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Vampire load and range charge

Discussion in 'Model S: Battery & Charging' started by brianman, Jun 13, 2013.

  1. brianman

    brianman Burrito Founder

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    My understanding is that two of the worst things you can do for the battery is leave it at low (0%) or high (100%) SOC for an extended period.

    Given the current vampire drain behavior, is the concern at the high end a non-issue so far? If yes, then perhaps vampire drain from 100% to (say) 90% should remain "enabled" whenever they reintroduce sleep mode.

    Or am I thinking about this wrong?
     
  2. kendallpb

    kendallpb Model S: P 8061

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    I thought the recommendation was to not leave it sitting at 100%, period. I mean, not instant drive away...but not for hours, to say nothing of an "extended period." If so, then vampire drain doesn't matter much either way. But maybe I've misunderstood the recommendation.
     
  3. brianman

    brianman Burrito Founder

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    The suggestion is that Tesla leave the vampire load in place above 90% such that an owner that foolishly leaves the vehicle at 100% will be "saved" by the vampire load dropping it down to 90% relatively quickly.
     
  4. Todd Burch

    Todd Burch Electron Pilot

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    I'm not a fan of this idea. It encourages energy waste and would introduce unnecessary programming complexity--plus the vampire drain would be too slow. A better solution would just be to have a timer. If the car's sitting above 90% for an hour (and it's not being driven), run climate control to bring the SOC back down to 90%. Perhaps the time before this happens could be user-adjustable, between maybe 30 minutes and 3 hours, and this feature could be turned off completely.

    Or, now that I think about it, perhaps part of the "under your nose" announcement is that the battery has a good amount of reserve charge on the upper end that's protected--and after extensive testing Tesla's determined that more of this high end reserve can be opened up to us for use. Which brings about the possibility that Tesla's protecting enough of the upper SOC region that we don't have to worry about it at all.
     
  5. brianman

    brianman Burrito Founder

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    "Sleep mode does not engage when battery is above 90% SOC." Seems pretty simple to me.

    The rest of your post I mostly agree with though.
     
  6. Todd Burch

    Todd Burch Electron Pilot

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    True--the bigger issue would be that sleep mode wouldn't burn charge off quickly enough.
     
  7. brianman

    brianman Burrito Founder

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    I can say with confidence that it's easy to burn off energy in a Tesla Model S intentionally.

    As an example, when I was getting my HPWC initially installed I was waiting for about 30 minutes for the installer to arrive. I opened all the windows and cranked up the AC to as high as it would go. For entertainment, I maxed out the radio, turned on the lights (including the fogs), the hazards, etc. Basically anything I could do to burn power. Without engaging propulsion at all, I was able to burn off energy fast enough that my "standard" charge had decayed "plenty" to test out the HPWC. :)
     
  8. Todd Burch

    Todd Burch Electron Pilot

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    Sorry, I wrote that wrong. I meant that vampire drain wouldn't burn off energy fast enough.
     
  9. kendallpb

    kendallpb Model S: P 8061

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    Gotcha. Thanks for 'splaining.
     
  10. montgom626

    montgom626 Active Member

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    Screw the Vampire load

    Screw the Vampire load, it is a complete waste of power.
     

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