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12V BATTERY KEEPS DYING

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Biggiejuke, Feb 15, 2019.

  1. Biggiejuke

    Biggiejuke New Member

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    Hello,

    Why does my car battery keep dying? If I don't start the car within 24H it will fail me the next day.

    It's a Toyota Prius 08 Gen 2. I have replaced the car battery a week ago, but the issue isn't fixed.

    I have some components in the car that are on all the time, but the mechanic says that they drain very low power. Is the 12V/45 Ah battery this weak?
     
    #1 Biggiejuke, Feb 15, 2019
  2. Biggiejuke

    Biggiejuke New Member

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    Components drains like 70 mA at 12 V, less when car is turned off but I really do not know how much less.
     
    #2 Biggiejuke, Feb 16, 2019
  3. tankyuong

    tankyuong Senior Member

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    You have a parasitic drain somewhere
     
    #3 tankyuong, Feb 19, 2019
  4. bisco

    bisco cookie crumbler

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    yes, it is extremely weak, because it only has to fire some relays and computers, no engine cranking.
    prius battery is too small for the component draw. mechanic is thinking about a normal car battery.
     
    #4 bisco, Feb 19, 2019
  5. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    You need to hang an ammeter on the battery, read the drain, then pull fuses until the drain drops to an ordinary background level. Whichever fuse makes that difference... the problem is on that branch. Narrow it down from there.
     
    #5 Leadfoot J. McCoalroller, Feb 19, 2019
    Biggiejuke, Bay Stater, Robert Holt and 4 others like this.
  6. Greenteapri

    Greenteapri Active Member

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    From my fellow Houstonian.
     
    #6 Greenteapri, Feb 20, 2019
  7. GrGramps

    GrGramps Active Member

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    #7 GrGramps, Feb 20, 2019
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