60KWh battery for the Bolt... ¿maybe to big for base model 3?

[ImEric]

I dunno... It's been reported that sub .2 is exactly what they're after ( Tesla Model 3 To Aim For 0.20 Drag Coefficient: Report ). And though they don't often deliver on time, they tend to deliver great engineering.

They got the Model S down to .24, and GM got the EV1 to .195, so who knows? To be honest, I'd rather have a car that I don't mind people seeing me in with a .3 Cd than some extreme aerodynamic design to increase range in a car that I'm embarrassed to drive.

 

[EVNow]

Musk has stated 3 won't be a weird mobile. They also want to sell in large numbers. These would dictate design more than saving $750.

 

[Model 3]

JB Straubel has already stated that they plan for new cells from Gigafactory 1 to have a different, larger form factor (no more 18650) which will allow for greater energy density even using the same cell chemistry.

I know, this is only nit-picking, but is this stated? I know it is stated that this (the bigger cells) will be the optimal cell-format, and I guess by this that it is their plan, but I can't remember to have heard/read that he/they actually have stated that they plan on using this format in Model 3.

 

[ImEric]

I know, this is only nit-picking, but is this stated? I know it is stated that this (the bigger cells) will be the optimal cell-format, and I guess by this that it is their plan, but I can't remember to have heard/read that he/they actually have stated that they plan on using this format in Model 3.

I saw JB Say it somewhere else more recently, but I can't remember where. Here's the first time I heard it, about a year and a half ago.

Tesla - Q2 2014 Earnings Call (2014.7.31) AUDIO - YouTube


25:34 Elon Musk: There are improvements to the chemistry, as well as improvements to the geometry of the cell. So we would expect to see an energy density improvement and of course a significant cost improvement. JB, do you want to add anything?
25:53 JB Straubel: Yeah, that's right. The cathode and anode materials themselves are next generation. We're seeing improvements in the maybe 10% to 15% range on the chemistry itself.
26:09 Elon Musk:Yeah, in terms of energy density.
26:09 JB Straubel: Energy density. And then we're also customizing the cell shape and size to further improve the cost efficiency of the cell and our packaging efficiency.
26:22 Elon Musk: Right. We've done a lot of modeling trying to figure out what's the optimal cell size. And it's really not much. It's not a lot different from where we are right now but we're sort of in the roughly 10% more diameter, maybe 10% more height. But then the cubic function effectively ends up being just from a geometry standpoint probably a third more energy for the cell or maybe 30%. And then the actual energy density per unit mass increases.

 

[GoTslaGo]

Cool, can you imagine a 90kWH in a 20% smaller and lighter S, with Cd <.2!

Let me just enjoy this moment before you guys and gals all pop my bubble...

 

[catmando]

That's interesting. I don't currently have a BEV; I have a Volt. But the #1 question is "How far does it go?" not "What size is the battery?"

I think people would be more impressed by a car that can go 230 miles on 55 kWh, than 220 miles on 60 kWh. I think range is the new horsepower in the BEV world, and it will stay that way until range is on par with comparable gasoline vehicles.

I totally agree I want the 3 to go as far as it possibly can, and if that means a large battery pack so be it. I live in Texass and almost all my relatives live near the Atlantic Ocean so I need good range @70mph.

 

[Model 3]

I saw JB Say it somewhere else more recently, but I can't remember where. Here's the first time I heard it, about a year and a half ago.

Yes, that is the same time I have it from. But thanks to remind me, I forgot this:

25:34 Elon Musk: There are improvements to the chemistry, as well as improvements to the geometry of the cell. So we would expect to see an energy density improvement and of course a significant cost improvement. JB, do you want to add anything?

Here he clearly say that it will be changed. I think I just focused on that what it would change into was not stated, just what they think will be the optimum geometry of the cells.

So I stand corrected

 

[Mad Hungarian]

Cool, can you imagine a 90kWH in a 20% smaller and lighter S, with Cd <.2!

Let me just enjoy this moment before you guys and gals all pop my bubble...

Pop your bubble? Hell, I'm hoping they figure out a way to cram 100+kWh battery in the M3. Superchargers are verrrryy few and far between in my neck of the woods. And it's pretty damn cold 3 - 5 months out of the year.

 

[JBsC6]

I'm a diehard gm owner. Owning Cadillacs and corvettes but the bolt is so ugly I could never buy one.

Hopefully the tesla 3 looks like a small model s...a d has an insane mode...

Can't wait for the reveal to decide if I like the looks and the performance enough to buy one in addition to keeping my corvette and Cadillac cts....

 

[McRat]

I'm a diehard gm owner. Owning Cadillacs and corvettes but the bolt is so ugly I could never buy one.

Hopefully the tesla 3 looks like a small model s...a d has an insane mode...

Can't wait for the reveal to decide if I like the looks and the performance enough to buy one in addition to keeping my corvette and Cadillac cts....

I can't help but smile.

C4 - "Ugliest Vette Evar!!!"
C5 - "Ugliest Vette Evar!!!"
C6 - "Ugliest Vette Evar!!!"
C7 - "Ugliest Vette Evar!!!"

Cadillac's supercharged CTS-V was also hated in the styling dept.

But they kind of grow on you, especially since they are more fun to drive than look at.

(seriously, the C5 FRC was the most beautiful Vette in history, fact )

Gen 1 Volts also. Ugly. Until Gen 2 came out. Uglier.

The Bolt looks OK to me. But I've never bought cars based on styling, ever. I think the ZR1 Vette is sort of goofy looking, but it's a kick in ass to throw around a track. Ditto with CTS-V. Meh, looks like a Star Wars prop. Fun as hell though.

 

[GoTslaGo]

Pop your bubble? Hell, I'm hoping they figure out a way to cram 100+kWh battery in the M3. Superchargers are verrrryy few and far between in my neck of the woods. And it's pretty damn cold 3 - 5 months out of the year.

I was just thinking, why not? If it's 20% smaller than an S, and the max capacity (now) for the S is 90kWH, then 20% less would be 72kWH.... or at least 70kWH.

So if Tesla changes the chemistry, what is it 10400(please correct me, I'm sure I'm wrong about the individual cells)? And can squeeze 100kWH out in the near future (GigaFactory?), then theoretically max 80kWH for the Model 3.

So my 70kWH pack with 20% less car (weight and size)....

Of course, just numbers...

Wait I forgot, if it directly translates into the range, then the 240 miles of the S-70D would become 288 miles of 3-70D (20% more...). 0-60 in 4 sec vs. 5 sec for S-70D.

 

[CarGuy1340]

Keep in mind that drag CD is a function of the aerodynamic efficiency for a given area. A higher cd value on a smaller frontal area is actually more efficient than a lower drag cd on a larger frontal area, such as the Model S. The Bolt could have a drag cd of .26 and still be more efficient than a Model S. I would guess the Bolt does 218 miles per charge.

 

[techmaven]

Keep in mind that drag CD is a function of the aerodynamic efficiency for a given area. A higher cd value on a smaller frontal area is actually more efficient than a lower drag cd on a larger frontal area, such as the Model S. The Bolt could have a drag cd of .26 and still be more efficient than a Model S. I would guess the Bolt does 218 miles per charge.

Chevy claims the Bolt has a Cd of 0.312 and a frontal area of 25.8 sq ft, which gives it a CdA of 8.05 sq ft. That's worse than the Leaf's 7.8 sq ft. Much worse than the Model S's 6.2 sq ft.

http://www.caranddriver.com/flipbook/12-things-to-know-about-chevrolets-30000-bolt-ev#6

Tesla Model S Versus Volt, LEAF, Prius - Car And Driver Aero Comparo Video

The Leaf is rated by the EPA at 30 kWh per 100 miles. Since the Bolt is both heavier than the Leaf and has worse aerodynamics than the Leaf, it will be difficult for it to have better than 30 kWh per 100 miles unless GM pulled some shenanigans in the way they self test and self report. EPA range should come in at under 200 miles.

In any case, for real world range when trying to make charging jumps at highway speeds (65-80 mph), it is clear that the Bolt will be substantially worse than a Model S 60 kWh with such poor aerodynamics.

 

[Jeff N]

The Leaf is rated by the EPA at 30 kWh per 100 miles. Since the Bolt is both heavier than the Leaf and has worse aerodynamics than the Leaf, it will be difficult for it to have better than 30 kWh per 100 miles unless GM pulled some shenanigans in the way they self test and self report. EPA range should come in at under 200 miles.

That's not how it works. The 30 kWh per 100 EPA rating includes charging loss overhead.

The LEAF is actually rated as 107 miles on its 30 kWh battery pack. Simplistically, twice that for a 60 kWh pack would be 214 miles of range. GM has said repeatedly that the Bolt will get over 200 miles of combined city/highway range. In spite of the Bolt weighing ~200 pounds more than a 30 kWh LEAF and being slightly less aerodynamic I see no necessity to doubt their claim. However, I agree that the highway range estimate will likely come in closer to 180 than to 200 miles.

 

[techmaven]

That's not how it works. The 30 kWh per 100 EPA rating includes charging loss overhead.

The LEAF is actually rated as 107 miles on its 30 kWh battery pack. Simplistically, twice that for a 60 kWh pack would be 214 miles of range. GM has said repeatedly that the Bolt will get over 200 miles of combined city/highway range. In spite of the Bolt weighing ~200 pounds more than a 30 kWh LEAF and being slightly less aerodynamic I see no necessity to doubt their claim. However, I agree that the highway range estimate will likely come in closer to 180 than to 200 miles.

Yeah, I was factoring in both higher rolling resistance and higher aerodynamic drag. I figured the two cancelled out the charging efficiency loss metric and the actual useable kWh in the battery wouldn't be 60 kWh. So about 8% charging loss, about 8% rolling resistance + aero, would bring you back to 30 kWh per 100 miles. In relation to a Leaf, the question is more or less useable percentage of the battery. Would be close to 200 though, I'm thinking 190-200.

 

[McRat]

Reality check. Chevrolet's existing technology is exceeding 3.6 miles per kWh (28 kWh per 100mi) in real life driving, not EPA cycles. The Leaf is not really hitting it's EPA number in the real world, especially after a couple years. The Chevys aren't reporting capacity losses.

The Bolt at least in theory will have even better engineering for efficiency. Why? Extending the range with efficiency is cheaper than extending it with battery since battery adds weight, cost, and volume.

 

[EVNow]

The Leaf is not really hitting it's EPA number in the real world, especially after a couple years.

No problem getting 84 miles in my Leaf - in summer.

 

[techmaven]

Reality check. Chevrolet's existing technology is exceeding 3.6 miles per kWh (28 kWh per 100mi) in real life driving, not EPA cycles. The Leaf is not really hitting it's EPA number in the real world, especially after a couple years. The Chevys aren't reporting capacity losses.

The Bolt at least in theory will have even better engineering for efficiency. Why? Extending the range with efficiency is cheaper than extending it with battery since battery adds weight, cost, and volume.

We compare EPA ratings and not anecdotes for a reason... controlled and common circumstances. As for Chevrolet's existing technology, you're just talking about doing less with less. Well, a lighter car is easier with a smaller battery pack. The Model S is actually a car Chevrolet can't achieve with the Volt's level of tech. The Bolt, which hasn't shipped yet, is only approaching that level of tech and we'll have to see it operate in the real world to see how it really performs and degrades. The Bolt's battery tech is already behind Tesla's 2012 specific energy, much less 2015's 90 kWh pack or future packs.

 

[David_Cary]

Whenever people talk aerodynamics and EPA ratings, remember that testing for EPA is done on a dyno. There is some correction for aerodynamics but it isn't real.

What people really care about with an EV is range at 70 MPH (or greater). The EPA range rating will not give this number. And a more aerodynamic car will go further than the EPA rating and a less aerodynamic car will go less than the EPA rating.

So the Bolt may have a 200 mile EPA but will not go 200 miles at 70 MPH (or even 65 probably). It will have a much bigger city range than highway just like the Leaf.

One would think a good highway test would be to run at 70 mph at 50 degrees but it doesn't work that way. Leaf forums are full of this talk because the EPA rating varied over the years but the range at 70 MPH did not change at all. They lowered weight and tweaked city efficiency but highway range is harder to change because it is so aerodynamic driven

 

[e-FTW]

At the end of the day, GM is likely to use a couple of items in marketing this to a new customer segment they have been struggling with. First to market with a long-range BEV will be prime. Will they talk about battery capacity? Probably not. EPA range, definitely.
Once the 3 is unveiled in a few short weeks (!), we will see how Tesla positions its own competitive advantages: technology (AP with more hardware capabilities?), supercharger network (speed of charge is key here, no one touches SCs) and probably damn good looks.
No matter what the logic and numbers states, range and the Supercharger network is huge when selling to non-EV fans. Range anxiety is still a thing out there: just look at the questions people ask you about your EV if you have one.