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.

  1. spgview211

    spgview211 New Member

    Joined:
    Yesterday
    3
    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.
     
  2. spgview211

    spgview211 New Member

    Joined:
    Yesterday
    3
    1
    0
    Location:
    Bay Area,Ca
    Vehicle:
    2010 Prius
    Model:
    Four
    +photos
     

    Attached Files:

  3. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    113,985
    51,906
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    indel likes this.
  4. spgview211

    spgview211 New Member

    Joined:
    Yesterday
    3
    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:

    bisco likes this.
  5. indel

    indel Member

    Joined:
    Apr 1, 2024
    92
    32
    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.
     
  6. BiomedO1

    BiomedO1 Senior Member

    Joined:
    Mar 27, 2021
    3,590
    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. DirkAshburn

    DirkAshburn Member

    Joined:
    Apr 6, 2020
    147
    60
    1
    Location:
    Virginia
    Vehicle:
    2011 Prius
    Model:
    Four