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Stumped -12v dies every week or so

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Charley Gosse, Jan 3, 2020.

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  1. Charley Gosse

    Charley Gosse Junior Member

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    Location:
    McLean, Virginia
    Vehicle:
    2006 Prius
    Model:
    II
    My 2006 Prius 12v battery dies every now and then and I can't figure out why. I carry a booster that gets it back up and running. Used to be every 3 months and then every month and now once a week. I can't figure-out why this happens.

    I checked the battery's voltage using the front panel display check* that I learned about here on the forum. The reading for the 12v battery is 12.1 volts and then when I fully power-up it is 14.1 volts so that seems ok.

    I bought the car new in January 2006 so it's 14 years old. I don't remmebr every replacing the 12v battery. Ofcourse, they don't last forever. Should I just replace it with a yellow-top or do any of you folks have suggestions as to why it might be dieing?

    It does seem to happen most often when my wife has been driving it but I can't figure out what she might be doing to cause this.

    Charley

    * processed followed:
    turn off lights and car
    press power with foot off brake
    hold display button while switching lights from off to parking light 3-4 times
    display shows a menu
    select "display check"
    select "vehicle signal check"
     
    #1 Charley Gosse, Jan 3, 2020
  2. bisco

    bisco cookie crumbler

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    nothing to figure out, 14 years may be a new record. replace it :p

    is it possible she uses acc mode at all, or puts the car in neutral when stopped?

    i went with oem = $200.

    some have found around $150. at auto parts stores or batteries plus bulbs.

    optima gets good and bad reviews, hard to say.
     
    #2 bisco, Jan 3, 2020
    SFO likes this.
  3. dig4dirt

    dig4dirt MoonGlow

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    replace that puppy.

    oem has proved to you that they last a while in your conditions.

    Yes, 14 years I think may be a record, or at least in the record books!
     
    #3 dig4dirt, Jan 3, 2020
    Mendel Leisk likes this.
  4. dolj

    dolj Senior Member

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    I would say no, these Optima batteries are not what they once were. Don't expect it to last 14 years.

    You got 14 years out of an OEM, so why not just go with another? $300 ÷ 14 years = $21.43 per year. Pretty cheap in the long run.

    PS you can probably do better than $300 by shopping around – I just used that figure for illustrative purposes.
     
    #4 dolj, Jan 3, 2020
  5. The Electric Me

    The Electric Me Go Speed Go!

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    I contacted Hercule Poroit about the "Mystery of the Dying 14 year old battery". He say's just replace it. It died of natural causes.
     
    #5 The Electric Me, Jan 3, 2020
    edthefox5, GrGramps and dig4dirt like this.
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