12 v Aux Battery dying

Discussion in 'Gen 2 Prius Technical Discussion' started by Donald Bellefeuille, May 19, 2017.

  1. Donald Bellefeuille

    Donald Bellefeuille New Member

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    2007 Prius
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    Three
    I have a 2007 Prius with 323,000 miles on it for the past 3 years I have had problems with the aux battery dying. The battery I have was purchased in October of 2015 from a Toyota dealer with a 7 year warranty. From Jan 2017 until April 2017 I was placing a trickle charge on the aux battery and it would last for a week. For the past month the battery would die after one day. I disconnected the battery and put a charge on it and reconnected and the following morning the battery was dead. I also disconnected the supply assembly brake control power. Now I am getting clicking noises from the brakes. If the condensers in the supply assembly brake control power is going bad could this be the reason that I have a dead battery?
     
  2. Sam Spade

    Sam Spade Active Member

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    Doubtful.

    Have you ever checked the charging voltage while the car is "running" ?
    It's possible that it isn't charging right.

    But it is more likely, I think, that your "trickle" charger voltage is too high and it fried the battery over a long period of time.

    Or the battery just failed. Things break, sometimes for no known reason.
     
  3. dolj

    dolj Senior Member

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    I'm going to go with possibly, things break, sometimes for no known reason.

    Also consider if the car is drawing a higher current than it should and never getting to its fully quiesced state. A stuck on relay can do this, or having the keys close enough that the SKS (if you car has this) is always alert.
     
  4. bisco

    bisco cookie crumbler

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    sounds like a phantom drain. can be very difficult to find.
     
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