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LiFePO4 12v battery replacement?

Discussion in 'Gen 5 Prius Care, Maintenance and Troubleshooting' started by onthesalt, Apr 5, 2024.

  1. onthesalt

    onthesalt New Member

    Joined:
    Mar 25, 2024
    17
    18
    1
    Location:
    seattle, wa
    Vehicle:
    2024 Prius Prime
    Model:
    XSE Premium
    I know older generations of prius have successfully replaced the 12v with a lithium battery, but looking for experience with a 5th gen. LiFePO4 seems to be the best option due to fire resistance and higher cycle life. Biggest concern I have is that the BMS on a LiFePO4 will kick off while you're driving the car so it's got to be "big enough". I just got the car but given the 12v battery problems it seems like it may be a good option. I see this option 12V Lithium Battery for Toyota Prius | ohmmu.com for $265 but it doesn't give any specs to max current in/out or even capacity. Here's what I think is a better option - LFX19A4-BS12 for $220 it's a match at 285CCA and 19hr reserve and you can get bigger capacity which is great for a parking mode dashcam or big stereo. BUT (and it's a big BUT) I looked at the manual and it says "Do not allow discharge below 13.0V (resting 13.0V for 12V LFX, 6.5V for 6V types )" which my experiments with the Prius Prime '24 show violate this. I posted in page 7 of Third day with new car, dead 12V battery, second day in a row :( | PriusChat showing that the car always lets the 12v run down to 60% which is in the low 12V range before it will charge it.
     
  2. DOHCtor

    DOHCtor Member

    Joined:
    Aug 19, 2021
    130
    74
    0
    Location:
    Levis (Quebec city's south shore)
    Vehicle:
    2024 Prius Prime
    Model:
    SE
    I tought about that. I can have a Noco Lithium battery for a relatively low price and it could shed about 30pounds off the car.. maybe someday when the replacement battery i have in finally dies..