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Drained my HV/Traction battery to 1 bar in neutral by accident while parked

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by h1ph0panonymous, Jul 3, 2024.

  1. h1ph0panonymous

    h1ph0panonymous Junior Member

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    2014 Prius
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    Four
    Title mostly says it but I also went over a muddy trail before and after doing said stupid thing in neutral/idle while accessories were on (AC/Medium Fan).

    Gave me the info message saying car won’t charge in neutral and noticed it was at 1 bar when it happened, put it in park immediately and let it recharge the battery.

    Symptoms after that are as follows:

    Sluggish/Slippish lift offs from red lights.

    ICE will kick back on after car does it warm up on start after reaching 100 degrees and will continue to stay on, water temperature reached 205 degrees on my ScanGauge || reader because the ICE continued to run while I was in some small town lake front July 3rd with traffic going a snails pace due to firework events, was stressing the whole time because usually kicks into EV mode when going a snails pace, nope, ICE was still running since it started up from park 10 minutes ago from the beginning of the drive.

    12v Battery reads @ 14.1-14.0 volts when the car is driving, parked and or idling, nothing changes this voltage reading. Used to be another number before this incident, 15ish volts in normal.

    EV mode finally kicked in when traction battery was at 1 bar AWAY from FULL bars, so like 15 minutes of driving is when it finally kicked in and started acting the ways it’s suppose to.

    Did I hurt the 12volt battery? Is ice constantly running to maintain and charge a new imbalance it incurred with said situation between the charging the traction battery does for the 12 volt when 12volt battery needs to be charged? Is this imbalance able to be rebalanced by over charging the traction battery down a hill so it hits actual full bars?

    Just took a pressure washer to the underbody of the car to get rid of that mud which was covering up everything.

    Going to over charge the traction battery down some hills and see if it fixes the imbalance otherwise I’m assuming I will need to trickle charge the 12volt back to its normal self.
     
  2. Brian1954

    Brian1954 Active Member

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    What year is your Prius, and how many miles?

    I think you are being a little paranoid. The car is fine (both the HV battery and 12v battery). The car will keep the HV battery between 40 and 80% state of charge as long as you are not in neutral. Yes, you could charge the 12v battery if you are concerned with its state of charge.

    Just drive the car like you normally do.
     
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  3. Mendel Leisk

    Mendel Leisk Senior Member

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    How many bars of charge is hybrid battery showing now. I would think if it’s back over two you’re out of the woods. You could try Dr Prius app too, see what it shows. It needs a Bluetooth dongle on OBD port; Carista works. Attached static test will give you some idea without a lot of hassle.
     

    Attached Files:

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  4. ChapmanF

    ChapmanF Senior Member

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    What you essentially did, without intending to, is a lot like the "confirmation driving pattern" for the P0A80 code, where the car tests how well the battery holds up under a deep discharge. And you did that and the car has not set that code, so it seems you've been given a pretty clean bill of health. Go and sin no more.
     
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  5. h1ph0panonymous

    h1ph0panonymous Junior Member

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    2014 Prius
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    Four

    Everything went back to normal the night I pressure washed the underbody and over charged it beyond 8 bars of HV battery.
     
  6. h1ph0panonymous

    h1ph0panonymous Junior Member

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    Yeah symptoms went away after a long drive to work down some hills on top of pressure washing the underbody. Pretty sure it was over charging downhill that corrected it unless the mud I washed off was interfering with something.
     
  7. h1ph0panonymous

    h1ph0panonymous Junior Member

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    I think the 12volt battery took a hit more than anything because symptoms went away after a long drive to work down some hills that I was able to over charge the HV battery on.

    weird but all good now, thanks for the input guys.
     
    Mendel Leisk likes this.