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Battery at 25%. How long does it have left?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by up2eleven, Sep 10, 2024.

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  1. up2eleven

    up2eleven New Member

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    2011 Prius
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    Two
    I did an OBD battery life expectancy test using the Dr. Prius app and it says the battery is at 25% and at end of life. How much longer might it have left?
     
  2. bisco

    bisco cookie crumbler

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    since it is a 2011, i'd guess around 3 years or a percent of your current miles
     
  3. bkman

    bkman Junior Member

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    The battery is as strong as it weakest element.

    The car measures the voltage on them in pairs.

    Typically, center modules go bad (AKA loose capacity) faster then ones on the sides.

    If you take the battery out, remove the bus bars and recondition all 28 modules, you can
    a) get some capacity back - I've reconditioned successfully modules from 1.5Ah to 4.5-5.0Ah. The original capacity is 6.5Ah.
    b) identify modules that are bad - can no longer pass a load test or have significantly less capacity when comparing to the rest of them,

    Once all good modules are reconditioned and bad ones replaced, the whole battery needs to be balanced. Put the modules in the housing that all negatives will be on one side, connect them with a wire, then connect all positives with another wire and leave the battery for 24-48 hours.

    Just finished restoring my spouse's battery from her 2012 v: she used to run out it fairly fast on car washes (when you are required to put the car into Neutral).

    Did the car wash today and lost only one bar (vs her previously got beeping and begging to put the car into Park ASAP and only a single bar left on the battery).

    Module reconditioning takes time. It took me two weeks to get that 2012 v battery into good shape. Used an automotive 12V bulb as a disharge load (3.5Amps) + a cheap battery meter from Amazon and RC chargers to charge modules back.

    If you have $2500-3000 in the budget, the best way is to buy a new battery from Toyota - you WILL get Gen 4 battery modules. I swapped the old battery for the new one under 3 hours - they only sell cells and the metal housing, all electronics and blower motor needs to be transferred from the old battery to the new one.
     
  4. Grit

    Grit Senior Member

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    Not even lithium or sodium?! Luddites!!!
     
  5. rjparker

    rjparker Tu Humilde Sirviente

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    25% is pretty low if you chose to believe an app from a guy who sold lithium aftermarket’s until he bailed out to sell sodium. Discount codes are widely available. The car wash or traffic light quick discharges and lower mpg are just as definitive and your car will code when the designers believe it is toast..

    Oem is the only guaranteed way to get another ten or fifteen years without having to “recondition and replace” modules frequently. However that solution is an option if low budget trumps reliability. Just don’t allow your budget to get so low that you find domestic animals tasty.
     
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  6. burebista

    burebista Active Member

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    Interesting. I just swapped my traction battery two days ago at dealership here. So I have Gen4 modules? What's the difference compared to Gen3 modules?
    Thanks and sorry for offtopic. :)