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12V battery problem

Discussion in 'Gen 3 Prius Technical Discussion' started by medicis2, Nov 1, 2020.

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  1. medicis2

    medicis2 New Member

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    (Copied from Gen2 subforum as the issue is generic and there must be more users here)

    Please pardon the long story. I thought details might help with a diagnostic.

    After parking quite normally overnight, I unloaded some stuff (doors open maybe 5-10min) then I vaguely remember not seeing the flashing lights when locking with the fob, which would make sense because I had no problem opening the door an hour later, just to find the battery dead as a doornail. No "ready" light. I turned the visor light on to confirm: faint glow for just a few seconds.

    No access to the 12V battery. So I tried to charge it via the jump start posts. My charger immediately went into overload protection (current way over 8A). Needless to say, I stopped instantly and did not consider a jump start for fear of shorting my friend's battery.

    An ohmmeter test across the same posts shows no short at all, infinite R. (???)

    Is it usual for a dead battery to exhibit a short circuit? This would be the better news.
    Or is the short elsewhere? Ouch!

    I hope the electronics have not suffered from my charging attempt. I guess they were disconnected: the fob was NOT in.

    I would appreciate any insight you Prius gurus can provide before I "invest" into towing... Thanks.

    Philippe
    Prius 2007
     
    #1 medicis2, Nov 1, 2020
  2. ASRDogman

    ASRDogman Senior Member

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    You need a "regular" charger, and/or one that you can put 4 amps or less into it.
    Maybe slow charge it to bring it back to life.
    Any 12v charger will work. If you have one for a flashlight or something like that.
    miliamps. It's slow, but overnight should bring the charge up to use your regular one.
    Or at least make it easier to jump start.

    If you jump from another car, just connect the batteries. He shouldn't need to run the car.
    Let it sit for 2 or three minutes, then dry to "ready" your Pruis.
     
    #2 ASRDogman, Nov 1, 2020
  3. bisco

    bisco cookie crumbler

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    welcome!

    how old is the battery?
     
    #3 bisco, Nov 1, 2020
  4. Grit

    Grit Senior Member

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    Copy and paste this to all the others prius generations also, wouldn't want them to miss out.
     
    #4 Grit, Nov 1, 2020
    jerrymildred likes this.
  5. jerrymildred

    jerrymildred Senior Member

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    WOW! Deja vu!! Seem like I just responded to this question a few seconds ago on the correct forum.

    I just reported it, so maybe it'll get merged and avoid another double conversation fiasco.
     
    #5 jerrymildred, Nov 2, 2020
  6. Tideland Prius

    Tideland Prius Moderator of the North
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    #6 Tideland Prius, Nov 2, 2020
    jerrymildred likes this.
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