Battery Size

Battery Size

Here's how I think battery size will play out in the coming three years:

1. Model X will have an 85 kWh base battery, optional 100+ kWh. This will allow it to achieve range goals similar to the Model S.
2. Model E will have a 60 kWh battery, optional 85 kWh.
3. Model S base will become 85 kWh, with an optional 100+ battery.

Tesla intends a 200 mile range goal on the base Model E. 55 kWh would do it, I think they'll perk it up to a 60 since price will start to fall with upcoming honkafactory.

Brian H | 5 mars 2014

Nope. Base Model E battery already announced as 48kWh.

Iowa92x | 5 mars 2014

48 kWh won't provide 200 miles. If you are referring to the article that computed battery size based on reducing a 60 kWh by 20%, that was a guess on their part. Fuzzy math. I doubt Tesla even knows for sure the size until they wind up the design process.

Bubba2000 | 5 mars 2014

Fully populated, the MS battery pack probably could store 100+ KW-hr. Even with Superchargers deployed, the extra energy will help with hi speed driving, cold weather, etc. If AWD (550 HP!) is offered, energy consumption will go up.

Range and power sells! Most of the cars being ordered are the souped versions: 85P or 85P+. Tesla could charge an extra $7.5K and it would sell!

Timo | 5 mars 2014

@Iowa92x, 48 kWh should easily provide 200 miles. Roadster has 53kWh battery which gives 244 miles (old EPA) and Roadster has aerodynamics of smooth brick. Model E, not being much bigger in aerodynamics point of view and far more aerodynamic, should be able give about same.

@Brian H, I have missed that announcement. Link? Any official news about Model E is better than no news.

Brian H | 6 mars 2014

Brief comments by Elon in his Euro interviews. Note that the size of the ME is 20% less than the S60, and 48kWh is 20% less than 60kWh. I think there's a connection!

EQC | 6 mars 2014

As far as I know the "48 kWh" is only a third-party calculation based on Elon saying recently that the battery would be 20% smaller. However, he said that only while talking about cost reductions for Gen III (ie: not listing specs), and he didn't define the size metric he was using (mass, volume, energy capacity, etc.) Is there an official statement I don't know about where somebody at Tesla actually used a number?

Looking at the other EV's on the market (Leaf, Focus, Fit, BMW i3, upcoming Mercedes B-class EV), they all have batteries in the 20-30 kWh range, and NONE Of them even achieve 100 miles of rated range. The Leaf, for example, is a 24 kWh battery with an EPA range of just over 80 miles on a full charge (with a standard charge being less than that). Nissan did originally advertize a 100 mile range...which was probably a mistake, and only works if you're hypermiling in city traffic. I expect better than that from Tesla.

Granted, the other EV's on the market aren't very aerodynamic, but most are also compact cars (smaller front X-section) and are probably lighter than the Gen III will be. On a 2x bigger battery pack, can we really expect Gen III to get 2.5x the range of a LEAF?

While the Roadster got over 200 miles in the old EPA test with a 55 kWh battery, it was a very small car (ie: very small frontal area), which would have counteracted the poor drag coefficient some. New EPA tests are harsher, and a family car Gen III will be notably larger.

I hope that when Tesla says "200 miles range" they mean a practical value that doesn't require slow driving and a 100% charge to achieve.

grega | 6 mars 2014

Can someone te me why tesla dropped the 40kwh option from model S? Because it would seem a natural offer for a smaller car still, but is like to understand their reasoning.

A 150 mile range with battery swap to 300mile range would be interesting.

grega | 6 mars 2014

Darn screen keyboards. Sorry.
"Tell me" "I'd like to understand"

Iowa92x | 6 mars 2014

ECQ above has it right. Perhaps the Model E battery will be a 20% reduction in mass, but it won't be a 20% reduction in kWh compared to a Model S 60. 48 kWh for 200 miles doesn't pass the common sense test. The E will use a 60 kWh pack. Elon says new factory should cut battery cost by 30%.

Let me break it down a different way. An 85 kWh pack has 80,000 watts of usable range. If you average 325 watts per mile, that is 246 miles of range. It's reasonable to think the Model E will burn at least 275 watts per mile. 275 watts per mile times 200 miles is 55,000 watts. Add a 5 kWh buffer so not tapping out the pack and you got a 60 kWh battery for the E.

Iowa92x | 6 mars 2014

P.S. A 48kwh pack has 45 kWh of usable range. Model E would need to use only 225 watts per mile to squeeze out 200 miles. 225 watts per mile is not realistic. Physics.

Brian H | 6 mars 2014

No, Elon said "48 kWh" in so many words. Makes sense that it matches the mass reduction, though.

Timo | 6 mars 2014

225W /mile is realistic. It just needs good aerodynamics and low weight.

Model S is heavy. Battery is only about 15% of the car weight. It would be heavy even with battery removed. I think it is a bit overengineered for safety.

Even with steel frame I think Model E can be quite a bit lighter. 48kWh battery (as pure batteries, not pack) is only about 200kg. Probably less with Tesla batteries. That makes possible for car to be really lightweight. Especially if they add some engineering magic to pack to make it even lighter than Model S pack is relatively speaking.

That said, I expect 48kWh Model E to be the absolute low end option and the actual high-selling one to have quite a bit bigger battery.

In fact I will be a bit disappointed if the car doesn't have at least 200 mile real life range with cheapest options possible. I fear that they do in reality choose lower range in order to get that more or less promised $35k price tag.

Bubba2000 | 6 mars 2014

Model S weight is 4,647 lbs. Take out 1,000 for the battery pack and it is still 3,647 lbs. That heavy for an Al car. The car is heavily reinforced with Boron Steel structures. Even the Al structures, castings are massive. No wonder it came at the top in safety.

Tesla could lighten up some by going with a stronger alloy of steel, optimizing the structural design. May be take out 500 lbs. I would prefer safety and pay for extra battery energy storage. I have seen in my line of work, too many cars like the Honda Civic and even the Accord that are design for fuel efficiency, get completely crushed in a MVA, especially against heavier vehicle, with dead people and severely wounded. Sure Tesla could use Titanium Alloys, but they are very expensive to implement.

I suspect that with Model E, Tesla will use weight saving techniques use with aircraft, while maintaining safety and structural integrity. A lighter car will need less reinforcement.

I own an 85P loaded, and I have seen anything more responsive. I have a Porsche and it feels slow especially especially the 911 from the get go. Once I got it on the track, at above 100 mph, the 911 is a real bad boy. I have not tried the later Porsche 911 Turbo S, but that got to be a speed demon at speeds about 60 mph with both turbos spooling. With time, I think Model S AWD 600 HP and a 150 KW-hr will beat the 911 Turbo S.

Timo | 6 mars 2014

One advantage BEV has over ICE is, surprise, lack of ICE. They can optimize structure in crumple zones for impacts without caring about drivetrain jumping in lap of the driver. That has to mean less heavy structures while keeping the safety.

MEGEN | 7 mars 2014

Every thing OK but battery is weak point that should be improve / learn self running no more charging station please see >>>

Bubba2000 | 7 mars 2014

Thanks for the youtube link. It explains the reason that Tesla's battery pack outperforms all others. The extra "sauce" that Tesla adds to the Li-ion makes these NCA batteries have a long life and sustained energy density. Obviously, Panasonic plays a big part here. The Tesla has significant focussed research and testing. Over time, they will improve the battery performance.

Temperature control, charging and discharging control make big difference in the performance and life of the battery. Nobody comes close. Another lesson I learnt is that I should avoid max charging my 85P. Just charge it to 80% and preferably at no more than 20 Amps/240. Charge the car every night. With the kind of driving that I do, I may need to max charge may be 4-6 times/year. When the Superchargers get installed on my routes, just charge 50% at the most.

holidayday | 7 mars 2014

Brian says "Elon said "48 kWh" in so many words."
Do you have a link to that quote?

If you are using the percent off of 60 KW, then I think that's the wrong way of looking at it. I think he meant the percent off the physical size of the battery, not the capacity.

Unless you provide a link to the actual word "48" from Elon, then I'm skeptical that this is what he meant.

Tesla is improving energy density of the batteries as well as reliability, so I expect the number to be larger than "48" for the standard battery.

But hey, if Tesla can make the 48 go 200 miles, it just might be the answer. Either way, all of us (even Elon) could be wrong! We will see when they actually announce the real numbers in 3 - 5 years.

Joshua Burstyn | 7 mars 2014

It's fine if the 48kW battery is the base. I'd like to buy a large pack though - one with more range than even the 85kW Model S has now.

Bubba2000 | 7 mars 2014
Bubba2000 | 7 mars 2014

The link that MEGEN provides does shed light on the advantages that Tesla has over competition. Tesla does have IPRs and trade secrets that will are barriers to entry for the competition:
1. The NCA positive electrodes in combination with the electrolyte chemistry result in the batteries retaining most of their capacity over multiple cycles and life of the automobile. Competition does not come close.
2 Battery management in combination with temperature control algorithms provide for optimum charging and discharging characteristics. Use of supercharger.
3. Tesla in conjunction with Panasonic has extensive research, particularly in testing the newer chemistries, electrodes, separators, etc. Lot of proprietary data.

The focus has been on battery tech advances, but Tesla may already be there. I think the company could over time reduce the weight of the Model S by 500 lbs using lighter but stronger alloys of Al, and even Steel. Improved structural design could reduce weight too. Use economies of scale to cut costs of both the skater board and the glider. Right now my P85 at 4,647 lbs, feels like an armored Großer 770, but I do like the safety it offers.

Iowa92x | 7 mars 2014

Weight matters less to economy (watts per mile) when traveling at 70 mpg on flat ground. It's all about air resistance. The E will have only slightly improved coefficient of drag compared to the S. Weight wise it will be 600 lbs lighter. Weight does matter in stop and go traffic and hills.

Call me out in 3 yrs if you want, the Model E will have a base 60 kWh pack.

Brian H | 7 mars 2014

A recent interview, don't remember which. Your skepticism bothers me not at all.

"and I have seen anything more responsive." have not seen ??

Timo | 8 mars 2014

Rolling resistance is dominating loss up to about 50mph for Model S. It matters. Air resistance will also be smaller for smaller car.

I said a bit earlier that Roadster gets 244 (old EPA) miles from 53kWh battery, and it has coefficient of drag of smooth brick. Frontal area of Roadster is not that much bigger than Model E frontal area will be (it's nearly as wide as Model S, but lower).

Difference between range for Model S and Roadster comes from weight.

Iowa92x | 8 mars 2014

Roadster hitting 244 miles under the old EPA is what, 205 miles under new EPA testing? Old testing method was a joke.

Roadster rides on the Lotus Elise chassis, one of the smallest, lightest sports cars in the world. The roadster is 2,700 pounds and a tiny two seater. It still needs 53 kWh to go a touch over 200 miles. That seems like fairly strong support that a 3,800+ lb four door largish Model E will need a 60 battery for 200 miles.

Timo | 8 mars 2014

It still has frontal area that isn't much smaller than Model S which was kinda the point. For aerodynamics Model E will be far better than Roadster. I also don't think Model E base model will weigh 3800 lbs. More like 3300 lbs (1500kg) which is about what BMW 3 series and Audi A4 sedan weights.

hm. noticed typo in my previous post. Obviously "Roadster is not that much smaller than Model E frontal area".

Bubba2000 | 8 mars 2014

Tesla has room to improve based on what I see with the Model S, both in terms of weight and aerodynamics. Model S is build with heavily reinforced Boron Steel... large members. With a lighter car, stronger alloys, may be Tesla could cut down some of the weight. All kinds of materials are available starting from Carbon Fiber Plastics, honeycomb structures, metal alloys, etc. Cost is an issue, of course. Improved bearings of the moving parts.

Hi pressure skinny tires, with aerodynamic wheels, improved airflow under the car especially around the tire wells? Eliminate side mirrors and add cameras like with X, without sticking them out? Improved flush windshield wipers?

The wiring, power switches, inverter efficiency, etc could be improved.

Iowa92x | 8 mars 2014

Timo, looks like you are correct that the Model E likely will have a much improved coefficient of drag compared to the Roadster. The Roadster is .35, Model S is .24. That's good news.

The Roadster's drag issue is partially due to being a convertible. Don't know if that .35 is tested with the top up or down, top down drains the gas/electricity.

carlgo | 8 mars 2014

If the E is to be affordable Tesla won't be able to charge the up-front Supercharger fee and the battery will have less range as well.

This is pretty much going to force Tesla into enabling a vast charging network, hopefully for profit.

Tesla will make more money from recharging than from making cars.

Brian H | 8 mars 2014

Nonsense. The whole cost of the SC network can be written off as a (very minor) marketing expense.

jstack6 | 8 mars 2014

Grega in answer to your question= grega | March 6, 2014 new

Can someone te me why tesla dropped the 40kwh option from model S? Because it would seem a natural offer for a smaller car still, but is like to understand their reasoning.

Sales were all for 60 and 85. Lack of demand led then to drop the 40kwh pack.

*The Gen 3 will be smaller and lighter so 48KW could let it reach 200 miles on a charge similar to the model S going 300. *

Timo | 8 mars 2014

200 same way as Model S 300 would not be real life or EPA range. Unfortunately that's what I think it will be.

I think Model E reaching 200 miles in real life with just 48kWh is possible, but not likely. Requires a bit too many compromises/expensive materials if you want to keep price down.

rotor.vol | 10 mars 2014

On page three of the following document
it is said that 2020 Gigafactory Pack Output is going to be 50 GWh/yr, which is considering projected vehicle volume of cars in 2020 of 500K gives us an average battery pack size of 100KWh.

Also assuming that the majority of produced cars would be Model E we can expect Tesla to state maximum range of Model E to be approximately 400mi and the effective range to be 350mi.

In my computations I use the fact that 100KWh is approximately ~18% greater than 85KWh pack available for Model S, and the maximum range for model S is 300 with effective range of 265.
I also assume that Model E would be approximately 10% more efficient than model S due to smaller size.

ghillair | 11 mars 2014

Your calc does not consider that part of the gigafactory output will be going to grid storage and to other car manufacturers.

rotor.vol | 12 mars 2014

ghillair -> you are correct on this I did not think about that when I did the estimates.