Ohmmu LFP battery in a Gen 5 Prius ?

Discussion in 'Gen 5 Prius Technical Discussion' started by RandyPete, Nov 10, 2024.

  1. Isaac Zachary

    Isaac Zachary Senior Member

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    Update with the LiTime battery:

    We hit some serious cold here, down to the negative thirties for a couple weeks straight. What I learned is if I shut off the car for about 8 hours, running it just before getting into bed and then just as I got out (and yes, running out there at -35 °F in my pajamas) and turned on the car, the battery would hold enough heat to not shut down completely even at those very cold temps.

    At around -10 °F to -15 °F it seems kind of hard to get it down cold enough to get it to shut off with driving the car home at around 4 or 5pm the previous day and getting in and starting up at around 6 to 9am the next. Only if you leave it off all day and all night does it become a problem at those temps.

    If it's just going to dip down to -4 °F or -5 °F or so in the morning, it's seemingly impossible for the battery itself to get that cold and shut off.

    • So all in all, if it's getting down to -10 °F to -20 °F, then I make sure I'm driving the car at some point the afternoon before.
    • If it gets down from -20 °F to -35 °F, then it's important to do something like run the car before bed and after getting up, because when you don't then you're going to have to jump start the car with another battery, which also seems to work too, it just resets all your car's computer stuff.
     
  2. vvillovv

    vvillovv Senior Member

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    Have you tried a trickle charger to see if that will kick on the batteries heater while the Avalon is sleeping?
    Do the specs say what kinda charge the heater needs before it switches on?
    It's a balmy 17 F today and I keep the Prime plugged in a LOT to keep those traction heaters on alert.
     
  3. RandyPete

    RandyPete Active Member

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    Car parked outside or in garage ?
     
  4. Gokhan

    Gokhan Senior Member

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    So, an LFP 12-V battery doesn’t really work in cold? Great.
     
  5. Isaac Zachary

    Isaac Zachary Senior Member

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    Outside.
    If you live where it gets down to negative 20 °F and below, you park outside all night and you're not willing to do something about it, no.
     
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  6. RandyPete

    RandyPete Active Member

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    ?? Don't understand your reply.
     
  7. Isaac Zachary

    Isaac Zachary Senior Member

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    You asked if I park outside. I don't have a garage, so yes, I park outside, all night long. So yes, I was able to get the car through the night outside with it as cold as -35 °F and the car still started the next morning. All I needed to do was run the car half an hour before bedtime and then go out and start the car early. An appropriate battery charger would also keep this self-heating battery warm all night.

    @Gokhan indicated that LFP batteries won't work in the cold. But as I've demonstrated, they work just fine down to around -15 °F. So if you don't get down past that, you'll probably never have any problems.
     
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  8. RandyPete

    RandyPete Active Member

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    Ask a simple question, got a thorough in depth answer. Thank You !
     
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  9. RandyPete

    RandyPete Active Member

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  10. Isaac Zachary

    Isaac Zachary Senior Member

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    This one: LiTime 12V 100Ah Self Heating LiFePO4 Lithium Battery – LiTime-US, but no, it does not fit in the stock battery holder. Mine is wired to be in the trunk. I'm not sure of the dimentions of the stock battery, but LiTime does have a newer self-heated battery that is smaller, group 24 sized battery that might fit, although I have my doubts.
     
  11. RandyPete

    RandyPete Active Member

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    Yea, that's the battery I linked above.
    LiTime
    Group 24 size
    Self heating
    Blue tooth
    100 AH
    And if I remember correctly, your vehicle is not a gen5 Prius but an Avalon.
     
    #51 RandyPete, Feb 1, 2025 at 7:34 PM
    Last edited: Feb 1, 2025 at 7:41 PM
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