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Worried I killed my hybrid battery

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by a bug, Sep 1, 2022.

  1. a bug

    a bug New Member

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    2008 Prius
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    I got into some pretty frustrating problems with my 08 Prius over the last few months and I would love any advice.

    It started off when I went out of town and let my then-partner borrow the car. She accidentally left something on and killed the battery--then in trying to jump it, reversed the polarity. So then wouldn't start at all. We replaced the battery, but that didn't fix it, so my partner replaced the 100 amp fuse. Then it worked for awhile, but it died again after a month or so. It took a jump, but started dying regularly, more and more frequently.

    So now here we are. It won't start with a jump, all that happened after a 15 minute charge was that the dome light was able to come on very dimly. I think it's entirely possible that the fuse was installed wrong, but I'm also pretty nervous it's the hybrid battery. I'm just trying to figure out if it would be worth taking it somewhere, as I already got another vehicle and the prius is over 200,000 miles (not bad I know but lowers the value) and the body's in really rough shape. Any insight would be appreciated, thanks!
     
    #1 a bug, Sep 1, 2022
  2. dolj

    dolj Senior Member

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    It sounds more like the 12 V battery is questionable.
    A 15 min charge on a fully discharged 12 V battery is totally insufficient. You need to have it on charge for 12 -18 hours to fully charge.

    Go and get your battery tested and replace it if it fails the test.
     
    #2 dolj, Sep 2, 2022
    jerrymildred likes this.
  3. Tombukt2

    Tombukt2 Senior Member

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    Base
    Your dim lights and all that that is your 12 volt doing all that. Your HV battery has nothing to do with lights horn dash lights etc your HV battery is a 211 volt system it's a little bit much voltage for the lights and the dash and that stuff that's why you have a 12 volt you need to make certain that the 12 volt is good that would be one of the main things you can't install the hundred amp fuse backwards a fuse just less power go across it turn it around and it still goes across it it doesn't care about direction if it fits the fuse that is and it's the right amp rating is probably working fine unless you've blown it again.
     
    #3 Tombukt2, Sep 2, 2022
  4. fuzzy1

    fuzzy1 Senior Member

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    Location:
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    Vehicle:
    Other Hybrid
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    Other than the age of the vehicle, nothing in your post points to any hybrid battery problem. It stays completely disconnected until the car's 12V computers and systems are fully booted up and checked out and ready to go. The symptoms you describe are classic 12V problems.

    As dolj already mentioned, 15 minutes is much too brief for 12V battery charging. A proper full charge at a safe rate (about 4 amps) takes many hours. The car should start with just a partial 12V charge (give it several hours), but then you'd still want to perform a full charge so that it doesn't soon go flat again. Priuses are not good at keeping this battery well charged, especially on very short trips or when not in daily use, and older vintages (2009 and earlier) are even slower than newer model years.
     
    #4 fuzzy1, Sep 2, 2022
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