) that limitation comes from engine overheating by high RPM and not from wind/rolling resistance. Which in turn could mean that it could go faster with third gear. Maybe you should add third gear? Or change gear ratios a teeny weeny bit higher speeds for second gear so that this strain to engine would not be that bad.

Not that I ever need over 125miles/h (200km/h) speeds…

BTW what in practice means “highway cruising”? What are the usual speed limits in US highways? Here in Finland usual speed limit is about 100-120km/h which is 62.5-75 mil/h. I’m trying to calculate what that would mean for me if I ever buy one of those Roadsters (or Whitestars). And I will, if it ever comes available in Europe.

From the “hindsight is 20/20″ department… The usual project rules should have been applied: “under-promise and over-deliver”.
It is great that you have gotten so close to the original estimates, but it would had been preferable if marketing hadn’t run with the original optimistic projections.

more than 250mi range down to 245 (under by ~2%)
135mph top speed down to 125 (under by ~7%)
13500 redline changed to 13000 (under by ~4%)
1 cent per mile changed to (less than) 2 cents per mile.
approx 2500 pounds changed to over 2600
delivery by changed to first quarter 2008 instead of October, 2007

The internet is still filled with the old specs, for instance:
www.supercars.net/cars/3528.html
www.automobilemag.com/features/news/0611_tesla_roadster/index1.html
www.seriouswheels.com/cars/top-2007-Tesla-Roadster.htm
www.newcars.org/cars/tesla/2007-roadster-convertible.asp

At least it is still 100% electric, and 0-60 staying under 4 secs is a real win!

I am still thrilled with the specs, and I am sorry that your team had to go through the “mea culpa” phase.
Oh, and I was sorry to see the price go up. Those who had faith to put down a deposit early at least got a good deal on that one.

Why is recharge energy 310 Wh/mile? I thought the car only needed 200 Wh/mile and charging efficiency was better than 90%. What on earth is going on, here?

—

Andrew says: See my response to Bill Arnett regarding AC recharge energy vs DC stored energy in the ESS. Bill correctly notes we’re achieving ~70% net charging efficiency. This results from the combined efficiency of the inverter/rectifier electronics and battery during charging, plus parasitic loads such as standby electronics and battery cooling (which consume power during charge that would otherwise go into the battery). Our number one design consideration was to maintain battery health, rather than maximize net charging efficiency. Even so, at 310 AC Wh/mi, our Roadster is still one of the most efficient EVs ever produced. For comparison data, click here. I also recommend our blog, A Bit About Batteries.

It’s interesting that the NYT techlology reporter David Pogue did a creditable job on EVs and the Tesla Roadster for CBS (via link on Tesla website front page), but Lawrence Ulrich, writing in the NYT itself (via another link on Tesla’s front page) let pass without question or criticism several vendor claims that their batteries or vehicles could be recharged “in minutes.”

As I headed home tonight (south on 101), VP1 was just getting on the freeway right into rush hour traffic.

You guys aren’t testing in out of the way places anymore. Your are jumping right into the “thick of things” with heavy traffic now.

I still don’t see any carpool stickers on any of the prototypes, so I guess you aren’t taking advantage of that EV perk yet.

Regarding traction control: I thought that using the traction control to limit tire slip was the way to achieve optimum acceleration timings. Spinning the tires makes for more noise, smoke and excitement, but does it really result in a lower time 0-60?

—

Andrew says: Our traction control system is intended to maintain traction for safety, rather than optimize acceleration.  In theory it is possible to tune traction control for best acceleration, but doing so reduces your safety margin for error, especially under varying road conditions (see Iain’s blog).  We’re happy with our result because, even with traction control enabled, the Roadster is still blisteringly fast and you don’t need to be a professional driver to demonstrate it.  

To James Anderson Merritt: I noticed that, too. I think the NY Times name recognition is the only reason Tesla linked to the article. I’m willing to cut Lawrence Ulrich some slack, though… he did put a Tesla photo at the top of the article, and attempted to do the “fair reporting” thing by listing potential alternatives. What he failed to do is convey the reality that most of those cars’ development is frozen due to lack of funding, and the ZAP-X doesn’t even have a prototype.

Today, any company that claims to be building a mainstream-compatible EV is able to get press attention. This problem won’t go away until someone actually starts delivering them.

Thank you for the info. I had not accounted for the 30% parasitic loss during charging.

FINALLY!!!!!! Some great and well awaited news from you guys Congrats hardly seem to be enough. Keep it coming ….

It is intersting to me that published ranges seems to exceed my model predictions I made many months ago. I expected range reduction to 200 miles for regular freeway cruising but it appears to be about 225 miles. For agressive freeway cruising I would expect 150 miles but it is 185 miles. Deviations stay under 20% to 30% error margin I expected but they are actually shifted much to the improvement. This is not very usual from my point of view to see so significant improvements in a real production target thing. Tesla Motors engineering team seems to have real love for the car they were doing.
Improvements seems to be mostly prominent for higher speeds. It looks like aerodynamic drag was somewhat reduced for production vehicles versus early prototypes. It also appears that battery discharge efficiensy ended up higher and probably energy losses are minimized for 55 - 80 mph range may be trading off with some efficiensy reduction at lower speeds.

Now it would be really interesting to see would Tesla Motors emerge as a car brand comparable to Porshe, Ferrari etc in next 10 - 20 years or they would try to transform into mass market car company. I still do not see how cost competitive mass market EV (car under $30 K price) is possible with today technology.

Will this car have a “limp” mode it will switch to before just stopping once your out of juice?

—-

Editor’s Answer: Yes - torque limits kick in at low charge. 

HOLY COW!!!
165 miles is your worst case!? That is unbelievable! GM and Toyota coulden’t even hit 130 in a best case scenario!
I guess I won’t have to worry about ‘toping off’ at Toby’s on my way to Duluth ; P
I could even drive to my cabin and back, which is amazing because we don’t have electricity up there!

Thanks for the numbers! Regarding the use of AC to thermally-manage the battery during charging: does the 75kWh number come down (if so by how much) when you charge less aggressively in, say, 7 instead 3.5 hours?

—

Editor’s response: See Andrew’s comment to Joseph above. 

Wow well done. It does look like my Lotus elise, but actually performs better go figure. Do you have dynos on this car? What is the total weight of the car? How much will the final production of this car cost? Is it streat leagal with airbags and so on?

—

Editor’s response: The Tesla Roadster comes with air bags and will meet Department of Transportation safety requirements. (We are in the process of completing our final safety tests.)  Pricing can be found on our Buy page and weight and other specs are available on the Tech Specs page.

congrats on your preliminary mileage stats! What a great base to start out from.

I can attest to the claim that they’ve been testing the roadster in real world conditions. A couple of months ago we visited a friend in the Western Addition neighborhood of S.F. By the front door was a note for our friend to contact her upstairs neighbor, he had a small request: Could he park his car in her garage spot for the night? Arrangements were made, and as we headed out for the evening he met us out front to gain garage entrance. Seeing his car was parked at the curb caused me to do a double take, it’s not every day you see a Lotus on the mean streets of San Fran. My double-take doubled to a quad-take as I looked closer, sure enough, it was a Tesla.

He told us he was a Tesla team member tasked with putting some real world miles on the mule over the weekend, nice job if you can get it!

My attempts to snag a ride went no where, but at least I got the picture! I felt like a photographer at Kitty Hawk circa December 1903, albeit with a cellphone instead of a Kodak Brownie.

The one question I didn’t get answered was - What would he have done with the unique, almost priceless, prototype if my friend wasn’t in town and the garage space didn’t materialize? Personally, I would have been satisfied to just bundle up, park it by Fort Point, and enjoy the experience of spending a night sitting in what history will judge as the seminal vehicle that ushered in the age of the electric vehicle.

A while back I had some concerns that the Tesla might have handling concerns because it has high efficiency tires.
I was assured that the tires on the Roadster have the magic ability to be both high performance and high efficiency at once, which is a great thing.

Another dilemma the Tesla tuners might have had would be suspension tuning for handling prowess versus efficiency.

I wonder if Tesla has “zero toe-in” for best efficiency and tire life? With “zero toe-in” the directional stability or “turn-in” may not be optimized the way one would want if efficiency wasn’t a primary consideration.
www.ozebiz.com.au/racetech/theory/align.html

I suspect the little details of Tesla suspension tuning could be part of the “secret sauce” that doesn’t get published readily.

I would like to congratulate Martin and his team for all of the great achievements found in the latest customer letter.
It all sounds like really good news. The range is back where you want it, successful crash testing, customer testing,
opening of the service center and a delivery schedule for the first Roadsters. Even though Michael Marks got the
pleasant job of signing the letter, I am assuming that these accomplishments were actually done during
Martin’s tenure as CEO.
Congratulations!

Where’s the heat? How does the driver keep warm in the winter? I haven’t seen any details on the passenger heating system, only the A/C. Not a problem in LA, maybe, but definitely a must have in The Windy City in January.

—

Editor’s comment: Not to worry, the Tesla Roadster comes standard with a heater. Here’s a bit of information about our heating and AC.

As much as I love the roadster and support your company, and hopefully will be buying a 2009 model, your cost per mile figures are just waaay off. I live not too far from your offices, and have PG&E. My current electric rates are 36c per kWh. A full charge of 75 kWh’s is $27 … for 230 miles is 11.7 cents / mile. 36c is admittedly a tier 4 rate, but a lot of people, especially perhaps in larger houses who can afford the roadster, are on tier 4. Even the current base rate is 12 c, which works out at 4 cents per mile. (Tier 3 at 22c/kWh is about 7-8 c/mile) Sure you can get 2 c / mile, but you’d better not be a PG&E customer and be on a base rate.

—-

Editor’s Answer: Check out PG&E’s E-9 rate.

Comment on the 75 kwh required to charge the roadster.

This number is incorrect, if it was correct then how could the 220 volt 70 amp charger charge the ESS in 3.5 hours?
220 x 70 = about 16.000 watts or 16 kwh. 3.5 hours x 16 = 52 kwh, real close to 53, so 53 kwh is what it takes to completely charge the pack. You pay 53 kwh to the electricity company per charge. Also if this wasn’t the case then the well to wheel calculations in the 21st century electric car document wouldnt make any sense!

Also the required energy for a car is quite easy to calculate:

(weight x gravity x Crol + 0.5 x CdxA x air density x velocity in m/s²) = energy in Newton

for the roadster this works out like this:

Frontal surface: 1.68 x 1.12 x 0.85 = 1.6
Cd = 0.30
Cd x A = 0.30 x 1.6 = 0.48
Curb weight: 1200 kg (for calculations 1300 kg incl. passenger)
Crol: 0.011 or 1.1%
Air density: 1.293 kg/m3
Gravity: 9.81 m/s
Average velocity (urban / extra-urban driving): 27 m/s

(1300 x 9.81 x 0.011 + 0.5 x 0.48 x 1.293 x 27²) = 366 Newton
To convert this number to wh/km you simply divide it by 3.6. 366 / 3.6 = 101.7 wh/km.

Compensation for inefficiency’s: / 0.75 = 136 wh/km. (due to regen the average efficiency is higher then 70%)

53 / 0.136 = 390 km or a little less then 245 miles. Pretty close for a back of the napkin calculation.

Im pretty sure i’m right about all the numbers, i derived the average speed from data from the EV1, the range at a constant 60 mph was pretty much the same as the driving cycle range. thats how i came up with the average speed in my calculation.

If the 75 kwh a charge number is correct then electric cars just aren’t as efficient as I thought.

The average CO2 emisions per kwh in the USA is 600 grams.
31 kwh per 100 miles = 193 wh/km –> 600 x 0.193 = 115.8.
This would mean that a toyota prius emits just slightly more CO2 per km (when looking at well to wheel efficiency’s)
which is 130.4 gr CO2 per km according to your document.

Still the roadster wouldnt use oil, wich of course reduces dependence on foreign oil, wich is a good thing. And you can of course choose how your electricity is made. By using solar cells which emit 50 gr CO2 (making solar cells is a energy intensive process) per kwh you’d emit less then 10 grams of CO2 per km in the roadster!

Comments anyone?

# Steve Casner wrote on September 26th, 2007 at 12:06 am
## Regarding traction control: I thought that using the traction control to limit tire slip was the way to achieve optimum
## acceleration timings. Spinning the tires makes for more noise, smoke and excitement, but does it really
## result in a lower time 0-60?

Another reason why traction control isn’t always the best way to quickest 0-60 is that many ICEmobiles have poor torque at low RPMs. This is particularly true for small displacement, high revving engines, and even more so with a big single scroll turbo.

To maximize acceleration, talented drivers will rev the engine, and orchestrate a careful feathering of the clutch to cause the tires to spin for a while then “hook up” for a launch with the engine already into the “meat” of the power band. This wears out the clutch, and wastes energy as heat in various places. With a Tesla, no such nonsense is required since the torque curve is so flat with everything available right off the line. Drivers who have mastered the art of “dropping the clutch” to maximize 0-60 times may scoff at the Roadster saying that it is “too easy”. Thus is the plight of mathematicians at the advent of the calculator, or horse drawn buggy operators as automobiles took over. The Ferrari owners with “F1 paddle shift” already have a taste of modernization, but the Roadster simplifies performance driving even further.

I am one of the few who have been lucky enough to get a customer test drive. I was told that the 0-60 time they saw while at Moffett Field was 3.[moderated] seconds with traction control on. They ran it a few times and the results were within a few hundreths of a seconds. That’s pretty amazing - really highlights the perofrmance aspect of electric motors.

—

Editor’s note: Darryl (VP of Marketing) doesn’t want to give up our specific 0-60 time just yet.

# Robin wrote on September 28th, 2007 at 9:04 am
## Comment on the 75 kwh required to charge the roadster.
## This number is incorrect, if it was correct then how could the 220 volt 70 amp charger charge the ESS in 3.5 hours?
## 220 x 70 = about 16.000 watts or 16 kwh. 3.5 hours x 16 = 52 kwh, real close to 53, so 53 kwh

Many split phase homes have 240V not 220V. (Some 3 phase businesses only get 208v)

220V is often used as a generic term to describe circuits with voltage in that neighborhood, but not actually 220V.

using 240V x 70A x 3.5h, I get 58.8kWh. A bit closer, but still shy of the 75kWh reported.
Perhaps they draw a bit more than 70amps? Or recharge time is a bit more than 3.5 hours if charging from empty to full?

Electric drag racing in San Diego come January… Be there or be square! :
members.cox.net/electric_dragin/

#
“milos wrote on September 28th, 2007 at 2:54 am

As much as I love the roadster and support your company, and hopefully will be buying a 2009 model, your cost per mile figures are just waaay off. I live not too far from your offices, and have PG&E. My current electric rates are 36c per kWh. A full charge of 75 kWh’s is $27 … for 230 miles is 11.7 cents / mile. 36c is admittedly a tier 4 rate, but a lot of people, especially perhaps in larger houses who can afford the roadster, are on tier 4. Even the current base rate is 12 c, which works out at 4 cents per mile. (Tier 3 at 22c/kWh is about 7-8 c/mile) Sure you can get 2 c / mile, but you’d better not be a PG&E customer and be on a base rate.

—-

Editor’s Answer: Check out PG&E’s E-9 rate.”

Thanks for the link - I usually read most of what’s on the site before I comment. But still on E-9 though, if you exceed baseline usage by just 30%, your cost TRIPLES!! Goes from 4 or 5 cents per kWh off peak (dep. on season) to 14 or 15 c off peak. Personally I don’t care if I’m paying 2 c per mile or 6, it’s a great car and a great, fun statement to drive. (And I think you’re going to take over the world!!)

Talking of cost and just a little off subject, the people who complain that the price tag makes it uneconomical, besides the obvious that most buyers are making a statement as well as wanting a great fun car, it actually is economical, because they don’t take into account the inherent capital value of the car. If you wanted to sell it after 5 years, say (god forbid), it would retain a huge amount of it’s value as the engine and body won’t depreciate much and the demand for a used model would be great. The main depreciable factor is that the battery would be middle aged.

PG&E’s E-9 Off Peak rate from midnight to 7 am is, at present, 5.0 cents per kWh from May 1st to Oct 31st and 5.8 cents per kWh from Nov 1 to April 30th. These figures are higher if you go for the E9B option which allows for EV charging to run through a separate, dedicated meter rather than the normal household one.

So as things stand, the ideal recharging sweet spot is this 7 hour nighttime slot. Assuming that recharging over 7 hours brings no improvement in efficiency, 75 kWh would still be the worst case / most energy required to fully recharge the Roadster. Assuming 240 V, you would need 45 Amps. 220V would need 49 Amps.

But as we know from the Bit About Batteries blog ( www.teslamotors.com/blog2/?p=39 ) good Li-ion management involves recharging to only 50% of the ESS’s capacity more often during the week rather than fewer 90% or 95% recharges (assuming your daily mileage needs allow for this)

So a possible weekly recharge pattern could be three 50% recharges for commuting and saturday errands plus a full recharge for Sunday motoring. The 50% recharges would be the first 7 hours of Mondays, Wednesdays and Fridays, with the big weekly recharge happening early on Sundays.

Assuming a linear relationship, a 50% charge three times a week would require about 40 kWh of AC for each recharge (which would be 26 Amps at 220V over 7 hours) giving 120 kWh for Mondays to Saturdays. Using the EPA Highway cycle only of 32 kWh per 100 miles, this 120 kWh would allow for a weekly commute (plus saturday shopping) of 375 miles (about 60 miles a day). Sunday motoring would need 75kWh (allowing for a 200 mile “highway cruising” round trip with air con/ heater as required)

Weekly recharging would require a grand total of 195 kWh.

Using the highest E9B winter rate of 6.4 cents per kWh, gives $12.48 per week in electricity (or 2.05 cents a mile).

If your mileage demanded 50% recharges for every weekday plus a full charge for both Saturdays and Sundays, the figure would be $22.40 per week. That’s 625 miles of commuting and 400 miles of leisure-time motoring every single week.

Anyone spending $22 a week on gas for 1000 miles of motoring?

At that rate you would run up 12,300 miles a year and be looking to replace or recondition the ESS after a minimum of 8 years. AFAIK the current design of ESS would be down to 70% of its original capacity after about 100,000 miles of motoring. Assuming you still only recharge at home, weekend trips would be down to 140 miles per day from 200 (however, in 8 years, parking lot chargers should be more widespread) and the weekday recharges would have to go up to 72% to maintain that 625 mile commuting range. What’s not clear is how / if recharging efficiency changes with ESS age. Neither do we know what electricity prices will be in 8 years time.

Mind you, by that stage we should have both Whitestar and Bluestar running on the latest generation of ESSs.

# milos wrote
# But still on E-9 though, if you exceed baseline usage by just 30%, your cost TRIPLES!!

More info on the E9 rating system

www.pge.com/tariffs/pdf/E-9.pdf

Page 6 poses some interesting questions but I can’t seem to find relevant info to select the appropriate territory. Is it T? If so, then I think that EV users would have the first 26.26 kWh (130% of 20.2 kWh) of any daily Off Peak recharge in the Winter charged at 6.4 cents per kWh and 16.11 cents for any additional kWh. In the Summer it would be the first 14.56 kWh (130% of 11.2 kWh) charged at 5.6 cents per kWh and 15.34 cents for any additional kWh.

(We really need a proper blog entry on this next year from one of the Roadster owners.)

So going back to my previous post, if the Roadster requires 40kWh of AC each day from Monday to Friday and a further 75 kWh on Saturdays and again on Sundays, then Summer electricity costs will be $43.76 per week and Winter will be $38.54 per week.

So roughly $40 for 1000 miles of motoring.

Assuming that I’ve been using the correct figures and also $3 a gallon for gas, you’d need to get about 75 mpg (EPA Highway) to beat that.

Presumably they will calculate the mpg equivalent for the Automotive X prize using energy rather than dollars.

Oh hang on…..Still not right.

Assuming territory T and the rate B for E9 we have:-

In Summer:

The first 14.56 kWh is charged at 5.6 cents per kWh (0 to 130% of the 11.2 kWh baseline)
The next 7.84 kWh is 15.35 cents per kWh (130 to 200%)
The next 11.2 kWh is 24.35 cents per kWh (200 to 300%)
Any additional kWh are charged at 29.06 cents

So 40 kWh costs $6.61 for each weekday and 75 kWh costs $16.78 for Saturdays and Sundays

So weekly costs would be: $57.11

In Winter:

The first 26.26 kWh is charged at 6.4 cents per kWh (0 to 130% of the 20.2 kWh baseline)
The next 14.14 kWh is 16.11 cents per kWh
The next 20.2 kWh is 25.11 cents per kWh
Any additional kWh are charged at 29.82 cents

So 40 kWh costs $3.89 and 75 kWh costs $13.32

Giving $46.54.

So now the figure is an average $52 for 1025 miles. 625 of those miles are weekday commuting @ EPA Highway and the remaining 400 are for weekend “highway cruising” with air con/ heater as required.

As always, your mileage and recharging efficiency / costs may vary.

However, if these calculations are correct, I think the “less than 2c per mile” figure on the Home Page should be revised.

This pricing structure favours smaller daily charge-ups rather than bigger charge-ups every few days, particularly in winter. Interesting. If you weekday mileage is quite low and you are planning a long weekend trip, it would pay to top up the battery gradually over the preceeding week rather than all in one go early Saturday morning.

Can Tesla Home Fast Chargers be given simple LCDs like gas pumps, showing a diary of charges incurred? Or does the car do all that? Some sort of EV electricity cost calculator would be very handy - even an Excel spreadsheet would do the trick.

Forced to use the daytime tarrifs, Parking Lot chargers would be more expensive, even assuming minimal maintenance costs. EV owners may therefore view them rather like emergency gas cans and generally try to avoid having to use them.

I hope Martin Eberhard revises his cost-efficiency comparisons between EVs and vehicles fueled by other means in his presentations. I would be particularly interested to see how the “well-to-wheel” efficiency analysis comes out using the empirical data that Tesla now has. How many square miles of southwestern desert (or offshore ocean surface) would we need to devote to solar power arrays (or wave power converters, respectively), in order to offset the power used by all Roadsters that are likely to be sold prior to the arrival of WhiteStar? How many square miles, if all the ICE personal vehicles on the road were converted to Roadster-class EVs?

This is fantastic news! Your engineers have done a stellar job staying true to your performance and range goals. I eagerly await more information on Whitestar and Bluestar, while I continue to build my deposit fund in great anticipation.

Have you considered EEStor super capacitors. They claim 10x charge density per kg as lead acid and quick charge times of 4 minutes on their supposedly soon to be perfected capacitor

Why don’t you integrate a solar panel into the body design? DBK Solar has a panel rated at 3000 KWH, this would extend the range and might alleviate the need for recharging, in certain applications. I live in Florida, I drive 10miles to work in the am, 10 miles home in the afternoon, with a solar panel installed, I would never have to plug it in.

This is what the USA needs in the worse way. Thanks for the efforts and determination. I absolutely love these cars and use the beuatiful red roadster as my wallpaper for my PC monitor! One day I hope to be able to afford your vehicle, but in a family built style. Go for it all the way guys, and God Bless your efforts.

tom boyd: Tesla knows about EEStor, and is as excited about the possibilities as anyone. There’s just the small problem that you can’t actually buy EEStor capacitors… they seem to only exist on paper and in press releases. That won’t do for building real cars

# Malcolm Wilson wrote on September 30th, 2007 at 4:03 am
## More info on the E9 rating system
## www.pge.com/tariffs/pdf/E-9.pdf

If you install (PV) Solar then you can either negate your bill entirely or at least keep yourself away from the “above baseline” multiples.
www.ongrid.net/papers/PaybackOnSolarSERG.pdf

When considering the size of your solar system, your power needs (including recharging a vehicle), and the shading on your property you can consider various rate plans. Keep in mind that E9 is a little bit “solar unfriendly” in that the peak times are 2PM-9PM which moves the curve later in the day when you may not have sunlight to generate power at the higher rates.
For comparison, E6 plan has peak rates from 1-7PM, and E7 has peak rates from Noon-6PM.
So, depending on what you do with solar, an E7 rate might actually be more attractive than E9.
(In case you missed the point - you want to generate PV power to send to the grid at peak daytime rates to offset the nighttime power use you at hopefully lower rates).

It is not only the peak time to sunlight time alignment to think about. You also want to think about peak time to usage time. If your house sits empty during the day, but then everyone comes home at 6 or 7pm and starts using power, the rate schedule can have an impact.

One “gotcha” I ran into was due to the changes in daylight savings time. PG&E sent a notification letter saying they were not going to reprogram the existing meters so my E6 schedule shifted (effectively) to peak from 2PM-8PM during the revised daylight savings because it was using the old daylight savings schedule. What this meant is that the family came home and started dinner, doing laundry and other such things at 7PM, but the meter though it was still 6PM (due to the daylight savings shift) so we were using “peak” power rather than “part-peak” during that hour period.

With different peak, part-peak, and off-peak schedules for different seasons, as well as above baseline multiples, multiple rate types, and daylight savings to consider, it can be complicated to figure out what is optimal. Further the PG&E rate schedules change. For instance, when I got solar, E7 wasn’t available, but now it is back again.

Do the mileage numbers reflect 1 or 2 people in the car ?

# TomJ wrote
# Are you actually proposing someone is going to drive their Tesla 1000 miles a week?

Not really, just thinking out loud about the “2c per mile” figure. If someone goes for the dual leather interior and that kind of mileage, they’ll be spending so long behind the wheel that the Tesla logo from the seat will be embossed into the skin on their back

Hmmm….Tesla hats, tesla tee shirts, tesla tattoos…..

Hopefully Tesla isn’t using Matsushi-ta/Panasonic Li-Ion cells right now!:

Links:
www.bloomberg.com/apps/news?pid=newsarchive&sid=a0HJMiIpUo04
www.eetasia.com/ART_8800482028_765245_NT_19ac7134.HTM
.

Malcolm Wilson wrote: “At the moment, the Roadster can be programmed to charge to 50, 90 or 95% battery capacity.”

Err. . . The highest amount of charge the battery will accept, by definition, would be 100% wouldn’t it?

Last I heard — it was a while back — the options were 50, 90 or 100 percent. The idea would be to keep it charged at 50% for your everyday driving (assuming your everyday driving allows for that), and it would extend the battery’s service life. Then if you needed to take a longer trip you would increase the charge to 90% (preferably) or 100% (if necessary) before starting.

From where I sit, the maximum energy that the owner can program the car to accept has to be 100%. Calling it anything else would be a bit silly. However. . . If Tesla really wanted to go down that route, then I suppose the next logical thing would be: call the charge levels 50%, 100% and 110%. Then it would be understood that 100% is the usual limit, but you could “crank it up to eleven” for that extra push over the cliff.

Tony Belding wrote: “Last I heard — it was a while back — the options were 50, 90 or 100 percent.”

Actually the defined charge levels where 50, 90 or 95% of battery capacity. Take a look at “A Bit About Batteries” blog posting from November 2006. Pushing the batteries to 100% state of charge would greatly reduce the number of battery charge cycles therefore the maximum charge level will be limited to about 95% SOC.

More breaking news - I just read something exciting - though I suspect the engineers at Tesla may already know about this ….. (not sure which thread to post to, but this seems as good as any)

Japanese Trade Show Introduces Quick Wireless Recharger - A prototype wireless recharger created by the joint efforts of Seiko Epson and Murata Manufacturing LTD will be on display. The product will reduce standard charge time [for mobile devices] from one to two hours down to ten to 15 minutes.

www.physorg.com/news110546631.html

It sounds like this is meant for all mobile devices like laptops, phones etc. Since the Tesla runs on these same batteries but just thousands of them, wouldn’t it be possible to build refill stations with thousands of these chargers that would each charge up a few batteries and then you could cut the Tesla recharge time down to the same 10 or 15 mins?!!! Or am I just dreaming? If it weren’t wireless I guess you could create a mass charging unit and modify the battery assembly/connectors to take the charge in parallel, but being wireless I don’t know if that makes it easier or harder (each set of a few batteries on a different wavelength?). Also, I have no idea if a super quick recharge like this would affect the reliablity or durability of the batteries, though I would think not.

Re: Mazda Premacy Hydrogen RE uses the latest version of the Wankel internal combustion engine fueled by hydrogen or gasoline, with an electric hybrid power train. The H2 tank is very large but gives only 120 miles range - and that’s an improvement over the previous version.

The lease is $3,500 per month - ouch! That indicates a vehicle cost much higher than the Tesla Roadster, about $175K. Most of that high cost is due to the 10,000 psi carbon fiber compressed H2 storage tank. H2 fuel cells would be more efficient and give a better range, but would nearly double the price - still need those expensive H2 tanks. For all that, H2 fuel is even more expensive than gasoline on a “gallon of gas equivalent” (GGE) basis. Driving on H2 costs more than gasoline, driving on “electric fuel” costs far less.

Now we can see why Martin went with much more efficient much less expensive LiIon batteries instead!

Sweet!

From what I’ve been reading about the next Gen Lith-ion battery, that would extend the range an additional 30% to 318 Miles. Whether or not that calculation is accurate, it highlights one very important potential of an electric vehicle over ICE:

You can increase your mileage by simply including a better battery.

And yes, I know I’m preaching to the choir

If you wanted to increase the range of your Ford F150 by an additional 30% distance, you’d have to include a backup fuel tank of some kind. That would add increased weight as well as taking up additional space.

With advances in battery technology, you can effectively store more “fuel” without added weight or space usage.

The potential of electric vehicles is absolutely amazing.

I would like to know if you are going to enter in the X- Prize race ? If this is the case, I have an idea, that will enable you to regenerate your batteries on the move , without pluging in your vehicle. If you are interested contact me [Contact details deleted]. I would really like to see you win the prize!

Thanks , Mel Jamison.

Today I visited your website and I am impressed by some genuine effort that is going towards making a reliable, long distance electric car (which is what matters most to the consumers besides the price tag and affordability in the long term). However there is something which has been bugging me as far as design of electric/ hybrid cars goes. All the car companies which manufacture electric/hybrid cars advertise in big bold letters that they are using a part of breaking energy to regenerate electricity which goes in charging the batteries. However no one talks about the tremendous amount of energy potential which could be harnessed when the car is running by converting a part of the rotational energy of the wheels in to electricity by using Michael Faraday’s Electro-Magnetic induction to create electrical energy and sending it back to the batteries. It could really increase the range of your car by atleast 50% if it has not been implemented in your car already. I do not know if it has already been implemented or not but I thought I should bring it up.

I wish your company well and hope that as it becomes profitable in the future it would work more towards producing affordable electric cars for the masses!

With Best Regards

Amitesh

#Amitesh Kumar wonders about “converting a part of the rotational energy of the wheels in to electricity by using Michael Faraday’s Electro-Magnetic induction to create electrical energy and sending it back to the batteries.”

#Tom Young asks whether the Roadster has “any type of alternator, or anything can sustain even a minimal charge to increase battery life per charge.”

Short answer: because of inefficiencies, both proposals require more energy than they generate.

Longer answer: These links might be worthwhile to review–

www.teslamotors.com/blog2/?p=24

en.wikipedia.org/wiki/Conservation_of_energy

For a personal example, one might compare the experience of riding a bicycle with and without a lighting dynamo attached to gauge the relative energy required:

en.wikipedia.org/wiki/Bicycle_lighting#Dynamo_Systems

Phil H asked on September 30th, 2007 at 10:46 pm whether the PG&E baseline allowance is calculated every day or on a monthly basis. The answer is monthly. As you surmised, the daily baseline allowance is multiplied by the number of days in the billing period to get the total baseline allowance for that period.

A couple of other points: In all the PG&E tariffs so far, the surcharge amounts for Tiers 3-5 are the same for all periods of a Time-of-Use tariff (E6, E7, E9). Therefore, the total surcharge depends only on the total kWh for the billing period, and not on the time of day at which you used the power. Using a small solar system to chop off those higher tier kWhs is a great way to get faster payback.

The PG&E 2007 General Rate Case was recently settled, which establishes new tariffs for November 1. I have not seen the new tariffs yet, but I heard that during the rate design there was a consideration for the tier surcharges to be less for E9.

# Steve Casner wrote on October 9th, 2007 at 12:24 am
## The PG&E 2007 General Rate Case was recently settled…

www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2007/09/08/BUSGS1D5U.DTL
www.pge.com/regulation/GRC2007-Ph-II/Pleadings/PGE/2007/GRC2007-Ph-II_Plea_PGE_20070316-01Atch01.pdf

Lithium Iron Phosphate battery test report:

zeva.com.au/tech/LiFePO4.php

125 mile/hour limit???? Everyone knows that you can’t fully test a roadster unless it is going at least 140 mph with 6 cop cars chasing you! I’d tell you to refer to the OJ Simpson chase but of course he couldn’t even get his vehicle up to the speed limit, let alone to 140mph. Well I guess out of the gate 125 mph will be sufficient. Or at least you will have to let Andrew bring a roadster back to Colorado so he can race me in my Honda S2000 on the straigh away highways of I-76 on the way to the big city of Brush, CO. I look forward to your next version release that makes it to 140 mph!! Nice job by the way on the battery and mph increases and efficencies, looking good!

# david moxness wrote on October 11th, 2007 at 4:25 pm
## www.ecorazzi.com/?p=4133
Yeah, I posted that link over on a different Tesla blog back on October 9th:
www.teslamotors.com/blog5/?p=55

Simple question % range reduction for using th Air Conditioner?

manual trackback
Great post about a great car. I hope, that some day we may be able to buy a Tesla over here in Germany.

Hello ,

When will you put your engine in a Smart Roadster. It seems too me be the perfect platform for a less expensive more mass-market Tesla (compare to your present “Lotus”). Project Kimber has bought the tooling for the Roadster and say will restart production of the car in 2007 but the project has run “cold”. Something for Teslamotors to buy/license?

Best regards
Mattias

Mattias: Tesla has never shown any interest in putting their technology in a car designed for an internal combustion engine. The Tesla Roadster, and the future WhiteStar sedan are both original designs, intended right from the start to be an EV.

EXCELLENT NEWS!!!
Now that’s what I’m talking about… I have followed Tesla’s progress from the begining and i’m impressed.
I can’t wait to test drive a Tesla convertible and get my name on that list ASAP.
I think the Tesla is just what America has been waiting for !!!
Keep Up The Good Work.
Kathy Hilding

Does Tesla Motors have plans to include recapturing energy during deceleration?

Very impressive figures but I still think the real ‘worst case’ mileage will be a lot worse than 165 miles. When you give the car to magazine testers or to a TV programme like the BBC’s Top Gear they’re going to thrash it around a race circuit using full acceleration and heavy braking to compare its time to other regular sports cars. I think the Tesla will do pretty well for lap times in these tests but there’s no doubt that its mileage will suffer badly. I wouldn’t expect much more than 100 miles of this sort of abuse before the battery will be flat. In the real world we don’t often drive like this but flat-out, illegal charges from town to town at dead of night will probably see similar mileage results. I don’t think this devalues the car at all but we should just be careful with terms like ‘worst case’ because somebody will always prove you wrong.

Andrew Kelsey: I agree that if you count the track (or track-like conditions), the range could be a lot worse. It’d be a fun 60 miles, though

On the other hand, tracks present a good opportunity to place a very high-powered charger (much more than the 240v 70amp home charger). A track will already have commercial-grade service. Standard lithium ion cells can go from 5% to 80% in 30 minutes, if there’s enough power available and the support equipment doesn’t overheat. Obviously, that’s still way too slow for an endurance race, but it’s fine for anything that fits in a Tesla’s range.

It would probably be in Tesla’s best interest to get some kind of “Track Charger” built before handing the keys to Jeremy Clarkson or any other tough reviewer.

# Andrew Kelsey wrote
# When you give the car to magazine testers or to a TV programme like the BBC’s Top Gear they’re going to thrash it around
# a race circuit using full acceleration and heavy braking to compare its time to other regular sports cars.

Looked at from either an mpg or miles-to-empty-the-”tank” perspective, the Tesla will still be significantly better than the equivalent ICE sports car, given a similar thrashing. It would be great to see a Porsche (or similar) only given the volume of petrol equivalent to 53kWh. Get it to race the Tesla and see which one hits empty first.

Assuming that petrol is 9.7kWh per litre, a US gallon would give 36.7 kWh and an Imperial gallon would give 44.1 kWh.

So in the US, any car racing against the Tesla could only be given 1.44 gallons, and in the UK it would be 1.20 gallons.

The Tiptronic S Porsche 911 Turbo (0 to 60 in 3.9s) gets 14.3 mpg (urban) and costs about twice as much as the Tesla Roadster.

A 20 mile twisty road race between these two should sort things out nicely

# David Kosowsky wrote on October 21st, 2007 at 8:08 pm

## Timo and Don, I think the A/C load is mentioned in an earlier post.
## I believe it’s about 1KW. % range reduction would depend on A/C settings
## (how cold), ambient environment, etc. If 1KW is accurate then it may be as
## high as ~10% (city driving in 95 degrees with 90% humidity).

Was that A/C load or ESS “climate control” load? ESS has its own A/C which is always on.

Anyway, 53kWh battery with 240 mile range at highway speeds means 240/60 = 4 53/4 = 13.25kW /h. One kW more means 14.25kW which in turn makes range about 223 miles. You lose about 17 miles out of 240 or about 7%. Roadster had bigger range in city, so there relative effect would be greater.

This course depends of how good the weather is and how well insulated the car is. If weather is optimal you lose practically nothing. 1kW A/C is quite powerful A/C, so I believe power consumption will be less than that in normal California summer conditions. I have one electric A/C at my house and it has only 850W power rating. It is not very powerful as house A/C but could freeze Roadster size passenger space in matter of minutes (if not seconds).

Chris in Victoria: Richard Stone is failing to consider the inefficiencies of extracting and refining fossil fuels.

It may seem too easy to be true, but the best way to assess the efficiency of something tis to measure the total cost of ownership. In terms of cost per mile, diesel is far more expensive than electricity, so one can accurately conclude that, at least from a fuel perspective, EVs are vastly more efficient.

Realistically, measuring fuel efficiency alone is purely an academic exercise.

The best way to measure the practical efficiency of any vehicle is to figure out how much it costs to go 100,000 miles, including the cost of the vehicle itself. Versus a Mazda MX-5, the Tesla Roadster is just awful here (unless gas suddenly jumps to like $35 a gallon) Versus other exotic sports cars, however, the Tesla Roadster has no competition.

There’s an intersection point where gas prices are high enough and EVs are cheap enough that an EV is the best choice. As Tesla moves down-market, their success at swaying budget-conscious consumers hinges on their ability to produce cars that perform at a level expected for their class while remaining competitive from a “Total Cost of Ownership” standpoint.

# Tim W. wrote on October 22nd, 2007 at 3:14 pm

## Yes we’ll face greater demands for electricity, but that’s a lot better
## than greater demands for oil. We can find new and better ways of
## making electricity (especially good when distributed) but we can’t
## just make more oil… (AFAIK)

We can make oil. From different vegetation and biotrash, but that is enormously inefficient and making fuel/petrol that way also needs huge areas to grow these plants, which in turn weakens biodiversity and is out of growing food.

Best way is to use solar. Even solar power satellite (check wiki) would already make more money than constructing it does with current energy prices. Only reason _not_ to do that is that oil/coal/hydro/ground-based solar etc. is so much cheaper. But that will change. Launch costs will drop with new technology and maybe even in near future we will have space elevator which would make solar power satellite way cheaper than nuclear power plant (/GWh) . Solar energy is only energy source that is virtually unlimited. Eventually we will have Dyson sphere around Sun, but that is still distant future.

For “Chris in Victoria”: The analysis you quoted is deeply flawed. While it included the efficiency in producing and distributing electricity, it does not include the efficiency of producing and distributing gasoline or diesel fuel, thus biasing the results. Note that if you remove the powerplant and distribution efficiency, the electric car by itself gets 46% efficiency, more than twice the efficiency of either gas or diesel cars. Also consider - what if the electric power came from a hydroelectric plant at 90% efficiency - the result would still be 40% overall efficiency, winning even against that highly biased argument.

Worse, both the production and the distribution of petroleum fuels is far less efficient, energy wise, than the production and distribution of electricity. If that author had done a fair analysis and included the efficiency of refining (including the electricity needed to run the refinery!) and the efficiency of trucking fuel to the stations, the results for both gas and diesel would be far far worse. Consider also that the amount of electricity needed to make a gallon of gasoline will propel an electric car almost as far as a gallon of gas will propel a gasoline car.

That author is just blowing smoke, hoping no one will notice his obvious bias in favor of internal combustion, and how irrational his argument is.

# using 240V x 70A x 3.5h, I get 58.8kWh. A bit closer, but still shy of the 75kWh reported.
# Perhaps they draw a bit more than 70amps? Or recharge time is a bit more than 3.5 hours
# if charging from empty to full?

Could the answer be RMS? The batteries are DC. The power is AC. An AC circuit delivering 240V is delivering 240V RMS, which works out to (240/0.707)V = 339V peak-to-peak. Multiply that by your 70A and you get: 71,190W. I don’t know if thisis the right math to be using, but it comes awfully close to the numbers they are sticking to, and when rectifying AC to DC you tend to get the peak-to-peak voltage value, not the RMS value.

Battery chargers take much more of their power near the peak of the sinusoidal voltage, thus the actual power draw would be higher than the RMS current and voltage would indicate.

It is surprising how large the loss is from utility to battery energy. 70% is quite large. It would be informative if Tesla would give us an audit of those losses. i.e how much is charger electronics loss, battery charging & discharging losses and cooling losses. The electronics should be at least 95% efficient, and it shouldn’t be significant if it is fed from a 220v or 240v utility supply. One consideration is that 70% conversion efficiency is presumably over the full discharge cycle from 95% to 2% SOC. If that is how the EPA rates fuel economy of BEV’s, that is a false calculation. For instance with NiMH batteries, charging efficiency is about 75% over the full discharge cycle. But from 40-60% SOC, the charging efficiency is over 95%. So for the typical City driver, with 30 miles range on a 150 mile battery, they can charge from 40-60% SOC and get their 30 mile or less daily range. Normally you would plugin each evening and that 20% discharge can be replenished at over 90% efficiency and with a low output 120vac charger @ an average of

# Oliver wrote on October 26th, 2007 at 8:26 am

….
## The company is called Steorn, and their website is simply www.steorn.com

Steorn is very very likely to be a hoax. See en.wikipedia.org/wiki/Steorn

I am impressed with the progress you have made with the electric motor and with the sports car. When will the 4 door model be unveiled? Will the system ever be transferable to other cars and trucks? What’s in the future future?

Thanks
Cam

A.H.: The Tesla Roadster has a 245 mile range. Even if it’s not fully charged, you can still go quite a long way For extended power outages, you can use the mobile charging kit to charge up elsewhere (though you’ll want to find something much more than your standard 115volt 15amp outlet, otherwise it’ll take a long time).

EPA Test Miles Recharge Energy
kWh/100mi
City cycle 252 30
Highway cycle 236 32
Combined result 245 31

Any notice this chart and figure out the cost of the enrgy used to drive 100 miles? This depends on where you live and your utility cost but the avergae is about $0.13 per KWh x 32 = $4.16/100 miles…. Is this the correct way to figure this? Now I figure this is way less than any $3.50 per gallon gas price for a vehicle that does not nearly achieve a 100 miles per gallon! You do the math or tell me I am wrong here…

Great work Tesla!

Malcolm Wilson wrote:
#Looked at from either an mpg or miles-to-empty-the-”tank” perspective, the Tesla will still be significantly better than the equivalent ICE sports car, given a similar thrashing. It would be great to see a Porsche (or similar) only given the volume of petrol equivalent to 53kWh. Get it to race the Tesla and see which one hits empty first.

I’d agree with you Malcolm, but if we’re going to compare in those sort of cost terms we would have to include the cost of a replacement battery wouldn’t we. We know the electric car is much more efficient at the point of use but it would be disingenuous to ignore battery replacement at say 100,000 or 120,000 miles. Top Gear might make some reference to the low day-to-day running costs but I think they’ll give much more prominence to the limited range per ‘tank’ of fuel. Nonetheless I think they’ll be quite impressed overall, as they should be. I’d expect the Tesla to put up a pretty good lap time in the Stig’s hands.

Malcolm Wilson wrote:
#Or you could do something like the Energizer Bunnies. Give all the cars 53kWh-worth of fuel and see how far they go at a steady 60

That would be an interesting experiment Malcolm and we all know who would win by a country mile, of course. The problem is that the general viewing public has no interest in the energy equivalence between petrol and electricity. This might help educate them, of course. It makes better television, though, to thrash the cars around the track until the Tesla runs out of power…probably around 100 miles I’d guess. It shouldn’t take them long.

If we want to compare cars on a cost basis let’s have a complete rundown showing anticipated servicing costs for the Tesla….very low…..and anticipated battery replacement cost….likely rather high. Then factor in cost of fuel per annum and maybe allow something for the saving on congestion charge for those living around London and working there. I suppose we’d also have to take into account depreciation on the original purchase, which is almost impossible to calculate for the Tesla, especially since it won’t be sold in the UK.

At the end of the day I think we have to face the fact that the Tesla is unlikely to be a sensible purchase in pure economic terms, even if you compare it with a higher-priced Porsche. The Whitestar should make much more sense in those terms but the Roadster is really an emotional purchase. People who buy it will do so because they want to further the cause of EVs for one reason or another and enjoy themselves in the process. Of course the potential is there to save money in future but it can’t be fully realised with the Roadster. It’s just too soon.

That’s interesting Raymond. Did you include any estimate for battery replacement cost? I know the battery may last much longer than 100,000 miles, with all the temperature and other controls the car has, but I think it would be unfair to make the comparison without allowing some figure for this. I also think it might be better to compare the car with a Lotus Exige, preferably the fastest model available. That would be a more direct comparison with a car that could serve a similar purpose as well as being usable for longer mileage trips. What did you allow for depreciation on the Tesla, bearing in mind that after 4 years at your mileage it will be getting quite close to the battery replacement time?

I wish I could seriously consider the economic merits of Tesla ownership but unfortunately it’s just not an option for me.

Hey Dirk:

Figure it out this way:

Calculate the cost per mile from your electrical bill. In the numbers you gave, that works out to $0.0416 cents per mile. In my case, it works out to $0.03 cents per mile.

Calculate the cost per mile the “most efficient vehicle of ” would have at your local gas pump prices. In my case, the prices were calculated at $0.99 cents per litre. Specifically, the vehicle I used was the Toyota Prius (45 mpg). That works out to a cost of $0.08 cents per mile (if memory serves correct). My truck - Ford F150 - runs in at about $0.18 cents per mile.

If costs were to remain constant, the difference in fuel costs (between the Tesla and the truck) for 120,000 miles is roughly $20,000. That’s some pretty significant fuel savings.

#Andrew Kelsey wrote on November 11th, 2007 at 6:20 am
#I think we have to compare like with like here. Of course if you have a big truck it will
#use a lot of gas. A big truck would use a lot of battery power too and wouldn’t have
#much range as it wouldn’t be aerodynamic. The Tesla needs to be compared with
#similarly sleek, aerodynamic cars like the Lotus Exige or Elise. Of course the
#savings don’t look quite so good then but we need to be intellectually honest
#with our comparisons to avoid looking like EV zealots. I’m as keen as anybody
#for EVs to make economic sense but the truth is they don’t quite do that just yet.
#Don’t let that stop you buying one though!

Comparison to Lotus Exige and Elise isn’t quite accurate either. Better comparisons would be done with the Porsche 911 turbo, the mercedes SL55 AMG, or the Ferrari F430 Spider . An ICE (internal combustion engine for those who don’t know) with enough horsepower to push a car from 0 to 60 in under 4 seconds is going to suck down a bit more gas than the ICE in an Elise. HOWEVER, it has been said by members of Tesla Motors that a more powerful electric motor is more efficient than an a less powerful one, which is just the opposite for ICE’s. So, that brings up a question: will the less powerful electric motors to be put in mass market electric cars be less efficient than the electric motor in the roadster, and how much less efficient- a neglible amount?

Nice writeup TomJ,

Refreshing to hear the economics put in a new way.

You should share over here: www.teslamotorsclub.com

# Thor J wrote on November 13th, 2007 at 12:14 pm

## At first, I was really wanting the A123 batteries for the charge lifetime;
## if a $100K car lasts 100K miles, thats $1/mile. Ouch.

## If the pack costs $30K, that goes down to 30cents/mile, which is under
## the IRS regs, but still sounds pricey compared to gas.

I’m expecting replacement battery pack being cheaper and better. It takes a while to drive 100000 miles with the car that can’t be used for regular long road trips. By that time both battery technology and price should have gone down a lot. Maybe $5000 for similar performance battery pack or $30k, but a lot better than current tech.

Commuting 100miles a day average (which is a lot) you would still need 1000 days which is nearly three years. With normal driving I expect that to be closer to 40-60 miles a day for normal driver with long distance from home to work, which makes it six years. Six years is a long time for technology that is advancing this fast.

## Then again, at 100K miles, it isn’t useless; it just has a range of 100 miles.
## That’ll do. (But nobody lists capacity curve after 50% capacity is gone, so I
## don’t know how much longer that’ll do).

IIRC Teslas definition of “useful battery” is 80% of its original energy capacity, not 50%. And original range is 245, not 200. 20% out off 245 is 196 so you would still have 196 mile range at 100k miles.

I agree that A123 and Altairnano batteries are technically better, but they cost you a lot more than ordinary high energy density lithium ion batteries. Would you like to have 300000$ car instead of 100000$ car? Also Altairnano batteries and A123 batteries have weaker energy density than batteries used by Tesla. That would probably make battery pack bigger than Teslas even with battery climate control and safety features removed. But after six years, who knows? Those “high tech” Altairnano batteries might be considered relics from stone age by that time.

I have to scratch my head at the nonsensical discussions about the mileage Tesla roadsters might be driven during commuting to work and how long it will take to go 100K miles. I’m betting that most buyers of the Tesla roadsters are not “commuting to work” in it. I’d be surprised if the average yearly mileage on a roadster goes much over 2K mi, which is about what we put on our SLK55 AMG. People worried about mileage and commuting to work are probably buying Priuses. Now, if we could just talk AC propulsion in converting the SLK to the roadster’s electric drive we’d really be happy and I really would not worry about justifying a payback period or any of that other economic crap.

Darrell Lookingbill: It depends on the power source. With the home charger running a 240 volts / 70 amps, about 3.5 hours. With a normal 115 volt / 15 amp wall socket, it’s roughly 35 hours.

Obviously, the ideal situation is to fully charge it every night while you’re sleeping.

# OzoneLevel wrote on November 16th, 2007 at 5:12 am

## I have to scratch my head at the nonsensical discussions about the mileage
## Tesla roadsters might be driven during commuting to work and how long it will
## take to go 100K miles. I’m betting that most buyers of the Tesla roadsters are
## not “commuting to work” in it. I’d be surprised if the average yearly mileage on
## a roadster goes much over 2K mi, which is about what we put on our SLK55 AMG.

I would be commuting to work if I wouldn’t be living in walking-distance of my workplace. And I could afford roadster, but I think I wait for Whitestar. No need for expensive toy car. But anyway, that Roadster is only about 75k euros, which isn’t so expensive that people that can get it wont be going to the work daily. Some quite surprising people have expensive cars, like one of the secretaries of my workplace (Mercedes CLS -series car).

## People worried about mileage and commuting to work are probably buying Priuses.

Prius, no thank you. I’m not “green” enough to buy something like that.

## Now, if we could just talk AC propulsion in converting the SLK to the roadster’s
## electric drive we’d really be happy and I really would not worry about justifying a
## payback period or any of that other economic crap.

Maybe we could get AMG to make SLK electric. See what they can do to it. Or Brabus.

You should really consider selling in the Uk,

Personally if I could get one in the UK, it would be for commuting to
work, no more London congestion charges, no more tax on fuel…

$100k is less than £50k, for a high performance sports car (0-60 in 4 seconds!!!!) that sounds very reasonable to me…

With the cost of petrol here being around £1 a litre, it makes it an even better buy!

A bit about “high-tech” batteries and why Tesla is _NOT_ using them.

I just calculated what it would cost to make Tesla ESS using A123 batteries.

They sell 6-cell “developer kits” for $129.00.
Each cell contains about 7.59Wh energy (3.3V, 2.3Ah) and weight 72g (in developers kit)
You need 6983 cells to get 53kWh. That weights about 502.7 kg (not too bad, Tesla ESS is about 450kg)

So this far everything looks good. With added safety (which doesn’t require as much as Tesla ESS), I’d say final weight for 53kWh is maybe 550 kg which is slightly less than 10% of car overall weight more. Can’t calculate size, it might or might not be bigger than Tesla ESS, but difference should not be too much.

Now the price: 6983 / 6 = 1163.8 * 129$ = 150130.2$

OK. So ESS alone would cost 1.5 times the Tesla Roadster.

Altairnano has slightly worse weight/kWh ratio and they don’t even bother trying to sell their batteries in their website.

Maybe, just maybe, we should wait for those prices to go down. But OTOH that is about all we need to wait for. These batteries offer better power density, better cycle life and faster charge (much faster). So in next few years things might be quite different.

# David Tramblie wrote on November 22nd, 2007 at 10:32 pm

## Is it feasible to have inside the front air damper of the car small fan-like
## turbines that could generate electricity while the car was on the road.

Short answer: No.

Longer answer: There is always price to pay for this kind of systems. You end up losing more than those generators generate. Only things that can actually generate more energy than they end up losing are systems that capture energy that is coming to the car from sources _other than the car itself_. Like sunlight. But solar panels are so weak that their effect is negligible to cars energy consumption. It could be useful to have solar panel “blanket” that you could apply when car is parked to slowly recharge car.

Hopefully, the momentum created with this rollout will continue. It would be very sad if this automobile didn’t go into full production because of some interference from but Big Three (or from government agencies).

Would love to see more info about the sedan for 45K. It’s obviously meant to rival GM’s Volt. This is the market, gentlemen, that needs to be focused on..

Good luck, full speed ahead!

Tom

# Roel wrote on November 26th, 2007 at 2:35 pm

## I suspect you guys know everything there is to know about batteries,
## but I would like to mention what I thought (knowing nothing about the
## technology) seemed like an amazing new developement in battery
## technology: www.altairnano.com/tech_products.html .

Altairnano is great. But also very very expensive, their battery energy density is lower than ordinary lithium ion (quite a lot lower) and AFAIK they can’t mass-produce their batteries (yet). Same thing with A123 batteries. Using these batteries Roadster would cost 2.5 times more than it does now (ESS alone would be about 1.5 times rest of the Roadster).

See blogs: www.teslamotors.com/blog2/?p=24 and www.teslamotors.com/blog2/?p=39

Tesla is keeping eye on these technologies, but they aren’t yet mature enough to be used in Roadster. Batteries are developing very very fast, so in the next few years Tesla might be using entirely different type of batteries in their ESS. Maybe even Altairnano.

Have you ever considered onboard power generation. Some years ago I came across an engine utilizing heated freon as it’s power source. The engine was called “The Chapman Rotary engine.” As I recall, it was a high torque, low RPM motor and was scalable, up and down in size and power. Chapman intended to use it as a primary automobile power source, but had difficulties with the transmission. He also utilized it as part of a home electric generating system. It is the electric generating aspect that got me thinking. Could a smaller version of the Chapman engine and it’s heat source be installed in a sedan sized vehicle or bigger, in place of most of an average size fuel tank. Ethenol or natural gas would be ideal fuel sources and the heat could be stored in molten salt. The heat source would only turn on when the temperature of the molten salt dropped to a certain level.

An onboard system like this could potentially move a vehicle like yours from a limited range vehicle to a vehicle with almost unlimited range. What are your thoughts on this.

Hmmm… Just found scientific source for new battery techs. There are few very very interesting things going on.

For example safe Lithium-ion polymer batteries with 520Wh/L energy density, moderately high cycle life (82% charge capacity after 500 cycles) tested by punched nail through at 45 degree celcius and overcharged without any indication of thermal runaway effects.

Or lithium ion with sulphur composite that has 246Wh/kg energy density. Using this tech Teslas ~400kg ESS (actual batteries) would be nearly 100kWh. (theoretical energy density using sulphur is 2.6kWh/kg. Woohoo!! How about 5000mile range?? or tenth of the size of current ESS and still getting about 500mile range? Unfortunately still far in future because other bad characteristics of sulphur in batteries)

Or almost zero capacity drop batteries with over thousand cycles (but with only 200+ Wh/L energy density) These would be nice as buffers for higher energy density ESS (capturing regenerative brake energy and store it).

etc.

These can be found in Journal of Power Sources (www.sciencedirect.com/science/journal/03787753), but that might require university access to be read.

Nothin brainy to add coz im just a joe bloggs mr average type of guy from manchester england, i just wanted to say that from everything i have read on the internet and in magazines that i think the tesla roadster is a fabulous piece of kit… truly brilliant in every way!!! Its a magnificent piece of design and engineering, never in my entire car-loving life have i aspired to a single car like i do the Tesla Roadster. The whole worlds gonna want one!!! I really really hope its made available in the UK, it would be a massive hit here guaranteed what with fuel costs being so stupidly high and green taxes and so on. Big up yourselves, everyone involved deserves huge respect.

# Timo wrote on November 28th, 2007 at 3:46 am
## 230 miles from North Lake Tahoe to San Carlos with two occupants plus luggage
## 227 miles of highway cruising on the I-5 freeway, south of Stockton
# I was wondering what kind of speed limits do you encounter between Lake Tahoe and San Carlos? Or in I-5 freeway?

Lake Tahoe to San Carlos would be mostly downhill (high altitude to sea level) so isn’t exactly a worse case. Traffic could vary a lot depending on time of day, & day of week. Overall average might range between 45MPH and 65MPH.
(You have to go through various urban areas such as through Sacramento, around Oakland, etc. which can lead to slow downs and stop/go traffic at times).

I5 south of Stockton can provide very long, flat, max speed limit opportunities for long distances. This is a common long haul truck route. You could easily average 70MPH most times and might even be able to get away with 80MPH (although not legally).

I wrote:

## Also another article that has lithium–carbon monofluoride battery with 360 Wh/kg
## and 700 Wh/dm energy densities, and that article is already two years old.

## With that Tesla ESS would be 147kg weight and 75 liter in size. That’s about size of
## a large gas tank and twice the weight when full. AND they say that “The prototype
## batteries and cells described in this paper are still not optimised, so further improvements
## in energy density of up to 20–30% are projected.” That would make 468Wh/kg and 910Wh/l.

Just to put scale to this highly probable improvement (it has been demonstrated as a battery, not just calculated in some insulated lab environment) lets change that 468Wh/kg in Tesla ESS size.

If we assume that actual batteries weight about 400kg leaving 50kg to casing and safety features that 468Wh/kg translates to approx 3.5 times more energy in same weight. (I have no info about Tesla ESS dimensions). Result is 187kWh ESS. That would give it 3.5*245mile=857.5 mile or 1372 km range. If that is not enough for everyone, I don’t know what is. 1372km at 80km/h average speed means >17 hours drive. I bet there aren’t many that would even want to drive any longer even if they could. With that kind of range nobody would need charging stations.

Tesla: These batteries and their technology was apparently developed by QinetiQ: www.qinetiq.com/home/commercial/energy/portable_power.html.

If I were you I would be contacting them to learn more about this, and if this lab-prototype battery was developed any further. If you could get them as your battery supplier and if they can mass-produce (or you can, with their tech) with reasonable price you could get battery techs way ahead of any of your competition.

Ebbeh? urgh. Just found carbon monofluoride battery article that says that 642Wh/kg was reached and _750_ Wh/kg is possible (predicted). That’s 1.5 times better than the one above. Halibut. I must stop reading these articles, they show so much improvements that I haven’t even dreamed about them. You just can’t get any other power source that gets even close to these.

# Rob W wrote on December 5th, 2007 at 12:32 am

## Tesla needs to create a cost-effective model that costs around $20,000.00

Wait for it. First they need to make that 50-60k$ family sedan first.

For out of curiosity I contacted QinetiQ. Unfortunately that 650Wh/kg battery was nonchargeable, so it was unusable in EV:s. But they said that they have developed a new battery that is one third the price for same range and weights half of current batteries just for hybrids and EV:s. Parsing that I got double-range 2/3 price ESS. Unfortunately that info wasn’t very specific, so I can’t make more guesses of what it could do.

But for those figures I get ~450mile range 13k$-20k$ ESS for Whitestar. That leaves 30k$ (worst)-37k$ (best) for car itself for that 50k$ car.

13000$ is about 55000 miles and it has paid itself back. Assuming gas price doesn’t go up.

Halve the range (to Roadster figures) and ESS costs 6500$. That makes 20k$ car possible, though 30k$ is acceptable for cheapest model.

Alexmcfire: I don’t think LED tail lights have a significant impact on electricity usage, though they do have the safety advantage of turning on and off almost instantly (incandescent bulbs take a moment to warm up / cool down), and they’ll probably never burn out.

Well, guyz — you’re going to have to do some tough trade-offs soon. Would you prefer a range of, say, 800 miles with 1/3 the battery weight, or, say, 1100 miles with half the battery weight, or, say, 2300 miles with the same battery weight?

What’s happened, and I’m sure you’re all over this like white on rice, is that Stanford has revised the design of the lithium-ion battery. ( news-service.stanford.edu/news/2008/january9/nanowire-010908.html ) Using silicon nanowire tech, it has multiplied charge capacity by 10. That’s “TEN”, 10, 5×2, √100, an order of magnitude. So, how y’all gonna divide that up?

:)

Tesla has a lot of engineers that came from Stanford.

Being a company based around Li-Ion battery technology, it wouldn’t surprise me if they knew about this work before it hit the press.

The real questions are: how close is this technology to being production ready? How quickly can they make them? How much will they cost? Who will own any related patents?

I still want to know who built the transmissions that failed in Tesla’s tests or more accurately fell apart. Why does the 3 tZeros that Alan Coucini built still operate with over 300,000 combined miles on them. Can’t he build a good transmission for Tesla?

Dave

##David Isaacs wrote on December 27th, 2007 at 1:56 pm
##I still want to know who built the transmissions that failed in Tesla’s tests or more accurately fell apart. Why does the 3 ##tZeros that Alan Coucini built still operate with over 300,000 combined miles on them. Can’t he build a good transmission ##for Tesla?

I might be wrong but I think I heard that the TZero was a single-gear car so it wouldn’t have the same problems. Like you I’m curious as to who the two failed transmission suppliers were and I’m sure that word will eventually get out about this. With so many cars now having paddle-shift gears that operate faultlessly as far as I know it is hard to understand why it has been so difficult to produce a reliable transmission for this car. I can only assume it’s something to do with the very high revs compared with other road cars but this parameter was obviously well-known right from the start. Many motorbikes have very high revving engines but I would guess that the only ones going all the way to 13,000 would be racing engines, and they don’t have to have the same reliability and durability as a road car requires. Maybe that’s it. Nobody else builds a road going vehicle that is expected to offer reliability and durability and also revs to 13,000 rpm. This makes it uncharted territory for transmission suppliers and maybe they underestimated the difficulty of meeting the brief.

For the transmission issue, have you looked into fallbrook technologies nuvinci transmission? it is a game changing idea. Lightweight, efficient and scalable to any application. Beautiful!
let me know if it helps. i left a message with jb to. there are also a couple battery/capacitor companies too that may be worth checking into. im sure you guys know most if not all of this but i also know that your incredibly busy so thought i would pass this info just in case.

OK, I’ll byte.
With a 10x battery density, all other things equal, here’s what I’d do: reduce the battery size to 1/3rd. With the saved volume add a supercapacitor bank that compensates for the reduced power output of the battery (unless that’s increased by 10x as well) and helps in regenerative braking.
Then remove the gearbox and the differential. With the saved weight and space add a second motor and put each motor coupled directly (through some simple reduction gear) to a rear wheel, with the same gear ratio as current design high gear.

End result: a vehicle that’s lighter and mechanically simpler. More acceleration (probably under 3.5 sec, as a result of significant weight reduction and same low end torque, by compensating the lack of a low gear with twice the power), is more efficient (fewer transmission losses), is more reliable (no gearbox or differential), has much better traction control (independent power to each wheel) and is more efficient (through better regenerative braking thanks to the supercapacitor). And still has over 3x the range (thanks to the 3x battery capacity and the regenerative braking efficiency gain).
Beat that.

Greetings,

Have you considered integrating a real FAST charging system?
One solution is the uncommonly stable lithium chemistry and high-surface-area nanopatterned electrodes by Altair Nanotechnologies’ lithium-ion batteries for electric vehicles or, a lithium titanate cell made by same folks, the Altair Nanotechnologies based in Reno, Nevada?
Charging a lithium battery generally means shifting lithium ions from a lithium metal oxide cathode into a graphite anode. Do that with too much force and lithium ions form a layer of highly energetic (and flammable) lithium metal on the graphite cathode. Altair Nano’s battery replaces the graphite with a itanium oxide anode that is much less susceptible to such plating, so the battery can be charged rapidly at very high power.
Please refer to: “Lithium Batteries Take to the Road,” IEEE Spectrum, September 2007″
Have you also considered increasing the present 220 miles range to at least 400 miles?
I believe with new smaller batteries with less weight by Altair Nanotechnologies, more batteries can be placed in in the same dedicated real estate
therefore higher range would result.

in a crash test, for example, at 60 kmh, frontal crash, the front of the vehicle will be smashed up i supposed. Would the portion at the driver’s seat be in good condition ? would the doors be dislodged from the car body ? i mean, would the driver be safe ?

# jong kouren wrote on January 10th, 2008 at 5:00 am

## in a crash test, for example, at 60 kmh, frontal crash, the front of the vehicle will be
## smashed up i supposed. Would the portion at the driver’s seat be in good condition ?
## would the doors be dislodged from the car body ? i mean, would the driver be safe ?

Tesla Roadster has passed crash testing. It is just as safe as any other car of its size. Obviously if you drive at 100mph into front of the 18-wheeler going 50mph to the opposite direction you (and Roadster) end up in quite a bad condition. I think it would be challenge to find all parts and determine if this is part of you or the vehicle.

# Alex Safari wrote on January 10th, 2008 at 11:58 am

## There is another battery technique that I like to share the info with you. Perhaps there are
## some useful info for TESLA? EEStor, based in Cedar Park, TX, is developing a ceramic
## battery chemistry that could provide 10 times the energy density of lead acid batteries at
## 1/10th the weight and volume. As envisioned, EESUs will be a fully “green” technology that
## will be half the price per stored watt-hour than traditional battery technologies. You did
## mention SILICON versus GRAPHITE, how abouit CERAMIC?

EEStor has been this far a waporware company. If they can produce their promised product it will still lose to advanced silicon nanowire by quite a bit. EEStor EESUs supercapasitor has about 1.5 - 2 times the energy density (if it is real) of _current_ lithium ion, but there is already new development that makes lithium ion much better. That silicon nanowire is 10+ times better than current lithium ion, so it is at least five times better than EESUs for energy density. What is good in EEStor supercapasitor is that it is capasitor giving enormous power density and very good stability for repeated cycling making it very good as buffer for regenerative breaking and stuff like that.

That is assuming that it isn’t entirely waporware.

I’m sure you’ve already considered this (although it hasn’t been mentioned here), but Lithium-polymer batteries may offer a better performance curve/duration of service than the latest available Lithium-Ion batteries. I recently made the change from Lithium-Ion to Lithium-Polymer in my cell phone (not a very good comparison, I know), and have noticed the following differences:

Li-poly provides a greater capacity (mah capacity) per ounce/volume than does Li-Ion
Li-poly batteries accept a charge MUCH faster than their Li-Ion counterparts. With my Li-poly battery, I can fully charge my cell phone in about 15 mintues, instead of the 2+ hours it would take with Li-Ion.
Li-poly batteries are cheaper to produce than Li-Ion, and give similar benefits (no memory effect, long duration of service).

Li-poly batteries have been in use by the model aircraft industry for a few years now, due to their superior weight/performance characteristics over Li-Ion batteries.

If you haven’t tried Li-poly batteries (or done any performance analysis on them), they are certainly worth looking into. You may find that for the same weight/volume, Li-poly batteries may offer an extended driving distance, and shorter recharge time (both would be good for an electric-only car such as the Tesla roadster).

PSW.

Might the recent discovery at Stanford Univerisy with nano technology improving the capacity of Lithium Ion batteries by 10x also improve the range of a Tesla motor car?

WHEN IS THE NEXT TOUCH BLOG POST COMING UP?. ITS BEEN QUITE A FEW MONTHS SINCE THE LAST ONE.

The revised EPA estimates do not indicate a difference in the kWh/100mi figure. Can I correctly assume that the kWh/100mi figure increased with the revision? That is, the combined cycle test reported here used 2.45*31 = 75.95 kWh. For the new numbers, if the kWh used remains the same, then the kWh/100mi goes up to 75.95/2.21 = 34.3 kWh/100 mi. Is that correct, or does the kWh/100mi figure remain the same even though the range was reduced? Thanks!

Interestingly, the Idaho laboratory link given by Andrew Simpson shows the EV-1 at 248 wh/ mile, or 24.8 kwh/100 miles, making it supposedly 6.2 kwh/100 miles more efficient than the Tesla. The Tesla seems to have more than adequate efficiency, but that was 1999. So it shows how BIG a mistake it was for General Motors to kill the electric car, and pursue silly hydrogren, silly ethanol, and silly e-85 vehicles, where the biggest practical effect is in food prices at the market.

GM still hasn’t a rational policy: Supposedly one of the versions of the VOLT is going to be Hydrogen Powered, and only cost a few million bucks a piece. Customers need that version like a hole in the head. So now I’ve got to go to a chemical factory for fuel? hehe.

About battery replacement. It won’t be as long as 100,000 miles unless you really drive a lot.

Li-Ion batteries are pretty well knackered at five years or maybe as little as two.

Going on 4Wh/US$ the pack will cost approximately $13k.

So based on 100,000 miles that’s 13cents a mile. Sorry but my motorbike is cheaper, faster and goes about the same distance on a fill.

You’ll also need more than a normal leccy supply to charge one of these overnight. Your supplier will charge you thousands for that and in any case the grid just won’t cope. In fact here in Cambridge UK some regular offices are having trouble getting a supply at the moment !

Jon
an Automotive Electronics Engineer

I read the test drives courses for the car. I did not see the 395 listed. I expect alot of your So cal customers will take this route which has a very vigorous grade ( THe Sherwin Grade) which climbs several thousand feet between Bishop and Mammoth Lakes within a 20 minute drive. This would be a good test.

Wondering if Telsa should go with cheaper battery technology and have exchangable batteries. One battery could charge at home and one in the vehicle. Therefore one battery is always fully charged. I can’t see consumers replacing $20000 batteries every five years, the total cost of ownership will be too high. The car could come without a battery and “Energy” companies could sell/exchange batteries to an end user. This gets around the range problem and the cost of the battery is absorbed by the Energy provider. Food for thought.