A rather extensive analysis and design exercise

[MassModel3]

Yeah. I was going to say those weight targets look REALLY optimistic. If it is going to be steel, I'd count on more like 3,500-3,800 lbs. My guess is it's going to be a mixed-metals vehicle. Aluminum hood, roof, liftgate, steel fenders and unibody. There's a chance there could be some use of carbon fiber, but at the price targets they're looking at, I'm thinking it's going to be very small amount, and possibly only on the higher-performance/price models.

Pay more for a carbon fiber performance version? I like the thought of that -- lighter, faster, better range for a price. But that would also mean making the manufacturing process more complex instead of less. I don't see it happening, although I'd really like to.

 

[Saghost]

200 Wh/mile does seem optimistic. It is a significantly smaller, lighter vehicle than the Model S though, and that is getting under 300.

If I recall correctly, the EV1 could approach 200 under ideal conditions.

I haven't seen real statistical data on it, but from what I've read online I think Spark EV owners are getting close to that range. The Model 3 will be more aerodynamic and probably close to that weight class, so it's possible I think.
Walter

 

[Model 3]

This is in my opinion very good and thorough analysis, and it looks likely that it will hit right on many points.

But also gives forum participants here right in that he probably has missed a little on the size of the smallest battery.

• Elon has said that TM3 will have a minimum range of 200 "realistic miles".
• Elon has said that "200 realistic miles" is about 240 EPA miles, not 220.
• 44kWh seams like a bit low for even 220 miles EPA. Earlier I had calculated/guessed that a 43kWh battery would be sufficient for about 200 to 210 miles EPA range (very similar range to the TMS60).
• Remember TMS40? If I understand it right, part of the reason not to give this access to the SuperCharging network that the battery was too small, and that the effect would therefore be insufficient without exposing the battery too much hardship.

My guess is that the smaller battery has to be in about 50-55kWh to let it be able to use the SC network. Of course, just like the TMS40, the base TM3 may be disabled from SC, but I hope not...

But batteries of about 50 and 70kWh (or 55/75) seams likely, but I can not give an equally good and thoughtful background for this as the article gave of his choice.

 

[Red Sage]

[SINKING ANCHOR] gets no clicks from me.

 

[MassModel3]

Remember TMS40? If I understand it right, part of the reason not to give this access to the SuperCharging network that the battery was too small, and that the effect would therefore be insufficient without exposing the battery too much hardship.

My guess is that the smaller battery has to be in about 50-55kWh to let it be able to use the SC network. Of course, just like the TMS40, the base TM3 may be disabled from SC, but I hope not...

It was my initial understanding that Tesla actually started making a 40kWh battery, then for production efficiency they moved to a 60 that was software limited to 40 (for folks who had already placed orders for a 40). Others on the forum have said that there were only [always] 60 kWh batteries limited as 40's.

I don't know which is fact, but if the batteries were in fact 60's, then supercharging should be allowed by the battery architecture even if they were limiting charge levels to 40 kWh. In fact, they wouldn't need such a long taper off period at the end of charging sessions. But even if they were actually 40's, I can't understand why the SC network can't just turn down the amperage a bit.

 

[Model 3]

It was my initial understanding that Tesla actually started making a 40kWh battery, then for production efficiency they moved to a 60 that was software limited to 40 (for folks who had already placed orders for a 40). Others on the forum have said that there were only [always] 60 kWh batteries limited as 40's.

That's correct. To my knowledge they never produced any true 40kWh packs, and moved to limited 60kWh packs before any deliveries of the TMS40. But the decision of not offering SC to TMS40 was (probably - to the best of my knowledge) done before the decision to not produce the pack. When it become clear that they would not offer any true 40kWh batteries, the only reason not to offer SC access is IMHO based on that the car was sold with that limitation.

Btw: If I recall correct there was a time when they unsure/unclear if they should offer SC to the TMS60, and if it should be included (as with the TMS85) or as a option. But that it would not been offered to the TMS40 was "always" clear.

 

[MSEV]

Nice read, thanks for posting.
The Model 3 has been on my radar as my second car (after the Model S) and the article was quite encouraging, to my mind.

 

[EVNow]

200 Wh/mile does seem optimistic. It is a significantly smaller, lighter vehicle than the Model S though, and that is getting under 300.

If I recall correctly, the EV1 could approach 200 under ideal conditions.

That figure is better than i3. I expect 3 to have 55 kWh battery with 50 useable for 200 miles EPA. If musk wants more than 200 miles, 3 needs a 60 kWh battery, which will get about 215 miles.

 

[Saghost]

That figure is better than i3. I expect 3 to have 55 kWh battery with 50 useable for 200 miles EPA. If musk wants more than 200 miles, 3 needs a 60 kWh battery, which will get about 215 miles.

They should be able to do better than that. The Model S 60 was rated 208 with a 60 kWh battery. Depending on how you choose to understand the "20% smaller", the Model 3 should be between 60 and 80% of the weight, with presumably better aerodynamics (or at least similar aerodynamics on a reduced surface area,) and improved inverter technology, along with the gearing advantages of dual motors. 60 kWh should easily see them into the 240-260 EPA mile range under those conditions.

 

[the dude]

60kWh is the logical choice from a range and charging point of view

the more interesting question is what will the largest battery in a model 3

 

[pmadflyer]

I'd guess 65 kwh, unless they introduce a battery larger than 85 kwh for the S or X when the GF cells start going into cars. If they use the increased capacity of the expanded GF to increase the car cell production, I have no clue.

 

[LargeHamCollider]

Agreed that the mass targets are too low and 44kWh is too small, I'm betting that the base model 3 is 3750lbs with 50kWh battery and 220EPA range.

 

[YBT]

I feel like a 55kW base model with a 70kW range topper makes sense. This would
a) represent some form of progress in terms of range considering a base 3 will have better range than a base S
b) be in-line with Elon's "200 mile real world range" quotes - which arguably a current 60kW S may not actually fulfil depending on conditions, and
c) allow for super charging in base spec (vital to the success of the 3)

 

[Lloyd]

I don't think 44kWh will give a 220 mile range, and I doubt they will design a pack with foot wells

Why not? I already get 180 miles at 55 mph in the Rav4 EV (Tesla Drivetrain) with a 44 kw battery. 195 miles if you slow to 45.

 

[Vexar]

I found the pack design interesting. It could actually be used differently to improve more clearance when seated. Instead of placing the dibs in the pack inside the footwell, why not place the seats there. This would allow for more headroom for tall people (a real problem in both Model S, BMW 3 series and so on).

I can't help but wonder if a 20700 cell would fit inside the battery pack modules for the Model S. Presumably they would allow for a longer range Model S as well. Personally I dream of a 110 kWh pack for my Model S. It would eliminate a few edge-case range problems I have from time to time.

But very interesting and well worth the read.

We see eye to eye. Something was off about the pack design. Why complicate cooling and heating by having an irregular battery region? Why destabilize the battery pack structurally by having wells sunk in it? Why introduce safety risk by having any part of the passenger surrounded by the lithium in case of a catastrophic failure? Why introduce weight balance issues by having thick and thin spots?
My expectation is that the anode/cathode design will be where some improvements are to be found, and that some part of the pack design will be constant, to reduce engineering spend. Perhaps the cells will be identical but the batteries within the cells will have a different layout or dimension.
That analysis must have taken weeks to research and write up. I'm really impressed.

 

[EVNow]

They should be able to do better than that. The Model S 60 was rated 208 with a 60 kWh battery. Depending on how you choose to understand the "20% smaller", the Model 3 should be between 60 and 80% of the weight, with presumably better aerodynamics (or at least similar aerodynamics on a reduced surface area,) and improved inverter technology, along with the gearing advantages of dual motors. 60 kWh should easily see them into the 240-260 EPA mile range under those conditions.

Weight only gets you so far - as BMW must have realized with i3. Drive train is already so efficient in general for EVs - you can't gain all that much. Leaf gets about 3.7 miles per kWh. I don't expect 3 to be all that much better with a much bigger battery (even though it will be denser).

EV1 kind of efficiency can be got only by 2 seat wierdmobiles - in old testing methodologies. Current EPA 5 cycle test is quite stringent compared to the old methods.

- - - Updated - - -

Why not? I already get 180 miles at 55 mph in the Rav4 EV (Tesla Drivetrain) with a 44 kw battery. 195 miles if you slow to 45.

We are talking about EPA range - not some unrealistic test drives.

 

[the dude]

Why not? I already get 180 miles at 55 mph in the Rav4 EV (Tesla Drivetrain) with a 44 kw battery. 195 miles if you slow to 45.

because Musk has said it needs to be a solid 200 mile range, not just 200 miles in perfect conditions

the roadster has a 53kWh pack but that was very small volume, so it think 60kWh will end up being the smallest pack in a mass market car, the bigger pack also helps with supercharging

the model 3 60kWh pack will charge faster than the model S 60kWh pack which is cool

 

[igotzzoom]

If I can get at least 135 miles range while going 80 most of the way, I'll be happy. To me, that's a "realistic" scenario.

 

[MassModel3]

If I can get at least 135 miles range while going 80 most of the way, I'll be happy. To me, that's a "realistic" scenario.

If that's factoring in extreme cold weather, perhaps.

The first time my S went out in 20 degree weather in heavy snow (heating the battery plus wipers, defrosters, cabin heat, seat heaters, slush on the road), I found out that expected range drops drastically. I used somewhere around 70% of my 60 kWh battery driving 65 MPH or less on a 60 mile round trip, starting in a garage at around 45 degrees, then parking outside for a couple hours at the 30 mile mark while the battery no doubt got very cold again.

This is the type of scenario you might not think about [much] in California, but in the colder regions it's something drivers need to take into consideration and plan for. To get your 135 miles at 80 MPH in cold weather, you're probably looking at another 20 or 30 miles in your warmer climate a the same speeds.

 

[EVNow]

If that's factoring in extreme cold weather, perhaps.

Unfortunately EPA cycles don't take heating/cooling into account. Obviously not a concern for ICE - where heat is free. But significantly impacts both battery capacity and accessory usage.

And how about hilly terrain we have all over the west coast ? I've found the hills can have as much of an effect as highway driving in some cases.