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First Timer with battery problems, need help asap

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Cup A Joe, Jun 7, 2015.

  1. Cup A Joe

    Cup A Joe New Member

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    Hey guys, my first post here. So recently my 05 prius with 133,000 miles on it encountered a problem. After having the code tested I found out that 'battery block 9 becomes weak'. I did some research reading around on here and looking on youtube and ordered a couple modules online so I could do the repair myself (being a broke college kid I really couldn't scrap up the money to have it done professionally). All of my modules tested at the 7.92-7.94v range except for one that was at 6.6. I've taken that one out and I'm ready to put in my newly ordered module. My question is in regards to balancing. The module ordered is tested at 7.7 so it will be slightly lower than the other good ones. I've been trying to figure out if the balancing is absolutely neccessary and if so what is the best or cheapest way. I really need to get my car back out on the road and I'm hoping maybe I could just put the 7.7 in and throw the whole thing back in the car. Will the car no longer work if I do that? Or what if I used a charger that is made to charge our lawn mower and things of that nature ( I apologize for not knowing the technical terms behind these :/) and letting that charge up the 7.7 module until its even with the others?
     
  2. bisco

    bisco cookie crumbler

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    it will work fine, but eventually throw the codes back up. every case is different, but if i were in your shoes, i'd just keep doing the whack a mole, (time being more available than cash) and keep trying to learn how to rebalance in the future. there are many good threads here with all the info necessary. make a game out of how long it takes to take it all apart and put it together. like a pit crew, see if you can take a few minutes of each rebuild. all the best!(y)
     
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  3. Cup A Joe

    Cup A Joe New Member

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    Thank you bisco for the help!
     
  4. bisco

    bisco cookie crumbler

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    pleasure.
     
  5. exstudent

    exstudent Senior Member

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    Module replacement in general has short lived longevity (hours, days, weeks). BALANCING is REQUIRED for a better longevity; you'll have to make a custom harness to wire all 28 modules in PARALLEL (positive to positive, negative to negative)

    DO NOT use the "lawn mower charger," unless you wish to be worse off.

    READ for knowledge, equipment, and procedure: Gen II Prius Individual Battery Module Replacement | PriusChat

    EDIT:
    IIRC, the HV Battery ECU will trigger a code if there is more than a .2V difference between the 14 module pairs. Your replacement is already at .2V lower. You really need to rebalance otherwise, you'll be getting P0A80 in hours/days again.
     
    #5 exstudent, Jun 7, 2015
    Last edited: Jun 7, 2015
  6. JC91006

    JC91006 Senior Member

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    If you're going to try and replace modules without rebalancing, I think you should replace the entire block instead of a single module. That way the pair of modules will be matched and won't have different capacity.
     
  7. ChapmanF

    ChapmanF Senior Member

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    Just one caution I'd add to that ... it's pretty human, when doing some complicated task over and over and trying to shave seconds off, to begin to feel "yeah, I've got this down, could do it in my sleep" and to lose some of the attentiveness and focus compared to the first time.

    The battery, however, never stops being a 200+ volt, 100+ amp energy source.

    Be safe....
    -Chap
     
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  8. bisco

    bisco cookie crumbler

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    :eek: good point :eek: