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Ideal Wh/mile?

Discussion in 'Model S: Battery & Charging' started by jlucero, Apr 21, 2016.

  1. jlucero

    jlucero Member

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    what is the ideal Wh/Mile to match expected range left with actual range? i find that around 275 is an ideal range...of course lower the better...
     
  2. kort677

    kort677 Active Member

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    the only time I am concerned about energy consumption is on long hops while on a road trip. for "normal" daily driving it shouldn't be an issue. I drive and enjoy the performance of the car regardless of the consumption.
    to answer your question, keeping a steady speed helps keeping the numbers down, I average around 280-310
     
  3. sandpiper

    sandpiper Active Member

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    188 wh/km or 300 wh/mile will give you exactly the "rated" range in a P85D (and probably a P90D). I don't know the numbers for "ideal".
     
  4. jlucero

    jlucero Member

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    i guess what im saying is that when my vehicle says on the screen that i have 200 miles left, when i run at 300 wh/mile, i really end up with around 175 miles when all is said and done. when i run at 250wh/mile, i find im much closer to that 200 mile range.
     
  5. DCGOO

    DCGOO Member

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    #5 DCGOO, Apr 22, 2016
    Last edited: Apr 22, 2016
    Why not set the car to display %energy rather than distance, and call it a day? If precise range estimate is important, you are probably better off using the energy display. IMO it is much more useful to know my tank is 25% full, rather than a guess at a distance using a somewhat dubious calculation.
     
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  6. Boatguy

    Boatguy Member

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    That's an option, but then you still need to do the math to convert to Projected range.

    Why doesn't Tesla just create a third display option so it's Rated Range, Energy (i.e., percentage) and Projected Range? They give us projected range anyway on the Consumption tab. Why not let us see it on the Instrument cluster?

    I can imagine at some point they did it for "range anxiety" marketing purposes, but the range is way up now and customers are buying the model/range they want. Give us the facts which reflect our driving conditions and style.
     
  7. Boatguy

    Boatguy Member

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    I just did the math on this to understand it for myself. I charged my S90D to 90%, then drove the car about 10 miles, parked for an hour and a half, drove home 10 miles, and then did the math. The point is that these numbers have minimal vampire loss. Here's the math:

    100% RR = 292
    90% RR = 264

    After driving 20 miles:

    RR = 242
    Battery percentage = 82%
    Consumption last 15mi = 300 Wh/mi
    Projected range = 232

    Projected range / Rated range = 232 / 242 = 95.9%

    Wh/mi to achieve Rate Range = 300 x .959 = 288 Wh/mi

    Implied battery capacity = 288 Wh/mi * 292 Rated Range = 84 kWh

    Implied "reserve" or "anti-brick" = 6 kWh

    In practice, I consume about 310Wh/mi so my 100% range is about 84,000 / 310 = 270 miles

    YMMV!
     
  8. David29

    David29 Member

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    For the 70D, the EPA rated range corresponds to 290 wH/mi. But that assumes all 70 KWH are available for driving, which is unlikely to be true.
     
  9. Aljohn

    Aljohn Member

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    I have noted 3 Ranges in various places in my Model X. 1 - Rated Range; 2 - Ideal Range and 3 - Projected range

    Which is the most important in terms of remaining range to drive?
    What is the difference between Ideal and Rated?

    Is the Projected range calculated by the wh/mile and adjusted as watts/mile history changes?

    Going on a Road Trip in a couple of weeks and need to know which to pay most attention to.
     
  10. AmpedRealtor

    AmpedRealtor Well-Known Member

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    All I know is that in order to get 1 displayed mile = 1 actual mile, I have to drive at approximately 275 Wh/mi. If I drive at a higher consumption rate, 1 actual mile > 1 displayed mile. If Tesla is using 300 Wh/mi = 1 rated mile, why do I have to drive at 275 Wh/mi in order to get real miles to match the displayed range?

    Now when Tesla tests to EPA specs, it must run the car until it literally shuts down. That means past zero. I've never driven past zero. Does the fact that I'm seeing 275 Wh/mi to achieve rated range imply that I have some hidden miles below zero?
     
  11. ran349

    ran349 Member

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    No. It just means that your actual usable kWh is less than what the 300 Wh/mi would imply. My car is the same in that the rated range value is 290 Wh/mi, but I never achieve actual miles = rated miles at that rate. The Battery Monitoring System may be conservative due to uncertainty in the actual measurements, so that there might be some small amount of mileage below zero, but I wouldn't count on it.
     

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