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Actual range vs. Predicted range

Discussion in 'Model S: Battery & Charging' started by Peter Lucas, Apr 6, 2016.

  1. Peter Lucas

    Peter Lucas New Member

    Joined:
    Apr 6, 2016
    Messages:
    2
    Location:
    San Diego
    Battery capacity degradation over years is of considerable interest to me as a prospective buyer. All of the discussion and evaluation of this issue relies on the displayed range from the cars instrumentation. It would very easy for this predicted range to be much less than actual range.
    Is there any evidence that the displayed range is very close to actual range as the battery ages?
     
  2. TaoJones

    TaoJones Beyond Driven

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    Nov 10, 2014
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    1,299
    Location:
    The Americas
    It's been within 1%-4% as reported by those who have exceeded 100,000 miles. Of course those units are older. AP cars, for example, have only been out for 17 months or so, and a tad less for AWD, and of course much less for those cars with the latest battery/contactor/fuse mods.

    While it's normal to have the concern that you have, please be aware that what's of more direct relevance will be the practical, actual, achievable range relative to the rated range - the latter of which being calculated at 284Wh/mile. In English, if you plan to drive in a rapid manner to Yuma a lot or up into the high desert in winter, the impact can easily exceed 30% of your expected range. The aforementioned 1%-4% after 100,000 miles will be barely noticeable. Even 1%-4%/year will hardly be noticeable relative to the effects of quick hilly driving in cold and/or rainy weather. Luckily for you, you appear to hail from a nice warm, relatively flat place with lots of traffic - so less speeding for you.
     
  3. Peter Lucas

    Peter Lucas New Member

    Joined:
    Apr 6, 2016
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    2
    Location:
    San Diego
    Thanks for your repky, Tao-Jones. A 1 to 4 percent degradation of range would be acceptable overy a long period oF time. But is this the range shown on the instrument display (which is a predicted range)? Or is this the actual range that you would experience?
     
  4. DCGOO

    DCGOO Member

    Joined:
    Nov 24, 2015
    Messages:
    234
    Location:
    Indianapolis, IN
    Honestly, I would recommend switching the IC display over to % battery. I find it much more helpful to know when I am down to a "quarter tank" when I see 25% displayed, than any guessed amount of miles. Most of the time I don't care. But if I think I am running close, I can turn on the large energy display and see what range I have left, based on my actual driving, including lights, HVAC, etc., for the last 5, 15, or 30 miles. If I am going farther than the real range displayed, I know I have to take action.

    The % battery is accurate. The calculated range on the energy display is also accurate, as long as your driving is consistent. You can also display the Nav along side the energy display, and adjust your driving to increase the spread between the numbers.
     
  5. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

    Joined:
    Mar 8, 2012
    Messages:
    12,763
    Location:
    Texas
    The trip graph works very well. Before the trip graph, I just used the projected miles vs. rated range. As long as the projected was more than rated, I never worried about running out (note that mountains and wind will throw rated vs project out, but trip graph will show how you are actually doing so it's easy to compensate).
     

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