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Is my traction battery about to fail?

Discussion in 'Gen 3 Prius Main Forum' started by MattFL, Sep 11, 2019.

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  1. MattFL

    MattFL Member

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    I think I know the answer, but looking for experiences from someone who has had this issue. When it is hot outside (ambient in the 90's), the car acts like it does not want to use the traction battery. Sluggish acceleration, lots of revving, the motor runs more frequently and for longer periods when stopped, and just today the battery got down to the bottom two bars in normal traffic and it was a couple more miles of city driving plus several miles on the highway before it started to charge back up again. When it's cooler outside, say in the 80's, it seems to act more normal. Is this a sign of the battery getting ready to need some attention, or is this behavior normal when ambient temps are in the 90's? There are no warning messages (yet?).
     
    #1 MattFL, Sep 11, 2019
  2. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    You shouldn't anthropomorphize your car.
    They don't like it when people do that.....

    So....
    11 year old batteries are nearly always "about ready to fail"....especially in FL.
    It's probably not too early to start a battery replacement fund and start watching some Youtube vids on how to replace it.
    I've never done this myself but since I'm 'that guy' I've watched some vids on how it's done, and there's no way I'm paying this done.

    In a car that is as old as yours is I'd start sourcing a re-manned unit, but I would wait until you get more definitive symptoms before preparing the patient for surgery.....

    Good Luck!
     
    #2 ETC(SS), Sep 11, 2019
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  3. Grit

    Grit Senior Member

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    It's summer time so we get a lot of post similar to yours. The hv battery is in protection mode, it's too hot so it won't discharge or recharge. Happened to me before. Pull over and turn up your AC, let the HV fan take in the cool air. Once it cools down enough, hv battery will kick in like normal and then drive away. Some people are not doing that and are holding traffic back wondering why car isn't accelerating as much as it should.
     
    #3 Grit, Sep 11, 2019
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  4. bisco

    bisco cookie crumbler

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    the weaker it gets, the more it will protect, but there may still be a lot of life.

    how many miles on her?

    any change in mpg's?
     
    #4 bisco, Sep 12, 2019
  5. ASRDogman

    ASRDogman Senior Member

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    Depending on where you are in Florida, I wouldn't mind helping you out if you decide to replace the battery.
    It will be good experience!
     
    #5 ASRDogman, Sep 12, 2019
  6. TMR-JWAP

    TMR-JWAP Senior Member

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    One recommendation I would make, for those that don't have to worry about theft, is to purchase the plastic rain guards that mount in the windows. (like the weathertech ones). It allows you to keep the window cracked without rain getting in. This alone made a HUGE difference in how hot the interior of my car got this summer. I installed a set in early July, wow, what a difference.
     
    #6 TMR-JWAP, Sep 12, 2019
  7. bisco

    bisco cookie crumbler

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    consider a prolong charger reconditioner
     
    #7 bisco, Sep 12, 2019
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  8. MattFL

    MattFL Member

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    The car is actually a 2012, I know my profile still shows our old 2008 but I don't see a way to edit that info? This one has almost 70k miles and so far the mileage has not changed significantly yet. It seems the problem started this summer as I don't remember it being a problem last summer, though it has been a warm summer with most days and many nights in the 90's and the problem definitely happens in the heat.

    It's odd that the battery fan runs only when the car is moving (it's loud), but turns off when you stop even though the battery is apparently still hot. I'm sure Toyota does this for comfort reasons, but is there some way to have the fan run even when you're stopped if the battery is too hot?
     
    #8 MattFL, Sep 13, 2019
  9. ASRDogman

    ASRDogman Senior Member

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    Maybe the fan is clogged. Do you have dogs that ride in the car?
    It's not really hard to clean the HV battery fan.
     
    #9 ASRDogman, Sep 13, 2019
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  10. MattFL

    MattFL Member

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    Two small dogs that don't shed much and don't ride often. You can feel the fan sucking lots of air when it is running. I'm tempted to take the battery apart to see if maybe some of the cell terminals are corroded, maybe bad connection(s) are contributing to the issue?

    Does the battery fan in your cars run even when you're stopped, or only when you're moving? In my car you can hear it come on as soon as you start to accelerate, and for the first few mph it seems the fan speed is tied to the car speed, as if they don't want the fan running full blast until you're going fast enough for the road noise to partially cover it. I don't remember ever hearing the fan run when the car is stopped.
     
    #10 MattFL, Sep 13, 2019
  11. ASRDogman

    ASRDogman Senior Member

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    Ore you the original owner? If not, maybe the other owner had animals, or drove in a dusty area with
    the windows open.
    To get to the battery, you have to take apart the things to get to the fan, so start with the fan, then go to the battery
    if it's clean. I believe you can pull the cover off without removing the battery. Since I've not watched any videos
    lately I can't remember. But I'm sure someone will remember.
    I think in the Prolong video for installing the wiring harness for their charger/discharger they show just removing the
    top of the housing. So not too bad.
     
    #11 ASRDogman, Sep 13, 2019
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