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Prolong Charger - Voltage Decreasing

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by JMJCATH, Jun 17, 2018.

  1. JMJCATH

    JMJCATH Member

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    Has anyone else experienced their voltage going down while using the Prolong charger?

    I am in the process of charging the battery. After charging for 20hours, the voltage was at 238v and then at the 24 hour mark, it went down to 235v . The hybrid battery fan is running, ambient temperature is around 85 degrees, and the amps appear to be constant. No associated discharge was done at this time; only a hybrid battery charge. Anybody?
     
    #1 JMJCATH, Jun 17, 2018
  2. SFO

    SFO Senior Member

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    Yes, but I had a different situation and ambient conditions.

    You might give it some more time and see if it balances upwards again.

    Otherwise jump into the first discharge cycle, and play catch up on the next (or final) charge/balance cycle.

    How many miles on the HV battery?
     
    #2 SFO, Jun 17, 2018
  3. JMJCATH

    JMJCATH Member

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    It's on a 2012 V with 40K miles. I've discharged it twice and charged it about 6 times. Unfortunately, I can't discharge it right now since I need the car until July.
     
    #3 JMJCATH, Jun 17, 2018
  4. SFO

    SFO Senior Member

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    Seems a little early in your batteries life for a single reconditioning, much less multiple times :confused:

    Why do you feel the need to continually recondition a relatively new battery with only 40k miles, did something happen?
     
    #4 SFO, Jun 18, 2018
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  5. fotomoto

    fotomoto Senior Member

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    OP only has 40k miles; that's about a 5k/yr average which is not good for HV battery longevity. BTDT Agree about the number of sessions, probably should ask prolong for guidance.

    On the voltage concerns, from the prolong website: "During the 'balancing' phase you will most likely see a steady voltage reading or a very slow oscillation of voltage - perhaps a 1-3 volt swing over several minutes. This means the battery is in the balancing phase".
     
    #5 fotomoto, Jun 18, 2018
  6. JMJCATH

    JMJCATH Member

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    Because of Prolong's advice, found in their FAQ's, "Even if one were to have to eventually replace part or all of the hybrid battery, a Prolong Battery Reconditioning Package is still a good investment as it will prevent the replacement hybrid battery from returning to the deteriorated state of the current pack. We have many customers that are buying brand new hybrid battery packs and adding a Prolong Battery Charger on day one to eliminate the chance of cell imbalance returning."

     
    #6 JMJCATH, Jun 18, 2018
  7. JMJCATH

    JMJCATH Member

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    The voltage wasn't oscillating at all, nor was it oscillating over several minutes. It was continuously going down.

     
    #7 JMJCATH, Jun 18, 2018
  8. JMJCATH

    JMJCATH Member

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    #8 JMJCATH, Jun 18, 2018
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  9. fotomoto

    fotomoto Senior Member

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    Ahh. I'd say then it's time to stop if you've been at it for 24+ hours. My guess is it's just a temperature thing as my peak voltages were consistently lower during warmer months. Check with jeff and report back please.
     
    #9 fotomoto, Jun 18, 2018
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  10. taxibuddy

    taxibuddy Member

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    Is this a Toyota battery with a Toyota warranty?
     
    #10 taxibuddy, Jun 18, 2018
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  11. Joeman200

    Joeman200 Junior Member

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    Resurrecting this old thread instead of starting a new one. I'm having the same issue. I was in stage 2, dropped to 101 volts and started to recharge. Gained the first part back in decent time, then took around 24 hours to go from 230 to 242volts. Over the past 4 hours, my voltage has now slowly been dropping to 235volts. Thoughts? I may just start my discharge cycle.
     
    #11 Joeman200, Oct 3, 2023
  12. SFO

    SFO Senior Member

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    Best to start your discharge (after a cool down), as the instructions mention not to charge for over 24hrs (unless that has changed).
     
    #12 SFO, Oct 6, 2023
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