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05 Hybrid Battery cell replaced

Discussion in 'Gen 2 Prius Main Forum' started by Umar Baporia, Oct 30, 2020.

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  1. Umar Baporia

    Umar Baporia New Member

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    Oct 27, 2020
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    Location:
    Marin County
    Vehicle:
    2005 Prius
    Model:
    ----USA----
    My dads 05 Prius got the infamous red triangle and codes: P0A80 P3020. My friend and I who is really handy watched a few YouTube videos and took the battery out and tested each battery. We replaced the bad battery and the battery next to it. We put everything back together and all the lights and check engine lights were gone. The rear fan didn’t turn on and everything seemed great and drove perfect for about 30 minutes until all the lights came back on and the rear fan as well. Now when I checked the obd is said it gave me this code: P3022. Which points to weak cell 22? The battery on the car display seems to be holding a charge and actually seems to be charging and is in the green and stays almost fully charged. Rather then before it would drain fast and and the bars would stay in the purple and at bottom (you could tell something was wrong).

    Does anyone have any recommendations on what we should do next? I was thinking since the battery display shows that the battery is healthy and keeping a charge and getting to the green , is a good sign? Does the battery need to be rebalanced as in discharged and fully charged deeply? Please any suggestions would help. Thank you!
     
    #1 Umar Baporia, Oct 30, 2020
  2. PriusCamper

    PriusCamper Senior Member

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    Vehicle:
    2007 Prius
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    Two
    Welcome to Prius chat... I suspect your problem is that there's 14 voltage sensors (one for each block / 2 modules) and those blocks need to have near the same voltage/be balanced.

    Usually replacement modules will have been reconditioned before you buy them so they'll have better performance / voltage numbers than other modules in the pack. And because you replaced both of the modules in that block (a common mistake) you're doubling down on that block giving different voltage numbers.

    So if you're lucky and you pull that module you didn't need to replace, things might work out. But in general, I never replace a module on a pack until the pack has been reconditioned (each module discharged and recharge 3 times at increasingly deep levels). And then when that time consuming work is done I put the pack in the car and use hybridautomotive.com equipment to charge and balance the pack.

    Old Prius packs will have as low as 50% capacity remaining and reconditioning/deep cycling can restore capacity up to 96%. Here's more info on the basic science of it: BU-807: How to Restore Nickel-based Batteries – Battery University
     
    #2 PriusCamper, Oct 30, 2020
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  3. dolj

    dolj Senior Member

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    May 14, 2012
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    Location:
    Wellington, New Zealand
    Vehicle:
    2007 Prius
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    No not 22, it is indicating it is not happy with one or both of the modules in block 12. Blocks and modules are counted as in the picture below.
    Prius Gen II HV Battery module ID.png
    You could try balance charge/discharging the complete HV (hybrid vehicle) battery for 3 cycles and then see whether it is happier after that.
     
    #3 dolj, Nov 2, 2020
  4. PriusCamper

    PriusCamper Senior Member

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    Vehicle:
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    Model:
    Two
    Your graphic doesn't translate module/block numbers to error codes... This confuses people often and if I was more clear on it I'd correct the graphic. Can you or anyone else for once and for all clarify block code error confusion? Surely there must be link on here that correlates which block code error corresponds to which module/block? I keep thinking I got it figured out but then I realize I'm not certain? You also seem to be challenged by the same problem.
     
    #4 PriusCamper, Nov 2, 2020
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