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12v battery check

Discussion in 'Gen 3 Prius Technical Discussion' started by socal13, Feb 8, 2018.

  1. socal13

    socal13 livin in the foothills...

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    I have a 2013 Persona gen 3 with nav and I am trying to find out how to check the 12v battery. This may have been discussed many times but I can't find it. Thanks for any advice.
    Doug
     
  2. bisco

    bisco cookie crumbler

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    get an inexpensive volt meter, pop the hood in the evening, and the next morning, open the hood and check the voltage at the jump point in the fuse box.

    this has been my go to method for 14 years, and hasn't failed me yet.
     
  3. Mendel Leisk

    Mendel Leisk Senior Member

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  4. socal13

    socal13 livin in the foothills...

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    Thanks bisco!
     
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  5. bisco

    bisco cookie crumbler

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    pleasure.
     
  6. socal13

    socal13 livin in the foothills...

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    I just checked the voltage using your system and I got a reading of 12.4v. The car is a 2013 with original battery so just about five years old and 36k miles. Does this sound about right?
     
  7. Mendel Leisk

    Mendel Leisk Senior Member

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    Sounds low, 12.6 would be better. An electronic load tester (such as the one I mention above) would also assess the Cranking Amps, and give a verdict, suggest a course of action. They're about $60 in the States I think.

    Another good item to have is a smart charger, 3~4 amp range. Use it periodically, or even just leave it on indefinitely (installing a quick-connect makes this easier) if the car is regularly idle for multiple days.
     
  8. bisco

    bisco cookie crumbler

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    yes, except how long was it since the car had run, or since you opened a door?
     
  9. socal13

    socal13 livin in the foothills...

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    The car had not run but I was opening doors and fooling around with acc trying to get a readout on the screen.
     
  10. bisco

    bisco cookie crumbler

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    that can effect it. try my method and repost in the morning.
     
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  11. Danny3xd

    Danny3xd Active Member

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    Just a thought and option. A charger is cheap and a great thing to have around. So when the battery does fail, watch a YouTube vid, start your car and go buy a new one. Really easy to instal. (Again with the vids) Most places will install for you when ya buy a battery .

    Just an another approach. But then it's not a choice of replacing and wasting money or being worried that you'll be stranded.

    Left dome light on the other night and started fine. My battery is older and doubt a meter test would not suggest replacing.

    Have seen never used and in the box chargers at yard sales for 2 bucks.

    Great advice above. This is just mine and will be insurance for other cars as well.
     
    #11 Danny3xd, Feb 8, 2018
    Last edited: Feb 8, 2018
  12. socal13

    socal13 livin in the foothills...

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    You got it doctor!!
     
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  13. Danny3xd

    Danny3xd Active Member

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    Wut he said, ayup
     
  14. Danny3xd

    Danny3xd Active Member

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    [​IMG]

    Free'bee at HF. It's a cheap one but works fine and can't beat the price.

    Pic didn't copy. But if you go to harborfreight.com , they have a flyer, email and also gives you a % off coupon.

    If ya have any trouble ,lemme know. Hope it helps.
     
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  15. socal13

    socal13 livin in the foothills...

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    I did your method and this morning's reading was 12.52v.
     
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  16. bisco

    bisco cookie crumbler

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    that's not bad, mine is 12.4, but i have the advantage of charging every time i plug in.
    you could be fine for years, no way of knowing. check it once a month or so, unless you'd rather just change it prophylactically.
    on major thing imo is whether or not you have ever run it down. if you have, that weakens it. if not, it should still be strong.
     
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  17. Danny3xd

    Danny3xd Active Member

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    hehe. You said prophylactically


    Wut?
     
  18. Mendel Leisk

    Mendel Leisk Senior Member

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    That's actually a valid usage, means as a preventative measure. But yeah...
     
  19. Danny3xd

    Danny3xd Active Member

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    Been up working all night and laughed so hard the cat ran out of the room.

    Yes, nap time and my apologies .
     
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  20. Mendel Leisk

    Mendel Leisk Senior Member

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    Here's a video discussing the various ways to test a battery, ending up with the Solar BA5. My only affiliation: I bought one, found it does what it's supposed to do. A voltage check is just that. A good first step, but not a good predictor of where you're battery's at. The BA5 and it's ilk do an electronic load-test of Cold Cranking Amps, and give a rudimentary verdict and course of action.

     
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