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Jumping or replacing 12v battery

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by jafca09, Jan 26, 2024.

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  1. jafca09

    jafca09 Junior Member

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    Hi. I haven't used my 2010 Prius in a while, so the 12v battery is drained. When I go to jumpstart it with a portable jump starter, I can turn the car on. Everything seems to be working for about 30 seconds, then it shuts off. The voltmeter read 14.5 while the car was on, before it died. I'm fairly certain I need a new 12v battery, since this happened a few months ago several days in a row (though I was always able to jump it and drive it successfully), but I'm looking for a way to temporarily get the car up and running so that I can drive it to a service center. Any tips?
     
    #1 jafca09, Jan 26, 2024
  2. JC91006

    JC91006 Senior Member

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    Letting a new hybrid sit for extended periods is not a good idea. Rodents can get to them and destroy all the electrical systems. Once the car does start and get to READY mode, it shouldn't shut off after 30 seconds. So if you know for sure you have a dead 12v battery, maybe you can just buy one and have it installed at your home? It's not hard to do and if you have AAA, they might have a service to sell you a battery and also install it at your location.
     
    #2 JC91006, Jan 26, 2024
  3. jafca09

    jafca09 Junior Member

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    If the car does start and then dies a few seconds later while the battery jump starter is still attached, is that a definite sign that it's dead and needs replacing? Any other tips to try (like going directly to the 12v battery in the trunk vs. using what's under the hood)? Appreciate any tips.
     
    #3 jafca09, Jan 26, 2024
  4. Mendel Leisk

    Mendel Leisk Senior Member

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    What's the voltage of the 12 volt battery, with the car off?
     
    #4 Mendel Leisk, Jan 26, 2024
  5. jafca09

    jafca09 Junior Member

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    I only have a cigarette lighter voltmeter, which doesn't seem to work when the car is off (or I'm doing something wrong). It displays nothing unless the car is on; I tested it in another car with a functioning 12v battery and the same thing happened.
     
    #5 jafca09, Jan 26, 2024
  6. ASRDogman

    ASRDogman Senior Member

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    That "power outlet" is only supposed to come on when the car is on,
    or in "acc" mode.
    If you want it to be active all the time, you'll have to run a wire to a fuse that has
    power to it even when the car is off.

     
    #6 ASRDogman, Jan 26, 2024
  7. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah simplest is to get a cheap multimeter.
     
    #7 Mendel Leisk, Jan 26, 2024
  8. jafca09

    jafca09 Junior Member

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    Thanks. I believe I'll need to get it replaced. Given that I don't drive it much, if you have any advice on specific trickle chargers that work with my model, that'd be great!
     
    #8 jafca09, Jan 26, 2024
  9. ASRDogman

    ASRDogman Senior Member

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    How old is the battery?
    Any AGM 4 amp or less charger will work...

     
    #9 ASRDogman, Jan 26, 2024
  10. BiomedO1

    BiomedO1 Senior Member

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    Almost all new car cigarette lighters turn off; rarely will you find one that isn't on the accessory switch. Get a cheap harbor freight $10 meter or free, if you've got a coupon.

    Hope this helps..
     
    #10 BiomedO1, Jan 26, 2024
    Mendel Leisk likes this.
  11. Mendel Leisk

    Mendel Leisk Senior Member

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    Wer'e doing about 5K kms yearly. our '10 practically LIVES on a CTEK 4.3 charger. Durable/reliable charger, comes with quick connect harness you can wire up, or just use the aligator clamps. The current iteration is CTEK 5.

    And just to echo: voltage assessment via the cig lighter socket is pointless; it's only powered when the car is on, and then the reading is meaningless. Spring for a semi-decent digital multimeter; it'll come in handy for all sorts of stuff.
     
    #11 Mendel Leisk, Jan 26, 2024
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