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Wh/mile on your display can be quite different from actual consumption

Discussion in 'Model X: Battery & Charging' started by Okgo, Aug 15, 2016.

  1. Okgo

    Okgo Member

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    P90DL, 3000miles, got the car on June 1st.

    Displayed Wh/mile is 430ish/mile. Actual is 675wh/mile. 2025kwh has been charged to the car so far. Car is used in Southern California, Did use a lot of A/C.
     
  2. PacManMX

    PacManMX Member

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    Your calculations are probably correct. However, you're probably losing about 4% from your electrical panel to the car, and then another 10-20% due to charging inefficiencies. Also, you're calculations include vampire drain. So both are correct. You can use the 430 as a relative number to compare against yourself and others here (my average after 1600 miles is 370). To calculate true energy costs though you should use the 675 number.
     
    • Informative x 1
  3. TaoJones

    TaoJones Beyond Driven

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    Absolutely the case. Can be no better than 1kW/mile under certain circumstances.
     
  4. emir-t

    emir-t Member

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    Wow. That's only 63% efficient. I thought it was at worst 80% efficient.
     
  5. Okgo

    Okgo Member

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    Really? I think that is too much. you might have a leak.
     
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  6. TaoJones

    TaoJones Beyond Driven

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    No leak. Easy to do with a couple of 45-minute conference calls with the AC running while not driving, plus with Smart Preconditioning on. Happens all the time.
     
  7. chillaban

    chillaban Member

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    Yeah it's worth mentioning the car's Wh/mi counters don't count the time you are not moving (such as preconditioning or using the car as a mobile office, etc).
     
  8. TaoJones

    TaoJones Beyond Driven

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    To expand upon this, what one ends up with is a practical, in town or in traffic effective range versus an on the road range.

    Practical versus the... more ideal or hoped for range, in other words. Which most people who start the day with a full charge anyway will be less likely to notice or about which they care :).
     
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  9. chillaban

    chillaban Member

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    Right, the rated miles number is most useful for answering the "how long can I go after topping off my tank and continuously driving to a destination hundreds of miles away" question. And for that, I find that minus elevation it's easily within 10% of truth, which is a lot more than can be said about a gas car.


    Unfortunately, it's terrible for answering the more common question and very common pre-purchasing preponderance: "I have a 15 mile commute round trip. How many days can I go without charging up, if I live in an apartment and have occasional access to a charger?" Unfortunately you can easily be 2x or 1.5x off using the naive approach.
     
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