12v dying.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by channing watson, Jan 22, 2019.

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  1. channing watson

    channing watson Junior Member

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    I just got done repairing a reverse polarity-ish jump. (I literally tripped over the cables and they fell in such a way as to cause a reverse polarity arc..yeah, that's my luck). The car was being jumped because the 12v had randomly died. The car was jumped at the front jump location. Blew the DC-DC fusible link and the 120 amp fuse at the battery (plus a few others)

    I fully charged the 12v battery with an imax b6. I get 14v at the terminal in ready mode. I have taken 3 short trips in the car today and the resting voltage of the battery is now at 10.5v

    I have no parasitic draw (.06 amps) when the car is off. The battery is less than 6 months old and still under warranty.

    Any idea beyond a bad battery?
     
    #1 channing watson, Jan 22, 2019
  2. SFO

    SFO Senior Member

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    Any lights displayed or DTCs thrown?
     
    #2 SFO, Jan 22, 2019
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  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Since the car starts, you successfully replaced the 120A MAIN fuse.
    Since you measure 14V when the Prius is READY, you successfully repaired the 100A DC/DC fusible link, and the DC/DC converter was not damaged.

    How much parasitic current draw do you measure? Normal would be around 0.02A.
    How much time was required for the battery to register fully charged by your charger?
    It does sound like the 12V battery needs to be replaced.
     
    #3 Patrick Wong, Jan 22, 2019
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  4. Jmack111

    Jmack111 Member

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    Either the car is not charging or you have a bad battery check the ground from the inverter to the chassis to the negative terminal make sure they all match 0 probably an open ground. So you have voltage and no current draw open ground

    Posted via the PriusChat mobile app.
     
    #4 Jmack111, Jan 22, 2019
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  5. channing watson

    channing watson Junior Member

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    Nope. Nothing showing.
     
    #5 channing watson, Jan 22, 2019
  6. AndrewR

    AndrewR Junior Member

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    Good question. Try a certified toyota mechanic
     
    #6 AndrewR, Jan 22, 2019
  7. SFO

    SFO Senior Member

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    How many hours per week is the vehicle generally in use?
     
    #7 SFO, Jan 22, 2019
  8. channing watson

    channing watson Junior Member

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    .06 amps was the max I got.
    it took about 14 hours to get it fully charged at 5 amps. It had tapered down to .2 amps when I pulled it. ~19k MAH according to the charger, it was at 12.8 resting voltage about an hour after taking it off the charger
     
    #8 channing watson, Jan 22, 2019
  9. Jmack111

    Jmack111 Member

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    When the battery charged up you have dash lights and the screens on right

    Posted via the PriusChat mobile app.
     
    #9 Jmack111, Jan 22, 2019
  10. channing watson

    channing watson Junior Member

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    2 to 6 hours a day usually, I deliver for a living. It sits for a few days here and there
     
    #10 channing watson, Jan 22, 2019
  11. channing watson

    channing watson Junior Member

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    Yep, runs fine, everything is normal before it dies. drove it 3x today about 30 minutes a trip
     
    #11 channing watson, Jan 22, 2019
  12. Patrick Wong

    Patrick Wong DIY Enthusiast

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    When the Prius has all doors, hatch and hood locked, the current draw should be 0.02A. 0.06A is a little high but I don't know if that is because of measurement inaccuracy in your meter or if the car actually has a small problem.

    The 14 hour charging time and the resting voltage both seem normal.

    So your charger indicated that it put 19Ah into the battery? That is interesting. The battery may not fail a test if returned to your supplier.
     
    #12 Patrick Wong, Jan 22, 2019
  13. bisco

    bisco cookie crumbler

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    what makes you think it is not a bad 12v?

    how old is it?
     
    #13 bisco, Jan 22, 2019
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  14. channing watson

    channing watson Junior Member

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    it very well could be, just wondering if anyone had any other ideas. It took a charge fairly normally, not that it means anything. I bought it in July of last year. It's a bosch group 25.
     
    #14 channing watson, Jan 22, 2019
  15. channing watson

    channing watson Junior Member

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    Yeah, 19AH give or take a little. It was at 8.2v when I hooked it up after sitting over night, well past the no-no zone.
     
    #15 channing watson, Jan 22, 2019
  16. bisco

    bisco cookie crumbler

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    new enough, but maybe you fried it. charge it up before you aren't going to use it for a few days. then unsure the voltage, then turn the headlights on and measure voltage drop over time
     
    #16 bisco, Jan 22, 2019
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  17. Jmack111

    Jmack111 Member

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    How much current do you have with the car on like it's charging the battery

    Posted via the PriusChat mobile app.
     
    #17 Jmack111, Jan 22, 2019
  18. channing watson

    channing watson Junior Member

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    not sure, I would have to borrow a better meter or an amp clamp to measure it directly.
     
    #18 channing watson, Jan 22, 2019
  19. Jmack111

    Jmack111 Member

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    That'll tell you whether or not you're actually pulling any current into the battery and if you are you have a bad battery

    Posted via the PriusChat mobile app.
     
    #19 Jmack111, Jan 22, 2019
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  20. SFO

    SFO Senior Member

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    That is plenty of 'Ready' time, if that battery known to be decent.
     
    #20 SFO, Jan 22, 2019
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