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Simple Explanation of kWh and Range?

Discussion in 'Model S' started by Black/Black MS, Dec 6, 2016.

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  1. Black/Black MS

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    #1 Black/Black MS, Dec 6, 2016
    Last edited: Dec 6, 2016
    The picture here is the trip summary since my last charge. I started with 100% charge and 265 rated miles (P90DL) and am currently sitting at 65 rated miles.

    These are mostly city miles and I'm a leadfoot so 200 rated miles only gets me 112.2 miles, but what does the kWh number mean? It can't mean how much of my 90kWh charge I've used, since I've clearly used more than that, so I'm not quite sure how to interpret it.

    IMG_5764.jpg


    Edit: Bonus question, since 112.2/200 x 456 = 256, does that mean Tesla rated miles are based on 256 Wh/mi?
     
  2. Trailblazer

    Trailblazer Member

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    #2 Trailblazer, Dec 6, 2016
    Last edited: Dec 6, 2016
    The kWh number is the amount of energy you've used to travel those 112 miles. Notice that 112.2 miles times 456 Wh/mile gives you the 51.2 kWh number.

    Edit: Yes, from those numbers I guess you could conclude that Tesla is using 256 Wh/mile as the basis for rated miles - but in my experience, it's been closer to 300 Wh/mile. I'm guessing that your battery isn't quite calibrated correctly. I've read that usually when you charge to 100% (or close) the BMS calibration happens. So - not sure why yours seems to be off by so much.
     
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  3. RYCO

    RYCO Member

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    #3 RYCO, Dec 6, 2016
    Last edited: Dec 6, 2016
    I posed the same question here and to Tesla in August. I finally got a reply:
    Ryan,


    Thank you for your patience. With all the information given and what we are permitted to share regarding the high voltage battery and the high voltage battery system, we can openly say that the state of charge and the Kilowatt’s used do not directly correlate and are not linear with one another. Attempting to calculate the remaining Kwh with the remaining SOC % (state of charge) will not be accurate using ‘simple math’. The algorithm used to assess the health of the battery is so complicated that Tesla developed an internal program that takes into many variables in order to verify the health of the battery pack. Reassessing your battery pack health, the results have come back in good condition on both occasions.


    Also, to protect the battery, your Tesla will not allow the battery to over-discharge or over-charge itself. The middle ground, is the usable energy (displayed) which is what the vehicle calculates.


    Lastly, thank you so much for your understanding. The length of time to pull certain data from a car can be quite a wait. So we appreciate your time and value your support to Tesla.


    15001 N Hayden Rd
     
  4. RYCO

    RYCO Member

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    Doesn't seem right to me. Sounds like they said, " you wouldn't understand" but the answer I got here was that the kw you show as used 51.2 in your case, is what it used while you were actually moving. it's what was used to use your motors. the other kw was used else where to cool / heat your batteries, ac / heat inside your car etc. Is this a problem?
     

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