Acceleration and Weight

For acceleration, not only the power takes in the account, most important is the possible torque = current. The PEM of Model S will deliver around 1000A thats 40% more then Roadster or 25% of Roadster Sport. And the ac motor will spin max 16.000 rpm instead of 14.000 of the Roadster. means the can use a higher reduction rate at the gearbox. next, you have to think about the grip of the tire. Roadster come with hight performance tire, but they are expensive and wear out fast. What will be an economic choice for Models S. Also think about the weight balance between front and back. The roadster has most of his weight on the back. Maybe Model S may need 4 wheel drive to optimize acceleration too.

The shape of the torque "curve" matters too... Just showing max kW doesn't tell the whole story.

ok i forgot to tell, the the torque is on a constant highest level until it hits the peak power, than the power stands quite constant but with increasing rpm, the torque will come down

BTW, Chart has a ? for RangerEV trans. It is a 1 gear too.
"3:1 single speed reduction integrated with motor and differential"

I wonder how the different battery packs (additional weight) will affect the actual acceleration times. I guess that the larger packs (8000 cells) will be far more heavy than the smaller packs (5000 cells), so the acceleration times should vary a bit.

Anyone know more about this?

suxxer said:

I wonder how the different battery packs (additional weight) will affect the actual acceleration times.

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All types of speculation emerged around that issue. Some state that the smaller packs will be padded with ballast weight (IMO complete bunk). Some thoughts go on the power limitation of smaller pack, thus limiting acceleration as soon as it becomes power-limited, and the 5.6 s will not be achievable with the 160 pack. Some say the weight difference is <120lbs and will go by unnoticed. But no facts here.

VolkerP said:

All types of speculation emerged around that issue. Some state that the smaller packs will be padded with ballast weight (IMO complete bunk). Some thoughts go on the power limitation of smaller pack, thus limiting acceleration as soon as it becomes power-limited, and the 5.6 s will not be achievable with the 160 pack. Some say the weight difference is <120lbs and will go by unnoticed. But no facts here.

Click to expand...

I think the 300 pack will be significantly heavier going by what Musk said recently about having to tune the suspension differently for the heaviest pack. The power draw levels will most likely make the difference and even out the acceleration across all pack sizes. I suspect that the 230 pack will be the 'sweet spot' in various contexts (I rather want it to be coz' I'm getting one :smile.

The 300 mile pack uses different chemistry than the 160 and 230 mile version. The 130 is supposedly upgradable to 230 by adding more batteries. But to go to 300 you have to remove what's in there to put in the 300 mile pack. So I would assume the 300 and 230 packs are similar in weight.

The 300 mile pack uses different chemistry than the 160 and 230 mile version.

Click to expand...

I uses a more powerful cell (3100mAh or 3200mAh), not the standard 2400mAh cell.

So we have the following numbers so far:
160miles pack - 5000 cells * 2400mAh * 3.6V ~ 43 kWh
230miles pack - 8000 cells * 2400mAh * 3.6V ~ 69 kWh
300miles pack - 8000 cells * 3100mAh * 3.6V ~ 89 kWh or 8000 cells * 3200mAh * 3.6V ~ 92 kWh

If we assume around 45 g per cell, the total weight of the pack gonna be:

160miles pack - 5000*45g=225kg (~496pounds)
230miles pack - 8000*45g=360kg (~793pounds)
300miles pack - 8000*45g=360kg (~793pounds)

So we are talking about a minimum weight difference of 140 kg (~300pounds) between the 160miles and the 230/300miles pack.

140kg that's two average people from india/asia or one fat ass from Europe/USA :biggrin:

I suggest suxxor also consider the Panasonic battery weights. They are slightly different.