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Acceleration and Weight

Discussion in 'Model S' started by tomanik, Apr 29, 2011.

  1. tomanik

    tomanik Member

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    #1 tomanik, Apr 29, 2011
    Last edited by a moderator: Apr 29, 2011
    A post from a while ago got me thinking about the stated acceleration time of the Model S in that it maybe low. I took a look at some other 'ev' vehicles to compare against and thought I would post this out of interest.

    Based on my simplistic view, it seems likely that the Model S is either much heavier than 4000lbs, the available power is less than 300kw or it has the potential to accelerate from 0-60 faster than 5.6 seconds.

    attachment.php?attachmentid=1739&d=1304092449.gif

    Some of the information Sources:
    Tesla Roadster - Wikipedia, the free encyclopedia
    Tesla Model S - Wikipedia, the free encyclopedia
    BYD e6 - Wikipedia, the free encyclopedia
    General Motors EV1 - Wikipedia, the free encyclopedia
    Toyota RAV4 EV - Wikipedia, the free encyclopedia
    Fisker Karma - Wikipedia, the free encyclopedia
    Mitsubishi i MiEV - Wikipedia, the free encyclopedia

    ev.gif
     
  2. Eberhard

    Eberhard #421 Model S #S32

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    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.
     
  3. TEG

    TEG TMC Moderator

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

    Eberhard #421 Model S #S32

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    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
     
  5. TEG

    TEG TMC Moderator

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

    suxxer ElektroVolt

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    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?
     
  7. VolkerP

    VolkerP EU Model S P-37

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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.
     
  8. gg_got_a_tesla

    gg_got_a_tesla Model S: VIN P65513, Model 3 Res Holder

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    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:).
     
  9. goyogi

    goyogi Member

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    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.
     
  10. suxxer

    suxxer ElektroVolt

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    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.
     
  11. VolkerP

    VolkerP EU Model S P-37

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    140kg that's two average people from india/asia or one fat ass from Europe/USA :biggrin:
     
  12. William13

    William13 Member

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    #12 William13, Nov 9, 2011
    Last edited: Nov 10, 2011
    I suggest suxxor also consider the Panasonic battery weights. They are slightly different.
     

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