2014 Prius 12V battery suddenly dead, then working after 1 hour

Discussion in 'Gen 3 Prius Technical Discussion' started by SKyu, Aug 18, 2023.

  1. SKyu

    SKyu New Member

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    Three
    My prius died while I was in a store for 30 min, then it magically came back on. It still has the original 12V battery. I had the battery tested at Autozone and was told it is fine but needs a charge. Can I trust this battery or should I replace with new one?

    Today, my prius was driving normally. I parked at the store and came back 30 min later and the car wouldn't turn on. Dim, or flickering dashboard lights. I called a tow truck and waited for about 40 min. I went to get something from the car and the darn thing was on! I was able to drive home but worried it would randomly die again.

    Has anyone had a similar issue? Any advice would be appreciated.
     
  2. JC91006

    JC91006 Senior Member

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    If you have the original 2014 battery, that's 9 years old. it's time to replace it, no matter what autozone says
     
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  3. ASRDogman

    ASRDogman Senior Member

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    The auto parts stores do not understand how the battery works in a Prius.
    It's an AGM battery, and is different from a lead acid battery.
    But even a lead acid battery will "come back to life" on and off when it's on it's last leg.

    Don't forget to charge the battery before installing it for at least 4-6 hours at no more than 4 amps.
    The car will not charge is enough unless you'll be driving for several hours.

     
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  4. rjparker

    rjparker Tu Humilde Sirviente

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    Buy a new battery or it will do it again. The Prius does not need much 12v capacity to start but yours is on life support.
     
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  5. SKyu

    SKyu New Member

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    That's what I thought. Thank you all for your quick responses!
     
  6. bisco

    bisco cookie crumbler

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    and make sure the connections are clean and tight, especially neg to ground
     
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  7. sam spade 2

    sam spade 2 Senior Member

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    Yes. Many.
    Get a new battery.
    You can't trust one that is 8 years old no matter what the (inept) test says.
     
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  8. Grit

    Grit Senior Member

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    Post no 6 is the first thing to do. Start troubleshooting the non cost stuff first.