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Missing KWh on 90D

Discussion in 'Model S: Battery & Charging' started by Vineeth, May 27, 2016.

  1. Vineeth

    Vineeth Member

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    Greetings! We recently took a long day trip to Leavenworth from Seattle - and drove back the same evening. The car started at a 100% charge... And at the end of the day the trip computer showed 68KWh used and 11% left.

    Given its a 90D, I would have expected it to have closer to 20% left after using 68kwh.

    Do most folks find that the kWh used metric on trips is accurate?
     
  2. jeffro01

    jeffro01 Active Member

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    It's not, never has been. It doesn't account for a number of different areas of power draw. It's been explained in detail before but I honestly can't remember, perhaps someone else does and can provide more substance than I have... :)

    Jeff
     
  3. Max*

    Max* Autopilot != Autonomous

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    Also, wk057 took apart an 85kwh and it's not really 85kwh, I think it was about 80.7kwh or something like that. While the 60kwh was 61.1kwh?
     
  4. Boatguy

    Boatguy Member

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    Over the course of one day the trip meter power consumption should be pretty accurate since there is minimal vampire drain.

    From my calculations, a 90D has about 85kWh available so I agree it should have been more like 20%.

    Where did you see 11%?
     
  5. Vineeth

    Vineeth Member

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    On the battery gauge. I have its units set to % instead of miles.
     
  6. brec

    brec Member

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    The imputed usable capacity is roughly 76kWh (68/0.89 +- rounding errors). That seems a bit low. For my 85D it's around 74kWh.
     
  7. mblakele

    mblakele radial cross member

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    To add another data point, I calculated about 81 kWh usable in my 90D. I charged to 90% and drove to red, with 9 range miles remaining. That used 70.1 kWh according to the trip meter. Figuring 3 mi/kWh for the remaining 9 miles gives me 90% =~ 73 kWh and 100% =~ 81 kWh. That seems reasonable if 10% of the battery is reserve of some kind.

    [​IMG]
     
  8. sorka

    sorka Active Member

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    I've clicked off 72 kWh used with 10 miles left on my P85DL.
     
  9. Boatguy

    Boatguy Member

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    How long (days) since the last charge when you observed this?
     
  10. sorka

    sorka Active Member

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    I've only ever had it that low twice and they were both last year sometime.
     
  11. Boatguy

    Boatguy Member

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    The trip meters only report power used while driving, so if it took a week to use 72kWh, you could have lost 3-4kWh from vampire consumption.
     
  12. sorka

    sorka Active Member

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    It was a single trip without stopping.
     
  13. Boatguy

    Boatguy Member

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    Assuming you started with a 100% charge, that seems kinda low.

    72kWh + (10*320Wh) ~ 75kwH

    I've calculated the reserve on my 90D at about 5kWh, so there is another 5kWh missing in your P85DL.
     
  14. sorka

    sorka Active Member

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    The 85 is really an 81 and has 76 kWh available before it hits it's anti brick buffer.

    My point is it's still better than what most of reporting in their 90 batteries.
     

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