ACC Battery drain

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by keith770, Apr 10, 2012.

  1. keith770

    keith770 New Member

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    We have experience dead car, no start conditions with our 07 Prius at least 4 times. The nearest we can figure is that there is a drain when we place the cart in ACC mode, close the power windows then turn it off. This kills the car in less than 3 hours. Has this problem been noticed by anyone else. The last time the hybrid system complained about being in neutral when jumped...we NEVER use Neutral
     
  2. uart

    uart Senior Member

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    Yeah, it sounds exactly like a weak 12V battery issue. Usually after the first time you have to jump it the battery is well on it's way. You need a new 12V battery.
     
  3. JimboPalmer

    JimboPalmer Friend to those who want no friends

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    BTW, I urge you and other owners to never use ACC or IGN ON more than momentarily. READY is your friend, it does not run down either battery, to the point of leaving you stranded.
     
  4. qbee42

    qbee42 My other car is a boat

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    Letting your Prius sit in ACC is just asking for a dead 12V battery; don't do it. After flattening yours four times, it's probably time for a replacement.

    The error message about being in Neutral is a red herring. A low 12V battery can cause all sorts of weird behavior, including odd messages.

    If you need to sit for extended periods, leave your Prius in Ready and Park.

    Tom
     
  5. seilerts

    seilerts Battery Curmudgeon

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    To close the windows, it has to be in IG ON, not ACC. IG ON is a tremendous demand on the 12V battery. It is possible that you have had incomplete shutdowns from IG ON because bus voltage was not high enough to turn everything off.

    Anyway, don't bother testing or charging your 12V battery, because it has been deep cycled too many times. Just replace it.
     
  6. richard schumacher

    richard schumacher shortbus driver

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    Ditto the 12V replacement.

    Just for curiosity, why were you doing that ACC-and-windows dance?