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Hybrid battery troubleshooting...

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by lgyurka, Oct 7, 2020.

  1. lgyurka

    lgyurka New Member

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    I have recently bought a 2009 Prius with 58K miles. It is possible that it had been sitting unused for a while, just based on the low mileage. I have previously owned a 2008, with 180+k miles and with my driving habits I was getting 50-55 MPG in city traffic. This newer one gets 40 MPG at its best, shortly after taking off from red lights the gasoline engine kicks in, and the car does not have a bite, like the 2008 did when accelerating.
    With Techstream I performed a detailed hybrid battery check with charging and under load and the results came back showing that the minimum battery pack voltage was 15.61V the maximum battery pack voltage was 15.67V. So far looks good, I did not have any trouble The State of Charge(SOC) varied between 54% and 47%. I don't experience sudden increase or decrease in the number of bars indicating charge, and it hold charge steady for days. While driving sometimes it goes all the way up to green bars, but I was not testing SOC at that time... Anyone has any pointers why the gasoline engine seems to dominate?
     
    #1 lgyurka, Oct 7, 2020
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  2. dolj

    dolj Senior Member

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    It sounds like this car may respond well to a round of conditioning with the Hybrid Automotive Prolong charger/discharger system.

    With all the sitting around, it sounds like the battery has developed a memory that is locking out some of its usable range.
     
    #2 dolj, Oct 8, 2020
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  3. SFO

    SFO Senior Member

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    #3 SFO, Oct 8, 2020
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  4. Aaron Vitolins

    Aaron Vitolins Senior Member

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    that’s what my first thought was too!

    In my experience, a old traction battery that NiMH that hasn’t been used much needs a good exercising. I had a Prius battery with high miles 200+k that had been sitting for some time. After cleaning the car up, fixing a few things, I noticed it seemed to be lacking the torque, and pep off the line. So I just drove it and drove it, trying to get as much regen on downhills as possible, drive around in all electric, and some full throttle runs.


    After really working that old battery out for a couple months it drives great, almost always stays at 6 bars, has good acceleration, and gets 50 mpg all day long.
     
    #4 Aaron Vitolins, Oct 8, 2020
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  5. Aaron Vitolins

    Aaron Vitolins Senior Member

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    Another thing I did was let the car sit in ready mode with the AC blasting, bringing the state of charge real low. From there I’d put it in reverse (with the engine already warmed up from driving) and floor it for a little bit. Bring the SOC very low.

    After that I put it in park and let it charge back up. It seems a little abusive to the battery, but I really do think it was good to exercise the old battery to bring the chemistry back to life.
     
    #5 Aaron Vitolins, Oct 8, 2020
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  6. dolj

    dolj Senior Member

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    "Another thing I did" after reconditioning your battery? Because that may be the only time when I might do that.

    Even so, I don't know if this is a good or a bad thing to do, but if anyone did feel inclined to do it, I'd advise a very gentle cautious approach - slow drain and slow charge.

    It will not do anything to balance (top or bottom) the hybrid vehicle(HV) battery, but it just may help with resetting the coulomb count, but then so will removing the 12 V power from the system.

    If a person's battery was already showing signs of weakness, this procedure may be just enough to tip the HV battery over the edge, so I wouldn't do it until after a balancing cycle. Do it at your own risk.
     
    #6 dolj, Oct 11, 2020
  7. Aaron Vitolins

    Aaron Vitolins Senior Member

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    yeah true! Definitely your own risk. I did this to revive a old battery that didn’t show many signs of degradation, more of lack of power vs fast low capacity or super unbalanced.

    Also, note that I did this after driving it a good bit for a month or two. I didn’t do this straight away after it was sitting for months.

    The battery is about 13 years old and has very very little voltage difference. Surprisingly good for its age I must admit
     
    #7 Aaron Vitolins, Oct 12, 2020
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