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Dead 12v battery?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Julie_93, Feb 24, 2020.

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  1. Julie_93

    Julie_93 Junior Member

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    Context: For a week or two the "maintenance required soon" message was coming up when I started my car. I just had my oil changed a couple months ago and had a leaky tire replaced a month ago and had them check the other tires while I was there. With the trip odometer around 5000 miles I assumed it was an automatic message for maintenance that I didn't need. There were no lights indicating any other issues. I cleared the message by following directions online that I'd successfully used once before. Afterward, my car wouldn't start immediately, but started on the 3rd try. That was Wednesday night. I drove home, went to work the next day with no issues, then had trouble starting it again on Thursday night but eventually got going. Went out Saturday with 0 issues. Cue Monday morning (today) and now all the dash lights are faintly flashing when I try to start it and the engine won't turn on. I checked the 12v battery and got a reading of about 7.6. I tried disconnecting it at the negative charge, waiting a minute, reconnecting it, and nothing changed.

    Do I need a new battery? Or can I save this one? How would resetting the maintenance indicator cause this? I'm so broke right now with my cat having health issues that insurance won't cover so I'm absolutely trying to find a fix I can do myself, even if it's installing a new 12v myself. Any help or suggestions are appreciated.

    I'm a newbie at doing my own car repairs but I've had the car for 2.5 years and I have extensive experience in non-electrical repairs due to my job (brass and woodwind instrument repair) so I'd like to try my hand at doing my own repairs if I can.
     
    #1 Julie_93, Feb 24, 2020
  2. Jon Bloom

    Jon Bloom Member

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    You can have your battery tested. There are numerous places that offer a free battery test. (Of course, they'll try to sell you a new battery.)

    As for clearing the maintenance indicator, I very much doubt that had anything to do with it. Sometimes a coincidence is just a coincidence.
     
    #2 Jon Bloom, Feb 24, 2020
    Julie_93 likes this.
  3. Mendel Leisk

    Mendel Leisk Senior Member

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    With 7.6 volts, pretty much for certain you need to replace.
     
    #3 Mendel Leisk, Feb 24, 2020
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  4. cyberpriusII

    cyberpriusII Prodigyplace says I'm Super Kris

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    A new 12v for a GenII is around $200, give or take $50. No idea about the 2013, but if I changed out the battery on my 2008, I am sure you can do the '13. Probably a few good YouTube videos that I am sure someone will point you to.

    Or, if PC member Stevewoods was closer, I would suggest you ask HIM to change it.:p> :D:D:D:D:D:D
    kris
     
    #4 cyberpriusII, Feb 24, 2020
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  5. bisco

    bisco cookie crumbler

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    pick up a tractor batery for around 50 bucks and wedge it in there, or get a new cat
     
    #5 bisco, Feb 24, 2020
  6. jzchen

    jzchen Newbie!

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    Which model and year is this Prius?

    moto g(7) power ?
     
    #6 jzchen, Feb 24, 2020
  7. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    #7 JimboPalmer, Feb 24, 2020
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  8. Priuslover09

    Priuslover09 Member

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    How’s your hybrid Battery doing ?
     
    #8 Priuslover09, Mar 3, 2020
  9. mikefocke

    mikefocke Prius v Three 2012, Avalon 2011

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    A battery showing 7 volts has either been in a car that has a component failure that is leading to a slow continuous load on the battery when the car is shut off, has a bad shut off switch, had something like a door left open, was never turned off, or has a battery that has at least one bad cell. 7 volts means less than 25% charged on any type automotive battery. You can test the battery by disconnecting it, charging it overnight, testing it when the charger is disconnected, after 1 hour and after 18 hours. You can also take it to many parts supply stores and they can load test it for you. A Prius 12v battery isn't something special nor does it have to have huge capacity as it only starts electronics which connect the high voltage battery which starts the ICE engine.
     
    #9 mikefocke, Mar 3, 2020
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