1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Changing 2004 Prius Hybrid Battery Cells

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Slight, Mar 13, 2017.

Tags:
  1. Slight

    Slight New Member

    Joined:
    Mar 13, 2017
    2
    0
    0
    Location:
    South Florida
    Vehicle:
    2004 Prius
    Model:
    N/A
    OK, i have tore the battery out, and i have volted them all out, and have written the voltage on the individual cells. I think there are 4 POSSSIBLY 5 that need to be changed. I need some expert advice or some educated indication that the 3-4 that i think are bad, well actually are.

    Attached is a pic of the individual cells and the voltage. (i know the terminals need to be cleaned)

    Ok, i think there are 4 possibly 5. they are indicated by a big RED dot under the voltages. i really dont know if the 6.85 needs to be changed or charged. ( i think change)

    any and ALL advice is welcome.

    [​IMG]
     
    #1 Slight, Mar 13, 2017
  2. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    16,470
    8,383
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    That entire pack needs to be charged up and then tested. They are all under the minimum 7.2v.

    The best way to do this is to buy a grid charger from hybridautomotive.com and charge them all up. This will be close to a $500 investment but it'll be the right way to rebuild the batteries.
     
    #2 JC91006, Mar 13, 2017
  3. fotomoto

    fotomoto Senior Member

    Joined:
    Apr 22, 2009
    5,597
    3,771
    0
    Location:
    So. Texas
    Vehicle:
    Other Hybrid
    My that's a lot of corrosion on the end terminals; even the case studs have it. Spend a lot time at the beach or with the windows open?
     
    #3 fotomoto, Mar 13, 2017
  4. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    16,470
    8,383
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    The modules might all still be good, just discharged. The bus bars definitely needs to be all cleaned up. You need to do a full charge of the entire pack, then you can tell if they are all good or not.
     
    #4 JC91006, Mar 13, 2017
  5. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
    6,100
    5,811
    0
    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    Slight,

    I agree with JC1006. Although the pack is quite discharged, they may all be good (or they may ALL be sh*t). I've seen modules worse than that fully recover after cycling and testing. Although you have a few that are in the 6.x range, it's not a done deal that they are bad. I've also seen plenty that are at 7.5 volts and have <1000mha capacity.

    I'd also pull the bus bar strips off and check them again with the meter leads directly on the module terminals.

    Or find yourself a newer wrecked Gen 3 battery to buy, swap out the modules and be done with it. Saves money on test equipment and gets you modules that are probably good for another decade.
     
    #5 TMR-JWAP, Mar 13, 2017
  6. Slight

    Slight New Member

    Joined:
    Mar 13, 2017
    2
    0
    0
    Location:
    South Florida
    Vehicle:
    2004 Prius
    Model:
    N/A
    I live in Florida, there HAS to be a cheaper way to charge these cells. what current @ amp do u need to charge these with? Ill keep an eye on them till 7.8 then see what they drop to after ii let them sit for a half day. the bad one will stand out. but a charger....... the CHEAP method, till i successfully do this, then other funds could be allocated for the upcoming projects.

    The corrosion i am going to go get some supplies to clean them with. I do know over time, copper looses its conductivity, so a replacement of the bus bars may help a little????
     
    #6 Slight, Mar 13, 2017
  7. Sam Spade

    Sam Spade Senior Member

    Joined:
    Dec 3, 2016
    2,036
    1,023
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    And for the other side of the coin........
    If you really do have a few cells that have failed due to age and use, I think it is a fools errand to change them out, unless maybe you have nothing better to do with your time BECAUSE soon after you get it back together it is likely that a few others will fail........and this cycle will be repeated over and over until they ALL are new. Might as well do them all at once, if and when you have more than one that actually fails.
     
    #7 Sam Spade, Mar 13, 2017
  8. Sam Spade

    Sam Spade Senior Member

    Joined:
    Dec 3, 2016
    2,036
    1,023
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    Complete and total BS.
    How exactly do you think you "know" that ??
     
    #8 Sam Spade, Mar 13, 2017
  9. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,777
    48,984
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    some people use a hobby charger. i've seen the models in other battery threads.

    btw, can a mod please move this to the newly created battery thread?:whistle:
     
    #9 bisco, Mar 13, 2017
  10. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    16,470
    8,383
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    You can get more information about charging and reconditioning modules at hybridautomotive.com

    You can recondition with hobby chargers but that will take you a month to recondition an entire pack. If you use a grid charger, it'll take less than a week.

    You should also make sure the battery is properly cooled when you are charging them, if they overheat, they'll expand and start leaking.
     
    #10 JC91006, Mar 13, 2017
(You must log in or sign up to post here.)