REPORT: Tesla Model S could have 95 kWh battery pack
Tesla Model S in motion - Click above for high-res image gallery
Let's compare: the battery pack in a Tesla Roadster today is 53 kWh. The pack in the Chevy Volt? 16 kWh. The Nissan LEAF? 24 kWh. The Hymotion/A123 kit to make your Prius a plug in car uses a 5 kWh battery. Now, how big might the battery in the highest-range Tesla Model S be?
When Tesla revealed the Model S back in March, they said that the car would be available in three flavors: versions that had ranges of 160, 230 and 300 miles. The standard pack, it was revealed, would be 42 kWh, with "70 kWh and greater battery storage systems optional." Jim Motavalli has now gotten Tesla's chief technical officer, J.B. Straubel, to give a first public estimate of how big the 300-mile pack will be: 85 to 95 kWh.
Motavalli easily found plenty of skeptics willing to criticize a pack this big: it'll be too expensive, take too long to recharge and weigh too much, they said. Straubel's response: we have three years to figure this out, and battery technology advances quickly. Sure, but still, 95 kWh? Yikes.
Gallery: Tesla Model S in motion
[Source: New York Times]
Reader Comments (Page 1 of 3)
Stan Peterson 2:27PM (8/25/2009)
Drive it one day and recharge for three days. It fits pefectly for the toy in the mega-millionaires garage . Which after all, is the market for a car produced in a product run of 200-300 cars over five years, just like the Tesla-Lotus roadster. Duh...
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paulwesterberg 2:42PM (8/25/2009)
You must have missed the memo about tesla's quick charging technology. It might still take 8 hours to charge, but I usually like to get some rest after driving 300 miles.
On daily drives of 40 miles charging time would hardly be an issue. Personally I think that 160 miles is the sweet spot, then use a small trailer generator as a ranged extender on longer trips. Then you only need to haul the range extender when you need it.
Throwback 2:42PM (8/25/2009)
I'm sure Tesla will offer a fast charger for a sizable sum, so those willing to show how REALLY environmentally friendly they are can show off to their friends. It makes owning that G4 a little more palatable.
Marc-O 2:52PM (8/25/2009)
Yes, because only mega-millionaires buy $50,000 sedans.
Brad Brack 6:05PM (8/25/2009)
A 220V/30A dryer outlet (which even non millionaire-types have) can get you conservatively 6kWh per hour charge. If a 95kWh battery can do 300 miles, that means if you use the entire pack, that's 3 miles+ per kWh.
So, an 8-10 hour overnight stay would net you (again conservatively) 48-60kWh or 150-180 miles. So, as long as you don't go over 150 miles a day, you don't need to have a more powerful charger.
If you want to take a weekend trip you'd have to plan for it to be no further than 250 miles (assuming you want some of the 300 mile in reserve) without charging. Then, you can use the other days of the week to incrementally recharge.
It does get a bit more practical, but still probably not quite to the point where the masses would have this as their only vehicle.
Chris M 4:42PM (8/25/2009)
Stan, Tesla Motors has already delivered more than 600 Roadsters in just a years production run, and they've been increasing production. At half the price and with more room, the Model S should sell in much greater quantities.
Tesla plans 3 charging options for the Model S.
Standard home 240 volt charging should charge in a few hours, depending on how much charge the battery needs. Figure about 65 miles of range for each hour of charging.
High power 480 volt charging for "under an hour" charging in public "park and charge" lots. These will be designed for public and commercial fleet use, not likely to be used at home as homes don't normally have 480 volt wiring. .
Standard 120 volt outlets, mainly for minor "top offs" and emergency charging, as it could take a very long time to do a full charge that way. Figure about 6 miles of range for every hour of charging.
Tohe 8:14PM (8/25/2009)
I wish EV advocates would drop the range extender idea, it underplays the already satisfying and constantly improving range BEVs and it creates doubts in the public's mind. Think about it, who is willing to drive with a trailer around? not me, that is for sure.
Snoopy 2:35PM (8/25/2009)
There's something I don't get about this estimate.
If the Roadster pack is 53kWh and gets approximately 244 miles from a charge, then why would the S need a 85-95kWh pack to get 300?
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Mark Kiernan 2:41PM (8/25/2009)
Weight I assume the model S will weight considerable more than the roadster.
Eugene 2:44PM (8/25/2009)
probably cuz its heavier
paulwesterberg 2:48PM (8/25/2009)
More passengers, more cargo, and as the battery pack grows larger it weighs much more so there are diminishing returns.
The first 25kWh may get you a range of 150 miles, the next 25kWh gets you an additional range of 100 miles, the next 50kWh may only yield 50 more miles. The drivetrain is already very efficient, so aerodynamics, weight, and rolling resistance(in that order) determine how far you can travel.
Snoopy 3:15PM (8/25/2009)
Thanks guys.
Turbofrog 3:44PM (8/25/2009)
It seems to me, paul, that the exact opposite would be true; as you increase the size of the battery pack beyond it's initially necessary size, you would extend the range disproportionately more. The small pack still needs to haul around the passengers, chassis, drivetrain, and all the rest. The larger pack only needs to haul around its own weight increase, and the modest reinforcements necessary to accommodate that throughout the body.
It's not the way for ultimate efficiency because you are carrying additional weight, but for ultimate convenience you get more than you give up when you increase the pack size.
But yeah, 95 kWh is absolutely ridiculous. They should be able to get well over 300 miles with a pack like that.
Snoopy 3:53PM (8/25/2009)
I think the issue with the weight increase you're talking about, and likely what the guys were essentially saying, is that that extra weight, specifically, is still too much (at least with the current efficiency levels).
Jeremy 12:02PM (9/04/2009)
Range estimates are based on the EPA driving cycle (which includes city and highway) so, yes, weight will affect your mileage. However, weight has little effect if you're driving a constant speed... it only takes more energy to *accelerate* a heavier car. Keeping it going 65 mph is not really affected by weight, and many studies show a heavier car -- given identical aerodynamics to a lighter one -- will get better highway mileage because it's less affected by gusts of wind and brief changes in the road like tiny hills, roughness, etc (more momentum).
Considering the Tesla will generate electricity to charge the battery when you let off the gas, that extra mass would actually mean more charging, too (it wont slow down as fast under regenerative braking as a lighter car).
Based on the difference in battery capacity, that estimated range may very well be quite conservative. The Roadster does, in fact, get a legit 240+ miles on a full 53kw charge.
BlackbirdHighway 2:52PM (8/25/2009)
Cells are already available in the standard 18650 form factor that would boost the Roadster's pack up to 65KWH. That should boost range to 290 for that car.
The batteries are constantly improving. I'm looking forward to upgrading the pack in 5 to 7 years and getting 500 miles or more.
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Tim 2:53PM (8/25/2009)
"Straubel's response: we have three years to figure this out, and battery technology advances quickly."
Good, I hope they do figure it out. In the mean time, GMs Voltec drive train makes more sense since it's 40-mile range covers the daily trips for 82% of commuters with a pack that's 1/5 the size, weight and cost of the Tesla Model S.
A FIVE FOLD increase in battery pack size, weight and cost of the Tesla Model S is a LOT just to cover the other 18% of drivers who's daily commute exceeds 40 miles and they will STILL need fast-charging for long trips in excess of 300 miles.
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polo 3:38PM (8/25/2009)
"A FIVE FOLD increase in battery pack size, weight and cost of the Tesla Model S is a LOT just to cover the other 18% of drivers who's daily commute exceeds 40 miles"
Lets put things in perspective. You get a FIVE FOLD increase in range with no compromises in power, design, or capacity for only $15K more. The Model S is built and priced for luxury EV buyers. It would be attractive for someone who might by a BMW or Mercedes. Its not average car buyers...thats what the Model T is for.
jake 3:51PM (8/25/2009)
The base pack is 160 miles, so it already covers more than the 80% the Volt covers. 160 miles is probably 90+% of drivers.
Ideally we can move away from needing a "range extender" and Tesla is pushing us in that direction. The only reason we need range extenders today is because of battery cost and lack of fast recharging infrastructure. I see a range extender as a interim solution to the problem. It's definitely more practical for today, but I think we still need to push the technology forward so BEVs can eventually get as close as possible to gasoline cars today. Once we have a 300 mile pack, then the "range anxiety" issue frequently mentioned by skeptics of BEVs is greatly diminished (though in actual practicality, a 300 mile battery is probably overkill) and the next step is working on rapid recharging and reducing cost.
If you directly use the current 53kWh pack @ ~900lbs weight then a 85-95kWh pack would be 1450-1600lbs, which is too heavy for most vehicles. However, given the Roadster uses 2.4Ah cells, they still have room to move to higher density 3.0Ah cells which would bring the weight down to 1160-1280lbs. 3.6Ah seems to be the cutting edge, which will bring it down to 1000-1100lbs. So a 300 mile range Model S is certainly doable (though it'll be expensive). If they don't go the removable battery route, it's a good chance the battery pack will be used as part of the structure to reduce overall vehicle weight.
Tim 3:53PM (8/25/2009)
Well Polo,
I guess we'll just have to wait for 3 years to see where the Model S is priced and what kind of battery pack it comes with. 3 years is a LONG time when you consider how fast battery technology is progressing. In 3 years, the whole world can change.
The best laid plans of mice and men and yes, we do live in interesting times.