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2012 Prius Plugin with 62k miles - Do I need a new 12v battery?

Discussion in 'Gen 3 Prius Main Forum' started by Rainking, Jan 14, 2016.

  1. Rainking

    Rainking Member

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    Do I need a new 12v battery?

    On (1 push of the power button)

    [​IMG]

    Accessory mode (2 push of the power button)

    [​IMG]

    Ready

    [​IMG]
     
    #1 Rainking, Jan 14, 2016
    Last edited: Jan 14, 2016
  2. bisco

    bisco cookie crumbler

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    no pics. but any who, if ready comes on after 3 pushes, i don't think it's the 12v.

    are the brake lights on when you step on the brake pedal?
     
  3. WilDavis

    WilDavis Senior Member

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    Is the dome light "DIM", does the SKS system seem to work OK, have you had someone do a "Load Test" on the 12V battery? I only see broken icons to your image links! :confused:
     
  4. Rainking

    Rainking Member

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    I fixed the pictures.
     
  5. Randall Cooper

    Randall Cooper Junior Member

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    Our 2011 prius did not last 40,000 miles about 2 years before it went dead.
     
  6. WilDavis

    WilDavis Senior Member

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    I replaced the 12V Aux. (or Management Battery, as the dealer calls it) on my 2009 Gen II (106,000miles) about a month ago - symptoms as described in my last post (eventually BIG RED TRIANGLE of DEATH!!), temp fix by jumping (under the hood) using BoosterPack, then off to the dealer to test/replace 12V battery. Problem solved! :)
    PS: I checked all the service records and found that battery (6+ years old) had never been replaced.
     
  7. bisco

    bisco cookie crumbler

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    from the pics, you need to try charging your battery. if it holds, great. if not, replace it. have you ever drained it?
     
  8. Rainking

    Rainking Member

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    No I have never drained it.
     
  9. bisco

    bisco cookie crumbler

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    kind of surprising, mine is like brand new.

    how do you get those screens? i've never seen them.
     
  10. Rainking

    Rainking Member

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    Push on button once, let navigation boot up, press and hold info and turn lights on and off three times then let go of the info button.
     
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  11. bisco

    bisco cookie crumbler

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    thanks! i'll try it tomorrow. i've always wanted to compare the direct reading to the computer.
     
  12. sillylilwabbit

    sillylilwabbit Active Member

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    You are missing the load test step. That is the step that determines if you need to replace the battery or not.

    1 push: 12.5v

    2 push: 12.2v

    Load test: 11.1v (turn on headlights, full blast heater, rear defrost)

    Ready test: 14.7v


    Those are my results for a 2012 plug in w/ 37.5k miles.


    iPhone ?
     
  13. Rainking

    Rainking Member

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    Thanks. My 1 and 2 push is under 12v. Need new battery?
     
  14. bisco

    bisco cookie crumbler

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    no way of knowing until you try charging it. but if you'd rather just drop a few hundred bucks, go for it.
     
  15. Rainking

    Rainking Member

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    Why do I need to charge it? Doesn't the car do that?
     
  16. bisco

    bisco cookie crumbler

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    not really. it just maintains it. although the pip does charge it when you're plugged in, so maybe it does.
     
  17. Mendel Leisk

    Mendel Leisk Senior Member

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    If that 11.7 is similar to what you'd get, measuring with a multimeter with the car shut down, that's not very good. Especially so if, as you said, you haven't accidentally drained it.

    I'd consider anything under 12.0 near dead. Try a smart charger, and then try testing with a tester that can test CCA. Thr dealership should have the latter.
     
  18. Rainking

    Rainking Member

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    Thanks! Will source a multimeter and report back.
     
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  19. macman408

    macman408 Electron Guidance Counselor

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    Yeah, the nav system is not an accurate measurement tool. Although mine is a previous generation, when it read 11.5V in Accessory mode, the actual battery voltage at the terminals was 12.17V. When the car was off, it was 12.5V, which is what it has been since basically the day I got it.

    My personal feeling is "if it ain't broke, don't fix it." So wait until your car doesn't start (or starts doing weird things), and then maybe you need a new battery. I'm still on my original battery, 6 years in. On the other hand, if you can't afford to have your car not start when the battery dies (maybe because your boss will fire you for being late, or if you live in a war zone and need to be able to make a quick getaway on short notice), maybe it's worth it to you to replace it early.
     
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  20. Rainking

    Rainking Member

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    Yea, decided to just leave it alone lol. Just saw a few post about it and thought I'd check mine.