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85D, but this calculation shows the capacity is 68kwh only, what's wrong?

Discussion in 'Model S: Battery & Charging' started by hocharter, Jul 17, 2015.

  1. hocharter

    hocharter Member

    Apr 28, 2015
    HZ, China
    I had my new 85D charged to 456km (rated range on the screen) on a supercharger in Shanghai Last night. I drove to Hangzhou today, 95% freeway, AC on, 110-120km/h cruise control on free way, total 222.4km, as shown in the photos below:

    Charged to 456km last night.
    View attachment 87686

    Summary since last charge:
    View attachment 87687

    For Chinese version 85D, the rated range is still 502km (NEDC), then the rated power consumption per km is: 85kwh/502km = 0.1693wh/km.

    After the trip, as shown in the above photo, 131km left, so the rated range consumed is 456 – 131 = 334km, converted energy = 334km x 0.1693wh/km = 56.55kwh. This is energy consumed according to the rated range shown on the screen.

    However, on the summery of the trip, you can see the consumption is only 45.8kwh. The difference is more than 10kwh. This is too much.

    If 45.8kwh is true energy consumption, then the batter capacity of my car is: 45.8kwh/334km x 502 = 68.84kwh.

    This is a new car, till now it’s less than 1000km so should be no problem of degradation, is the math wrong?

    - - - Updated - - -

    a little mistake in the rated range calculation, the correct should be: 456-131=325km, converted energy = 325km x 0.1693wh/km = 55.02kwh. no big difference.

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  2. David99

    David99 Active Member

    Jan 31, 2014
    Brea, Orange County
    I have been able to get 76.5 kWh out of the battery and I was still able to drive. Probably could have made another 10 miles. I also found a screenshot of a Model S at service where it showed the total capacity as a little over 79 kWh.

    Also the trip meter shows the energy consumption only from when the car is moving. If you stop the car still uses energy but it is not counted by the trip meter.
  3. Matteo

    Matteo Member

    Jul 6, 2015
    Hi. I looked at the numbers but they don't make sense. Is it possible that the car waited for long time parked somewhere and consumed 19 km rated range at the beginning or in the middle of the trip? Between the first and second photo, are you sure you haven't left the car parked for long time somewhere? Consumption that happens when the car is not in drive mode, doesn't count in the trip meter screen and won't be included in the 45.8 kWh. Make sure you don't stop for long time between the two screenshots.

    What makes sense is the second screenshot. It shows that drove 222.4 km and consumed 45.8 kWh. The 85 kWh battery has 75.9 kWh available range until the range display shows zero. Therefore if you started with a full battery and drove all the way until range shows zero, you would have driven 222.4*75.9/45.8= 368.56 km = 229 miles. That's very normal.
  4. Rocky_H

    Rocky_H Active Member

    Feb 19, 2015
    Boise, ID
    I see that mistake by many people, trying to do calculations thinking they get the entire 85kwh of energy to use. The battery management keeps somewhere around 5kwh reserved so that you can't run the battery completely down, which would do severe damage to it.
  5. feif

    feif New Member

    Jul 18, 2015
    battery capacity on p85d only 70kwh ?

    I ran Visible Tesla and got the following
    What do others see ?

    Overview Tab and then Details button :

    VIN: 5
    status: online
    options: [
    Region: Europe
    Year: 2015
    Trim: Standard Production Trim
    Drive Side: Left Hand
    Dual Motor: true
    Performance Options: [
    Performance: true
    Performance+: false
    P85D: true
    Performance Exterior: true
    Performance Powertrain: true
    Battery: 70kWh
    Color: Steel Grey
    Roof: Panoramic
    Wheels: Silver 19"

    rest deleted

    Firmware Version: 2.4.250

    - - - Updated - - -

    Updated visible tesla to 0.50.08 a minute ago and the newer version reports now 85kwh .
  6. hocharter

    hocharter Member

    Apr 28, 2015
    HZ, China
    Thanks for the clarificatino, but this is really confusing and does not make any sense.

    First of all, the actual consumption (since last charge) should match the change of the nominal range, the trip meter should count the consumption even when the car is not moving, just like the ICE car does. Say you drive 50 miles and then stop the car for 10 min with the AC on, then the comsumption rate should increase as well as the energy consumed and this is logic, just like how it works on a ICE car.

    Regarding the mysterious 5kwh reserved or hidden some where, ok assume it's reserved then the nominal range should be set this way:


    With this setup, at least an owner understands that the 80kwh (on top of the hidden 5kwh) is there clearly and its change should match the actual consumption since last charge, the difference, if any, is the battery degradation.

    Does this make more sense?

    PS: the trip I mentioned above, I charged it to 456km nominal range at a super charger then drove it back to my hotel (7 km) at 1:00AM, started my trip in the morning at 10:AM, never stopped the car with AC on, and that't the result I got.
  7. Matteo

    Matteo Member

    Jul 6, 2015

    You are confusing yourself with unrelated details. The car consumes lots of energy when it is parked for long time. I asked you twice about this and you didn't answer it. Now it turns out that you did in fact park somewhere for long time (9 hours) between the first and second photo. The car consumes energy to keep the battery between certain temperature limits. There is also energy consumption for connectivity. If you do any tests, you need to do it when you don't leave the car parked for long time. Let alone overnight, parking for even 20 minutes can mess up calculations depending on temperature.
  8. tezzla

    tezzla Member

    Jul 14, 2013
    Is it possible that the Smart Preconditioning turned on between 1am & 10am? I know I've turned mine off because of the weird times it would start conditioning.
  9. NielsChr

    NielsChr Member

    Oct 18, 2011
    take a look at the picture posted her
    Rated Range for 85 kWh battery | Forums | Tesla Motors
    is is the picture in the post from 19. december by ampedrealtor.

    it should pretty much explain why you can not use all 85 kwh for driving purpose. the battery is almost half the value of the car, so better take care of it.
  10. Hans (Amsterdam)

    Hans (Amsterdam) Active Member

    Feb 9, 2013
    #10 Hans (Amsterdam), Jul 25, 2015
    Last edited: Jul 25, 2015
    First switch over to typical range, this gives a much better indication of real world range than rated range.

    The energy available in your battery (in kWh) until you reach zero KM is : typical range x 0,191
    With a new battery you will probably get 407 typical KM @ 100% charge.
    You will have 407 x 0,191 = 77,7 kWh of energy available until you reach zero range.
    Now it is important to know that you will only see 77,7 kWh in your display when you start your trip at 100% charge and continue to drive until you reach zero range. When you pause during this trip (several hours or days) you will definately see less than 77,7 kWh in your display.
    During stand stil the car looses energy (Vampire drain). This lost energy will not be added to the used energy you see on the screen.

    Typical range @ 100% charge x 0,200 gives energy available until you reach FULL STOP.
    For a new car: 407 x 0,200 = 81,4 kWh.
    81,4 - 77,7 = 3,7 kWh, this is zero mile protection.
    85,0 - 81,4 = 3,6 kWh, this is the brick protection.

    Coming to a full stop VIDEO: Dumbass depletes his Tesla battery - YouTube

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