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12V drain while sitting in car but nothing active?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by brick, Jun 14, 2007.

  1. brick

    brick Active Member

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    My GF had trouble starting her car after work today. It did all of the usual things that point to a low 12V (wouldn't unlock, wouldn't power up, eventually powered up then failed, and then finally, miraculously, powered up and engaged HSD so she could drive home.) Based on what she told me there's only one thing she did that I think **might** have contributed, though it's fairly hard to believe. And that is that she sat in her car for about a half hour on her lunch break. But all she did was sit...she was in the passenger seat and none of the systems were powered up. The only thing active at the time should have been SKS, right? One wouldn't think that would be enough to kill even a feeble 12V such as the one we carry around in only 30 minutes. The door was open but she had turned all of the interior lights to the "off" position.

    Beyond that I don't have much to go on. The battery was reading ~12.8V on the multimeter shortly after she got home, though I really need to check it again after a few hours. Beyond that it must be either a failing (defective...she bought the car a month ago) 12V, a bad connection, or a random electrical glitch.

    Anything I haven't covered?
     
    #1 brick, Jun 14, 2007
  2. skruse

    skruse Senior Member

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    We have found that sometimes the rear liftback does not close - thereby causing a drain via the interior light. So check all five doors.
     
    #2 skruse, Jun 14, 2007
  3. sagediaz

    sagediaz Guest

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    I worked for News 12 in NYC where we had 19 priuses. The reporters had the same issue every so often. I found that if they did not propperly close the rear hatch the 12v batt would drain even though the interior light was not lit. Now that I bought a 2007 Prius for myself I am constantly consious of making sure I close the hatch propperly. Hope this helps.
     
    #3 sagediaz, Jun 14, 2007
  4. richard schumacher

    richard schumacher shortbus driver

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    Hmm, why in the passenger seat and not the driver's seat? I get the feeling that some small but significant detail has been omitted.
     
    #4 richard schumacher, Jun 15, 2007
  5. brick

    brick Active Member

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    Well, I'm told that nothing odd happened today. She didn't repeat the same lunch-in-the-car thing, though. I'd say it might have been something like the hatch but I've never managed to leave the car with an open door, myself, because it goes berzerk the second you try to lock it with a door ajar. As for the omitted detail theory, who knows. I can either believe her or I can not and I don't have any real reason not to believe her. My guess would be that she sat in the passenger seat so that she wouldn't have the steering wheel in her lap while trying to eat.

    Too bad I don't have one of those snap-around ammeters (yet ;) ). That would be the easy way to answer this question.
     
    #5 brick, Jun 16, 2007
  6. richard schumacher

    richard schumacher shortbus driver

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    It's just that one can easily forget things, or not even notice the cause at the time at the time.
     
    #6 richard schumacher, Jun 16, 2007
  7. SteveSherman

    SteveSherman Junior Member

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    <div class='quotetop'>QUOTE(SAGE @ Jun 14 2007, 04:01 PM) [snapback]461935[/snapback]</div>
    I can guarantee that this happens! I just washed my 2007 Prius and parked it in the garage. No lights were on in the car and as it was in a locked garage I did not lock the car. I noticed the open door light the next day and shut the hatch completly. Next day I went to star the car only to discuver dead 12 V battery. measuerd 4.5 volts. Had to crawl around inside to open hatch and disconnect battery to get it accept a charge (breaker on charger tripped when connected) after about 30 minutes on charge I got it started. I have now decided to lock the car even in the garage as it squeels if you try locking it without the hatch being securly shut.
    Thanks for the heads up or I would not have believed the small amount of draw from the open door warning light would drain the battery to the point of not being able to start the car. :(
     
    #7 SteveSherman, Jun 16, 2007
  8. brick

    brick Active Member

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    <div class='quotetop'>QUOTE(richard schumacher @ Jun 16 2007, 03:10 PM) [snapback]463081[/snapback]</div>
    Very true.
     
    #8 brick, Jun 16, 2007
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