Model 3 Battery size

[Model 3]

Why did someone stick post-it notes all over their spaceship?

That's how "spaceship controls" works Be on a lookout for post-it notes on the RC's they are driving around in this days!

 

[Red Sage]

Why did someone stick post-it notes all over their spaceship?

You never know whey you might need to write something down. Or draw a doodle.

 

[R.S]

I guess I should butt in and comment on this. The extra height of the 2170 cells (which is a "free" density improvement) is exactly cancelled out by the smaller width/wheelbase of the Model 3. That makes the missing double stacked module area from the Model S play the biggest factor. So essentially that is a 14/16 = 87.5% factor.
How many kWh can they squeeze into the Model 3...?

I initially used the 100kWh pack to do the estimate which gives 87.5kWh for Model 3. However, that pack has cells more tightly packed. If Tesla uses a packing density more similar to the 90kWh pack, this means 78.75 kWh, which matches more closely to the 75kWh Elon was talking about.

I should note Elon worded the 75kWh carefully. He alluded that this was current technology. That leaves room for Tesla to introduce a larger pack further down the road.

The most important thing we have to keep in mind is that we don't really know if the architecture of the 3 is even similar to the S. The S, like you mentioned, has it's rear motor behind the rear axel and therefore two stacked modules.

Move it forward and you gain more trunk space and a larger crumple zone, while loosing those two stacked modules, which in the Model S's case would be 12.5 kWh. If the front motor also sits where in the Model S the battery would sit, we have even less space for a battery. But there are even more things you could cram in down there, AC compressor, coolant reservoir and pump and so on.

So if they think they don't need more than XX kWh of battery, they would surely find a way to use the extra space.

 

[JeffK]

The most important thing we have to keep in mind is that we don't really know if the architecture of the 3 is even similar to the S. The S, like you mentioned, has it's rear motor behind the rear axel and therefore two stacked modules.

Move it forward and you gain more trunk space and a larger crumple zone, while loosing those two stacked modules, which in the Model S's case would be 12.5 kWh. If the front motor also sits where in the Model S the battery would sit, we have even less space for a battery. But there are even more things you could cram in down there, AC compressor, coolant reservoir and pump and so on.

So if they think they don't need more than XX kWh of battery, they would surely find a way to use the extra space.

On the reveal it appeared that the battery was made up of eight modules... it looks nothing like the Model S/X battery

 

[WarpedOne]

The most important thing we have to keep in mind is that we don't really know if the architecture of the 3 is even similar to the S.

Who is we?
Those of us who saw the M3 introduction, know the architecture in quite some detail. It was shown on the big screen after all...

 

[Red Sage]

The most important thing we have to keep in mind is that we don't really know if the architecture of the 3 is even similar to the S. The S, like you mentioned, has it's rear motor behind the rear axel and therefore two stacked modules.

As others have noted, those of us who have a technical background were sure to have made note of the CAD rendering of the Model ☰ that was being 'built' virtually on the big screen behind Elon Musk on stage during the unveiling. The entire architecture of the innards of the car were there. There are screenshots, likely within this very thread, that show there are eight modules to the battery pack.

On the Model S, the two stacked battery modules are at the front of the battery pack, not toward the rear. And saying the motor is 'behind' the rear axle makes it sound like a Porsche spinmobile. The motor and inverter are entirely between the rear wheels, even though technically they are just behind the rear axle due to the placement of the reduction gear assembly.

 

[JRP3]

And saying the motor is 'behind' the rear axle makes it sound like a Porsche spinmobile. The motor and inverter are entirely between the rear wheels, even though technically they are just behind the rear axle due to the placement of the reduction gear assembly.

So saying the motor is behind the rear axle is 100% correct.

 

[FlatSix911]

So saying the motor is behind the rear axle is 100% correct.

Technically correct for the Tesla. This is what a true rear engine vehicle looks like

 

[JRP3]

This is what a true rear engine vehicle looks like

I did say motor

 

[stopcrazypp]

The most important thing we have to keep in mind is that we don't really know if the architecture of the 3 is even similar to the S. The S, like you mentioned, has it's rear motor behind the rear axel and therefore two stacked modules.

Move it forward and you gain more trunk space and a larger crumple zone, while loosing those two stacked modules, which in the Model S's case would be 12.5 kWh. If the front motor also sits where in the Model S the battery would sit, we have even less space for a battery. But there are even more things you could cram in down there, AC compressor, coolant reservoir and pump and so on.

So if they think they don't need more than XX kWh of battery, they would surely find a way to use the extra space.

Other's beat me to it. We already know how it looks from the unveiling, my calculations are based on that (why I know there isn't the two stacked modules). As you can see in the pictures, the Model 3 uses 8 modules that takes up the same general area as what the 14 non-stack modules takes up. However, the actual physical area is smaller because Model 3 has smaller width/wheelbase.

 

[R.S]

Who is we?
Those of us who saw the M3 introduction, know the architecture in quite some detail. It was shown on the big screen after all...

I saw it and from what I can tell both motors are between the axels. Not like in a Model S where the rear motor is behind the rear axel. And that has consequences for the amount of batteries you can put into the wheelbase.

 

[ProphetM]

Why did someone stick post-it notes all over their spaceship?

You never know whey you might need to write something down. Or draw a doodle.

 

[R.S]

As others have noted, those of us who have a technical background were sure to have made note of the CAD rendering of the Model ☰ that was being 'built' virtually on the big screen behind Elon Musk on stage during the unveiling. The entire architecture of the innards of the car were there. There are screenshots, likely within this very thread, that show there are eight modules to the battery pack.

View attachment 222763

View attachment 222765
View attachment 222768

On the Model S, the two stacked battery modules are at the front of the battery pack, not toward the rear. And saying the motor is 'behind' the rear axle makes it sound like a Porsche spinmobile. The motor and inverter are entirely between the rear wheels, even though technically they are just behind the rear axle due to the placement of the reduction gear assembly.

View attachment 222760

So I went back and looked at the video again and found something to prove my point.

Here we can see the axels of the Model 3, so we can see the whole wheelbase, the battery doesn't really take up 100% of the space between the axels, does it?

Now here we have the Model S. See how the battery pack stretches from one wheel to the other, with the stacked units, like you rightfully corrected me, in the front?

With both motors being in between the axels, the just isn't that much space for a battery. You can still fit 8 modules, but since you don't know how big these modules would be, that's a rather moot point. Now let's just subtract two modules in front and two in back and the Model S would have 75kWh. Use your guesstimation and the Model 3 will have... wait 75kWh? Exactly what Elon said it would be capped at? Impressive!

So while you might have watched the first 9 minutes and 55 seconds over and over again, you probably should have kept on watching for 5 more seconds.

 

[MostlyStock]

Why did someone stick post-it notes all over their spaceship?

Those are Velcro; can't have your stuff in space floating everywhere. Oddly the Crew Dragon doesn't look to have any Velcro (definitely not ready for prime time as shown).

 

[Waiting4M3]

So I went back and looked at the video again and found something to prove my point.
View attachment 222815

Here we can see the axels of the Model 3, so we can see the whole wheelbase, the battery doesn't really take up 100% of the space between the axels, does it?

View attachment 222816
Now here we have the Model S. See how the battery pack stretches from one wheel to the other, with the stacked units, like you rightfully corrected me, in the front?

With both motors being in between the axels, the just isn't that much space for a battery. You can still fit 8 modules, but since you don't know how big these modules would be, that's a rather moot point. Now let's just subtract two modules in front and two in back and the Model S would have 75kWh. Use your guesstimation and the Model 3 will have... wait 75kWh? Exactly what Elon said it would be capped at? Impressive!

So while you might have watched the first 9 minutes and 55 seconds over and over again, you probably should have kept on watching for 5 more seconds.

The M3 picture is only showing the rotors and brake calipers, the MS picture includes the tires. If you put tires on the M3, the battery pack looks like it will also fill the whole distance from one tire to the other

 

[stopcrazypp]

The M3 picture is only showing the rotors and brake calipers, the MS picture includes the tires. If you put tires on the M3, the battery pack looks like it will also fill the whole distance from one tire to the other

Yep, beat me to it. That was the rationale for using wheelbase as an estimate (proportionally it scales roughly the same), although wheelbase isn't really the best metric to use (it should be from the rear of front wheel well to front of rear wheel well, not sure if there is a technical term for this measurement).

 

[R.S]

The M3 picture is only showing the rotors and brake calipers, the MS picture includes the tires. If you put tires on the M3, the battery pack looks like it will also fill the whole distance from one tire to the other

So I found another picture with tires. Sadly you can't see the pack anymore, so I "photoshopped" the tires into the picture where we can see the pack.

This is by no means perfect, but it should still illustrate my point. Both motors take up space that is used for batteries in the Model S.

 

[scaesare]

The M3 picture is only showing the rotors and brake calipers, the MS picture includes the tires. If you put tires on the M3, the battery pack looks like it will also fill the whole distance from one tire to the other

In my opinion, the renderings of the M3 above make it appear the pack doesn't extend quite as far fore and aft. It appears there's more drivetrain mass pushed forward of the rear axle, and mechanicals behind the front "axle line".

When compared to the Model S:

With that rendering showing each end with and without a tire, it appears the mechanicals are spread out farther, impinging in to the center belly pack area less.

You can see the extents a little better in these... in the front clearly the double-stack intrudes deep in to the center section between the front tires:

But from below, you can see the rest of the full-width section of the pack push forward enough to just clear the front wheel turning radius:

The rear section has a small section that extends aft to house the connectors, but the main "module" section comes right up to the edge of the rear wheel arches would be:

The difference between the S and 3 isn't huge, but I do think it's there.

In short, it appears the 3:

- Has no "double-stack" module section
- Has a shorter overall wheelbase
- Has slightly more mechanical intrusion inboard of the axle-lines

All of that equates to a max of 75kWh of capacity, even utilizing the newer cell size/chemistry.

 

[Sonny Daze]

The more weight that is moved toward the center of the vehicle the happier I will be. 70/75 kWh is plenty for me.