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About hybrid battery current limits

Discussion in 'Gen 3 Prius Technical Discussion' started by burebista, Aug 7, 2023.

  1. burebista

    burebista Active Member

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    I monitor my car every week when I go to my brother in law for a barbecue. :D
    It's a short 20 miles trip on a straight road.
    Usually fuel consumption is around 58 MPG and battery looks like this.

    hb good.jpg

    But yesterday when I come home that graph looks a "little" bit different.

    hb wonky.jpg

    It was a hot day, car sits all day in sun at 35°C (95°F) and at start hybrid battery has 56°C (133°F) going down to 46°C (114°F) at the end of the trip.
    Engine was acting different too, even if battery was almost full sometimes it still rotate with foot off of the gas.
    Fuel consumption drops to 48 MPG too.
    Below a graph with all temps during that trip.

    temps.jpg

    I know that my hybrid battery is dying but it's first time for me when I saw this behavior and I'm curious if it's normal. I know that charge/discharge current limit depend on ambient temperature so I guess (hope) that's a normal behavior.
     
    #1 burebista, Aug 7, 2023
  2. Tombukt2

    Tombukt2 Senior Member

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    If your battery's dying then it's out of spec in the behavior is well not so normal I would think. But I don't know how much better it will be with a brand new battery at 120 or 100 and whatever degrees you said have no clue but I imagine with everything else in the 21 or 24 computers that are in these cars It has a heat management system so it's going to throttle back and do things to keep the battery inverter and other things from getting too hot overheating what have you whether that means the car has to drive real slow or park or whatever well such as life I guess and this is what happens with electronics and heat. So I guess that's why these electric cars and what have you have to have a lot of things going on because they need cooling just about as bad as an ice engine.
     
    #2 Tombukt2, Aug 7, 2023
    burebista likes this.
  3. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    It looks like battery participation was limited until battery temp dropped below 50°C

    Couldn't tell you if that's normal or not.
     
    #3 Leadfoot J. McCoalroller, Aug 7, 2023
    CR94 and burebista like this.
  4. ChapmanF

    ChapmanF Senior Member

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    I guess it wouldn't surprise me at all that the current limits would be kept conservative until the battery gets to a better temperature.

    Gen 1 even had a yellow turtle light on the dash that would come on if the battery temperature got high enough and the current was considerably cut back.
     
    #4 ChapmanF, Aug 7, 2023
    CR94 and burebista like this.
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