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How to calculate mAh capacity of a single module

Discussion in 'Gen 2 Prius Main Forum' started by rogerdpack, Sep 17, 2024 at 4:56 PM.

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  1. rogerdpack

    rogerdpack Junior Member

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    Enoch, UT
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    2007 Prius
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    There are modules for sale on (ex: ebay) that say "4K mAh capacity" or what have you. I tried to ask people how they calculated that and they seem to say "we put it on the charger, cycle it, and the charger reports this capacity number" LOL. So...how is this number calculated by chargers, anybody's guess? Do they max out voltage then run it down to a certain voltage, and use that? Is there a common way to calculate it? Reason being is I want to buy one that kinda matches my current modules as a replacement (for a bad module) but not sure how to measure capacity of my modules to \see how they compare...

    Thank you :)
     
    #1 rogerdpack, Sep 17, 2024 at 4:56 PM
  2. PriusCamper

    PriusCamper Senior Member

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    Two
    Well... I always say the rebuilders that spend tens of thousands of dollars on lab grade electronic systems to measure cell capacity do it much more accurately and efficiently, and that hobby chargers and dischargers aren't very accurate because they can't be calibrated / fine tuned.

    But then @TMR-JWAP will come along and explain that he finds hobby chargers accurate enough and his methods seem fairly straightforward.

    If you're just trying to buy high quality used modules that aren't junk than buy from professor Joe. He not only has spent a fortune on battery rebuilding gear over the decades, but he teaches hyrbid and EV cars at the local college: Hybrid Car Battery Distributor | Contact Us | 2nd Life Battery
     
    #2 PriusCamper, Sep 17, 2024 at 8:21 PM
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