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Gen 1 2001 Prius: HV battery issues

Discussion in 'Generation 1 Prius Discussion' started by Moazim, May 25, 2020.

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  1. Moazim

    Moazim New Member

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    Hi folks,

    Sorry if I use the wrong terminology. Its the 1st time doing something like this.

    I'm trying to fix my mum's HV battery in her 2001-2 gen 1 Prius. The car had been stationary for a while so the HV battery is dead. I've gotten as far as removing it and checking the voltage and the majority of the cells have little to no charge (between 0.1 - 5v). My dilemma is:
    1. Should I replace the whole battery (£350 - £400)? Or,
    2. Balance charge each cell? (I've got the time to do this)
    Is it possible to fully charge each cell even if the voltage is very low? I'm trying to do this in the most cost effective way and time is not an issue.

    Thanks in advance,

    Mo :)
     
    #1 Moazim, May 25, 2020
    Bruce Berquist likes this.
  2. Nelsonprius

    Nelsonprius Junior Member

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    I'd balance charge each module, load test each module and replace those that drop voltage significantly under load, or too quickly lose power compared to the others. Reconditioned modules can be bought online.
    Discharge and recharge all modules 3 times to same levels, and pack should be good to go.
     
    #2 Nelsonprius, May 25, 2020
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  3. Bruce Berquist

    Bruce Berquist Junior Member

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    If you have the time I recommend doing it DIY (don't get soaked for replacing things that don't need replacing and are serviceable).

    Yes it is possible to charge each cell, but make certain that you don't charge then individually outside of the assemble. in other words, keep the cells in the assembly.
    As they charge and discharge they build up heat and pressure so it is important that the cells stay compressed together as a pack. Otherwise they will expand and can be damaged or even explode when not in the pack.
    Then balance all of the cells to within spec.
    What cells that won't balance, or lose specified voltage after balance will need to be replaced.
     
    #3 Bruce Berquist, Mar 26, 2023
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