2010 Prius Upgraded Hybrid Battery Question for technical help

Discussion in 'Gen 3 Prius Technical Discussion' started by spgview211, Dec 7, 2025 at 7:53 PM.

Tags:
  1. spgview211

    spgview211 New Member

    Joined:
    Sunday
    6
    1
    0
    Location:
    Bay Area,Ca
    Vehicle:
    2010 Prius
    Model:
    Four
    I purchased a 2010 Prius, according to the previous owner the hybrid battery was changed at some point. I thought cell/modules were original ,until I removed the battery and put eyes on it. Unsure if
    The car remained parked for a long time and discharge due to non use.

    I plan to recharge or rebuild and balance the pack after determining which module is bad. I want to charge and discharge 3 times and record the mah on each cell. I purchased a Tenergy T180 charger to help.

    Discovered the cells are cylindrical in shape and green and 14 total. Each section say 6.5AH and has 4.4V stamped with “Electron electric vehicle experts.” Appear to be 3 rows tall in each module.

    I’m trying to figure out the following:
    1. What voltage to charge each individual module? And how many Amps? I read online it might be 14.4V but want to confirm nothing indicate on the battery. Other than 4.4v and 6.5ah

    2. What amp to discharge and to what voltage to not damage the cell/module?

    I’m including pictures of the current voltage after being removed without charged.
    I just realized I labeled them backwards 1 should be closed to the fan.
     
    #1 spgview211, Dec 7, 2025 at 7:53 PM
  2. spgview211

    spgview211 New Member

    Joined:
    Sunday
    6
    1
    0
    Location:
    Bay Area,Ca
    Vehicle:
    2010 Prius
    Model:
    Four
    +photos
     

    Attached Files:

    #2 spgview211, Dec 7, 2025 at 7:54 PM
  3. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    113,987
    51,908
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    #3 bisco, Dec 7, 2025 at 9:25 PM
    PriusCamper and indel like this.
  4. spgview211

    spgview211 New Member

    Joined:
    Sunday
    6
    1
    0
    Location:
    Bay Area,Ca
    Vehicle:
    2010 Prius
    Model:
    Four
    Thanks for the response. All of these video work with stock cells(28) per pack.

    I have updated cylindrical cells that are 14.4V and consist of (14) total with higher voltage in each.

    similar to this upgrade.



    Cannot seem to find a video of a rebuild or any post outlining reconditioning. Here’s a photo of the pack - all help is appreciated .
    Do I charge to 17.0v-18.0v @ 6500 MAH .8 amp?
    Discharge at 1 amp to 12.5V ?
     

    Attached Files:

    #4 spgview211, Dec 7, 2025 at 9:45 PM
    bisco likes this.
  5. indel

    indel Member

    Joined:
    Apr 1, 2024
    94
    33
    1
    Location:
    Northwest Indiana
    Vehicle:
    2012 Prius
    Model:
    Two
    @spgview211 I recommend doing a consultation with @ericbecky. He has a ton of experience with hybrid batteries.
     
    #5 indel, Dec 8, 2025 at 9:22 AM
  6. spgview211

    spgview211 New Member

    Joined:
    Sunday
    6
    1
    0
    Location:
    Bay Area,Ca
    Vehicle:
    2010 Prius
    Model:
    Four
    Appreciate the insight, I’ll tag him and see if he can offer pointers. I looked him and he’s on the East coast.
    I set my charger to .8 amps and it charged to apx 17.0 V @ ~2500 mah before timing out (200min safety). I increased to 2.0amps @ 600 minute safety cut-out.
    @ericbecky

    Quick question: Do I set my charger to 6500mah or higher to 8500mah? I plan to discharge at 1.0amp (or higher based on feedback) to try and recondition these cells and figure out which one is bad before rebalancing/ rebuilding.
     
    #6 spgview211, Dec 8, 2025 at 10:38 AM
  7. BiomedO1

    BiomedO1 Senior Member

    Joined:
    Mar 27, 2021
    3,591
    1,857
    0
    Location:
    SacTown, Ca
    Vehicle:
    2021 Prius Prime
    Model:
    LE
    IMHO; your best bet is to try to find OE markings on the battery modules and do a search for their specifications. There were several iteration of after market cylindrical battery systems made, so the only way to get accurate specs. is to contact the seller of that pack - if they're still around. I personally wouldn't consider a cylindrical module pack to be an upgrade when compared to Toyota's track record of their traction packs.
    The worse news is that you have an INVALID traction battery core, if you decide to buy a new one from Toyota. Toyota won't accept it, so you'll also lose your core charge in that transaction.
    FWIW; the gen1 Honda Civic Hybrids used cylindrical modules too; I got about 70K miles before it needed replacement - luckily still covered under warranty due to CARB rules.

    Good Luck.....
     
    #7 BiomedO1, Dec 8, 2025 at 11:31 AM
  8. DirkAshburn

    DirkAshburn Member

    Joined:
    Apr 6, 2020
    147
    61
    1
    Location:
    Virginia
    Vehicle:
    2011 Prius
    Model:
    Four
    #8 DirkAshburn, Dec 8, 2025 at 12:28 PM
    ericbecky, bisco and Brian1954 like this.
  9. spgview211

    spgview211 New Member

    Joined:
    Sunday
    6
    1
    0
    Location:
    Bay Area,Ca
    Vehicle:
    2010 Prius
    Model:
    Four
    Thank you. Might have been a downgrade, based on the chemist
    It appears I found 14.4V 6.5ah ,
     

    Attached Files:

    #9 spgview211, Dec 8, 2025 at 12:59 PM
  10. spgview211

    spgview211 New Member

    Joined:
    Sunday
    6
    1
    0
    Location:
    Bay Area,Ca
    Vehicle:
    2010 Prius
    Model:
    Four
    Tempted to go the used route with a JDM battery and buy the Prolong battery charger to fully charge or balance the pack prior to install, if I can’t get this functional in a week or two.

    OEM more than likely has better chemistry than these cells, to your point maybe it’s a downgrade and not an upgrade….
     
    #10 spgview211, Dec 8, 2025 at 1:03 PM
  11. PriusCamper

    PriusCamper Senior Member

    Joined:
    Mar 3, 2012
    12,755
    5,163
    0
    Location:
    Pacific Northwest, USA
    Vehicle:
    2007 Prius
    Model:
    Two
    JDM wouldn't be wise when battery cores can be had for only $200... And if you want to have a rebuilt pack on the shelf and one in the car that could work, but its a steep learning curve to rebuild packs well and with each rebuild it becomes less viable. Even the best rebuilders can onlymake money on 3-year warranties. Of course if you get good at finding packs for cheap and enjoy the rebuilding process you can make money helping out friends and family.

    I ended up with lots of spare OEM packs thanks to being an installer of Sodium-Ion packs... I usually sell them to rebuilders but always have a spare lying around.

    As with all things, the more involved you get with stuff like this, the more opportunities arise at a great price. But if you have a spare couple thousand bucks, just get something new and forget about it and don't bother with rebuild learnings.
     
    #11 PriusCamper, Dec 8, 2025 at 9:33 PM
(You must log in or sign up to post here.)