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## Tesla Model E Will Be 20% Smaller, Have 48 kWh Battery

## Tesla Model E Will Be 20% Smaller, Have 48 kWh Battery

Submitted by sagebrushnw on 03. März 2014

Does this info give any "new" news about the GENIII Tesla?

http://gas2.org/2014/03/03/tesla-model-e-will-20-smaller-48-kwh-battery/

RedShift| 03. März 20144000 lbs. not bad. Could be better.

AndreyATC| 03. März 2014If the battery weight difference alone is 200lb between 60 and 85, it would put MS with 48kw into 4200 territory already.

But E is 20% smaller and that's a lot for a car

I can easily see it at 3800 or so

Brian H| 03. März 2014Gains some weight back in the steel body.

RedShift| 04. März 2014Brian,

Where did you read that it was to be steel?

I tried looking for steel on that page and found none.

AmpedRealtor| 04. März 2014If the Gen 3 is going to be made of steel, I'm not sure why Tesla would invest so much money to own its own aluminum stamping machines - which are used to create the auto body, panels and parts. Those machines can crank out far more than just Model S and Model X pieces.

shop| 04. März 2014In that clip, Elon never said anything about battery power. He just said the pack would be 20% smaller - which could mean physical size. In three years, I would expect Tesla's batteries to have higher power density. So the 48 KWH figure is just made up by the article writer, don't take it as gospel.

What Elon did confirm was 20% lighter/smaller car, 200 mile range, and $35K price point.

RedShift| 04. März 2014If it's 20% lighter than the heaviest S it will be around 3700 lbs.

I'd say anywhere between 3700-3900 lbs for the E.

I am sure they will stick with the rear engine, rear drive (RR) platform and Aluminum space frame and most panels since their expertise is with those ingredients.

I think this will be a genuine 3 series killer. :-]

EQC| 04. März 2014@shop: Very much agreed. A 48 kWh battery would actually be pretty worrisome. While Nissan made the mistake of originally advertising their EV range as "100 miles," the Leaf's 24 kWh is really only good for about 70-80 miles on a full charge (unless you're planning to hypermile in the city). If you double that range for a 48 kWh battery, your practical limit is much less than 200 miles.

Anybody want to take any guesses about how Tesla defines 200 miles of practical range for the Gen III? 100% charge and ideal conditions, or 90% charge and "rated" conditions? Some other metric?

I also wonder what they mean by "20% smaller" for the car. Is that in approximate volume? Approximate weight? Obviously the height of the car can't decrease much, so what fractions do you think they'll remove from the length and width?

Pungoteague_Dave| 04. März 2014@amped - TM's stamping machines are repurposed from the NUMMI plant and originally did stamp steel. I read that they had to be reconfigured for aluminum, but it might be possible to use them for both metals.

Given that Ford is finding a way to make $24,000 full size pickup trucks out of aluminum, it might become increasingly feasible given economies of scale, for TM to reconsider and use the lighter metal on the Gen III too. Mainstream carbon fiber and aluminum body construction are becoming ubiquitous - it would be a shame to see TM step back if they can go lighter and still control costs.

AtlantaCourier| 04. März 2014One thing is being overlooked here: Aerodynamic Drag.

"Range," as we understand it, and by how Tesla and the EPA determine it, means "how far you can drive at speeds between 55 and 75 mph."

When Tesla said the range of the Model S was 300 miles, they meant at 55 MPH. When the EPA rated it at 265 miles, they were using their five-cycle test, which includes speeds up to 80 MPH among other things.

So, when we talk about range, we almost always mean the range at highway speeds.

Aerodynamics is an important factor when determining range, and it does not scale linearly with increases (or reductions) in vehicle size. It scales exponentially.

In other words, you cannot say that a 20% smaller vehicle will require a 20% smaller battery to maintain a 200 mile range.

Why?

Because if a car's size is reduced by 20% in all dimensions, then the frontal cross-section is, of course, 20% smaller.

But the aerodynamic drag is 40% less

This means that the battery can be reduced in size by more than 20% and by as much as 40% while still being able to achieve the same range.

Therefore, if the frontal cross-section of the Model E is 20% smaller than a 60 kWh, 200-mile range Model S, then a 48 kWh battery (straight 20% reduction) will enable well over 200-miles in range - probably closer to 265.

My numbers show that the battery could be as small as 38 kWh while still enabling a 200 mile range, and that a 51 kWh battery will enable a 265 mile range.

Of course, a "20% reduction in size" does not necessarily mean the frontal cross-section will reduce at all But a significant reduction is still very likely given that its Tesla we are talking about.

Mark K| 04. März 2014Very astute observations by AtlantaCourier. The concurrent changes in Gen III have compound benefits.

Chassis mass will drop as the cube of linear measure. It will stay aluminum because mass is so important.

Aerodynamics is huge for highway range. Look for the frontal cross section to drop by at least 20%, which will yield gains squared vs. velocity.

The battery will be smaller by leveraging the compound of two effects:

1. Less capacity due to reduced drag and mass (much of which is ironically less battery)

2. 35% improvement in gravimetric energy density due to improved cell chemistry.

My guess:

Entry level - 45kWh / 3500 pounds.

At $35K, think of it as 10 bucks a pound. That's an amazing value for such advanced tech.

E is for economics, which is the killer performance metric for the Model E.

The cars are already better, the last frontier is price.

TeslaTap.com| 04. März 2014@Pungoteague_Dave - actually the Schuler hydraulic press line came from Detroit. It stamps all the large sheet made parts (doors, hood, fenders, hatch, etc.). The press is the 6th largest in the world, and is 7 stories tall! There are a number of small presses used to make small parts, and these may have been bought from NUMMI.

I don't know if the Schuler press line will do steel or not, but the major reason for going with aluminum is the weight savings. If they stay with aluminum it would be one of the lowest cost aluminum bodied car made!

EQC| 04. März 2014@AtlantaCourrier, MarkK:

I think you guys are somewhat mistaken.

The force of Drag = 0.5*Cd*A*ro*V^2.

In words: Drag = one half multiplied by the drag coefficient multiplied by frontal area multiplied by air density multiplied by the square of velocity.

Drag scales linearly with frontal area (A). In other words, if you decrease the frontal area by 20%, the drag force only drops by 20% -- not 40%.

The Drag force scales quadratically (ie: V^2) with velocity.

Additionally, the car is pushing against more than drag -- there is rolling resistance (ie: friction internally and with the road) as well.

Rolling resistance scales linearly with both mass and velocity.

So, if you shrink BOTH the mass and the frontal area by 20%, you should get a 20% increase in range at any given speed. Drag is more important at high speeds, but both still matter.

Further: the Gen III isn't likely to have a 20% smaller frontal area anyway. The frontal area is basically the width of the car multiplied by its height. The Model S is already fairly low...so the Gen III will probably be about the same height. That leaves only the width as a way to decrease the frontal area. With mirrors folded, the Model S is 77 inches wide. Decrease that by 20% and you're down to a width of 61 inches, which would not likely be the Gen III target.

Brian H| 04. März 2014Elon mentioned the steel body in an interview, mostly intended to keep costs in the target bracket.

jkn| 04. März 2014AtlantaCourier,

Since people must fit inside of the car, frontal cross-section cannot be much smaller. Perhaps 10 % narrower. Lower car would be unpractical, unless battery is moved. It will probably be 20 % smaller by weight. 10 % comes from width. This reduces air resistance by 10 % so battery can be 10 % smaller for same range. Battery energy density will be higher. So smaller battery will give same capacity. This will give another 10 %. Range will be same, so supercharges can be used.

Mark K| 04. März 2014@EQC - totally correct.

My sentence tried (unsuccessfully) to make the point that drag goes as the square of velocity.

I do think the frontal area will be 20% smaller. Model S is very wide, and 3 series BMW is quite a bit smaller.

@brian - can you post a link and time to the video interview where Elon discusses steel?

Model S also has internal reinforcements that are steel, maybe the ratio will be different with the Model E.

AmpedRealtor| 04. März 2014Has the Model S set the bar too high for Model E?

I ask this question sincerely and with the best of intentions. Model S has given us so many firsts, class leading performance, one glorious review after another, and it has won award after award. Will Gen 3 be met with similar fanfare, or will it be compared to its bigger brother, the Model S, and viewed as a compromise?

One of the reasons Model S is successful is due to the tons of media praise for the car. If Gen 3 arrives with a steel frame and sub 300 mile range, will the media be as kind to it as they have been to Model S?

TeslaTap.com| 04. März 2014@AmpedRealtor - That's a new thought!

I think you could be right. Hopefully the best reviewers are smart enough to fit the much lower price into the equation.

AtlantaCourier| 04. März 2014@EQC

Yes, I see that now. I had the square on the wrong term and got carried away with the results.

Brian H| 04. März 2014Mark;

No. It was in one of the early Model E discussion videos, but I have no index of them. Write or call Tesla if you are really concerned.

Gen3Joe| 04. März 2014If they decide to put a 48 kWh battery into the Gen3 there is no way it will make it 200 miles EPA rated range. It will go around 150-160 miles when driven 65mph on the freeway (the only time when range really matters). To me this would be totally unacceptable.

djm12| 04. März 2014When I read "20% smaller", I assume 20% less mass than a Model S 60. It'll be one heck of a challenge to get that at a $40k base price with 25% margin. But the biggest challenge may be to build a $40,000 car that Elon Musk thinks is good enough for Tesla to sell.

djm12| 04. März 2014To differentiate the Model S and Model X from the Model E, it doesn't take marketing genius to determine to pull the range down to differentiate the models. For many shopping at the economy side of the car buying spectrum, 150 mile range is perfectly adequate *if* Superchargers are common. That would still be 50% better than the Leaf or i3.

Gen3Joe| 04. März 2014The Leaf will likely offer a 150 mile range version by 2017

Iowa92x| 04. März 2014Model E will use a 60 kWh battery. Model S base will be an 85kwh, and long range pack will be 110kwh. I think a 100+ kWh pack will be introduced in a few months with the Model X reveal. X needs to hit similar range goals as the S, which means a larger pack is required. No different than ICE SUVs having a larger gas tank than an ICE sedan. Time will tell, we shall see...

Brian H| 04. März 2014The Model E base pack has already been announced as 48kWh. It is smaller, so that will be enough for 200mi.

DutchieN| 04. März 2014I think steel is a step backwards when BMW is already using carbon fibre in the body of the I3. I also hope that the batteries will have a significantly higher density than the current packs. If not, than it would really be a disillusion and it will not look good for Tesla's future.

Every new model a car company makes should be the best car the have ever made!!!

Mark K| 04. März 2014@dutchieN - great companies always do their best work on their latest products.

I don't think we'll be disappointed with what Tesla does on the Model E.

re: Aluminum vs. Steel - by comparison, low end Audi's do use mostly steel.

But the mass of aluminum in a Model E might cost $500 more than the steel it replaces. Given the benefits, I hope Tesla sticks with it for Model E.

Even Ford is switching to it for the F150, which is a price-sensitive truck.

I don't see why Ford would beat Tesla on this front.

RedShift| 04. März 2014I agree with Mark, we need to wait and see regarding the steel body.

Koz| 05. März 2014I don't expect much more use of steel than in the S except for components that the trade off in weight isn't as pronounced or meaningful.

20% reduction in frontal area is not realistic. BMW's 328i is 71" wide. Don't expect much below 70" if any, so likely only a 10% savings in A. Cd is another matter. Coefficient of drag gets very complicated. A smaller vehicle doesn't mean a lower Cd and often mean the opposite, especially when you are trying to maximize utility. Maybe Tesla is encouraged by their conversations with the NHTSA about cameras in pace of rear view mirrors. That would help Cd and A. Perhaps rear wheel skirts will come into play. Expect less dramatic flaring in the fenders. Maybe they have some tricks up their sleeve to direct more air flow away from the tires. The rear underside may slope up more in the transition to the rear of the car.

Model S didn't start with 25% gross margin and don't expect E to either. I think Tesla even stated the goal for the higher volume models would be 20%. Could be wrong about that, but don't expect it soon after introduction either. They may have to wait following gen of cells or untill 2020 full Gigaplant production. Of course they won't be able to lose money on them going in, either.

Expect Model E and other variants on its platform to be introduced in closer proximity than the S and X.

Expect the unexpected. Tesla has shown the industriousness to innovate in every aspect of car manufacturing, selling, and servicing. Perhaps there will be a fixed sized smaller and higher powered battery but optional sizes for higher energy density range extending pack that can be purchased, leased, and/or swapped separately. Perhaps an expansion of their non-traditional buy back program.

RedShift| 05. März 2014I hope Tesla will have made enough technological progress to produce a lighter battery pack for the same capacity as compared to today's cells. That might be a factor in getting the weight down.

Pungoteague_Dave| 05. März 2014The Model S battery pack is already incredibly dense. Further advances in battery technology are not being proposed for the Gen III - just volume cost reductions. It is close to being locked down now in order to make 2017 production goals.

I do worry about this - A Mercedes S class sedan has the same range as the smaller C class that costs a third as much. Relative range is not an issue in the ICE world. For EV's to be more widely adopted, there cannot be range classes. The Model S breakthroughs are range and charging speed. Both must be similar in the mass production versions. Otherwise it will be a compromise compared to similarly priced ICE alternatives. That's a loser.

The distinction between the Model S and lesser Tesla's is the same as the difference between the luxury and average versions from Mercedes - a $35k Mercedes is just smaller and less luxurious/comfortable/sporting than a $100k Mercedes. But it has the same range and effectively the same speed. It uses the same fuel. It goes just as far just as fast. Compromise those elements in the Gen III and it will prove the EV naysayers right.

sbeggs| 05. März 2014@Pungoteague_Dave, well-thought out ideas about what's essential to keep from Model S in the Gen III car.

Mark K| 05. März 2014Dave - I think your point about full functionality is quite true, and believe that point is not lost on Tesla.

It looks like Elon is aiming to have entry level range on the Model E equal to today's MS 60, but at half the price.

I think they will win big with the E.

Mark K| 05. März 2014BTW - further advances in the cell chemistry are absolutely part of what enables a lighter pack with great range.

Elon has often referred to a 33-40% boost in energy density, so I think that is a given. Without it, I don't think the E would make sense.

All Tesla models will get this technology. The S will likely get access to it early for a new extra-high capacity premium priced tier.

lewille| 06. März 2014Indeed Dave,

That's exactly what happened to the 40kwh Model S, they removed it because no one bought it. If they do a low range Model E, no one will buy it either.

AmpedRealtor| 06. März 2014Model S has set the bar, albeit at a much higher price. In my humble opinion, a Gen 3 with an EPA rated range of less than 200 miles would be a major disappointment.

negarholger| 06. März 2014Dave - I agree with Mark that the higher energy density cell is a given... (a) the design needs it and (b) Elon made many references of it ( e.g. the 500 miles battery ). The announcement and financing of the giga factory tells me has the next cell is developed and in road testing.

I see the 2017 sedan lineup as follows

ME - 48 kWh and 200 EPA

ME - 68 kWh and 250 EPA

MS - 85 kWh and 265 EPA

MS - 120 kWh and 350 EPA

Mark K| 06. März 2014Kleist - I think you are spot-on that the MS 60 will go away when the new chemistry is standard.

sharpe222| 06. März 2014not going under 200 because Supercharger network isn't designed for it.

AmpedRealtor| 06. März 2014@ sharpe222,

The Supercharger network is a living organism and we have 3-4 years to go before we see Gen 3. There are a lot more superchargers coming, which will reduce the distance between superchargers. I wouldn't take today's spacing as any indication of where we will be in 3-4 years.

Brian H| 06. März 2014TM may choose to reduce cost and weight instead of increase range.

AtlantaCourier| 06. März 2014I've been trying to ascertain if the $35,000 price point for the Model E is before or after the $7500 tax credit. Does anyone know? And if so, where'd the info come from?

Mathew98| 06. März 2014Musk suggested $35K price point without and fed credits in many of his interview.

Although the credit should be available during initial launch of G3, it wouldn't be available for long as only the first 200K cars (in total) from each manufacturer are eligible for the credit.

Iowa92x| 06. März 201448 kWh won't be enough zap for 200 miles. A Nissan LEAF has a 24 kWh pack and is rated at 70 miles. The Model E will need nearly a 60 battery to hit 200 miles. A 20% smaller car does not mean the battery will be 20% less capacity. Electric efficiency doesn't work that way.

negarholger| 06. März 2014@Iowa92x - that is the design challenge. A 20% smaller battery only gives you 20% cost reduction... but you need 50%.

Comparison with the Leaf is not valid, different design.

AmpedRealtor| 06. März 2014I wanted to know how many lbs of car weight over a mile are moved per kWh for each vehicle. Here is my calculation, please correct if wrong:

[curb weight in lbs] ÷ ([battery size in Wh]/[EPA rating in miles])

Nissan Leaf curb weight = 3,277 lb

Nissan Leaf battery size = 24000 Wh

Nissan Leaf EPA rating = 84 mi

(3,277 lb) ÷ (24000 Wh / 83 mi) = 11.33 lb miles per Wh

Model S curb weight = 4,637 lb

Model S battery size = 60000 Wh

Model S EPA rating = 205 mi

(4,637 lb) ÷ (60000 Wh / 205 mi) = 15.84 lb miles per Wh

Is the above correct, showing that Model S moves 40% more weight over a mile per Wh than the Leaf? If so, and I didn't screw up my math too badly, it might be possible to get to 200 miles with a 48 kWh battery. I got a B in high school physics, but that was over 25 years ago... I'm sure the above is wrong, if I were better at math I wouldn't be a Realtor. haha!

AmpedRealtor| 06. März 2014If I got the above math wrong, please ignore... Assuming above is correct, assuming Model E will have the same efficiency as Model S, and solving for the weight variable gives us a curb weight for Model E of 3,789 lbs.

negarholger| 06. März 2014BMW 3 sedan = 3,295 lbs... Tesla engineers still have some work to do to get Model E closer - 20% from size and another 10-20% needed ( e.g. less new cells )

Iowa92x| 06. März 2014Article states a 48 battery should give the Model E a 150-ish mile range. Amped, the Model E will weigh more than 3,700 lbs. A Honda Accord weighs 3,500. E will be at least 4k pounds, battery is a pig. Steel body panels vs. aluminum, too.

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