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Low traction battery - is this normal??

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by PriusRos, Sep 6, 2013.

  1. PriusRos

    PriusRos A Fairly Senior Member - 2016 Prius Owner

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    A little while after I first got my Gen III Prius I posted a thread in this forum about the traction battery going down to one bar in the pull-through car wash when in neutral and beeping at me furiously. I thought it may have been a one-time thing because I was low when I went it, but since then it has happened to me a number of time.

    The last time, I checked the battery display before I entered the car wash and it was at around 6 bars. There was no line - - all I did was slow down to pay and then drive slowly into the car wash. By the time I had to shift to neutral, it had dropped to around 3 bars. About half way through, it dropped down to 1 bar and started beeping at me loudly. This is most disconcerting. I had made sure everything - AC, stereo, etc. -- was off before I entered the car wash.

    Is this normal? today I went to the dealer for the brake recall issue. While I was there, I mentioned the battery issue. Basically they told me that there isn't anything they can do about it because that's the way it's designed.

    Shouldn't the traction battery hold a charge for more than 5 minutes while in neutral? And why is it dropping so much when I slow down? I cannot find a way of forcing it to charge. I've tried pressing the brake and putting it in park and pressing the gas - but nothing happens.
     
    #1 PriusRos, Sep 6, 2013
  2. bisco

    bisco cookie crumbler

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    does your '06 do the same thing?
     
    #2 bisco, Sep 6, 2013
  3. jdcollins5

    jdcollins5 Senior Member

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    The HV battery is disconnected while in neutral so it cannot get recharged. Also when you are slowing down and creeping up to the car wash you are running in EV which will drain the battery quickly.
     
    #3 jdcollins5, Sep 6, 2013
  4. Mendel Leisk

    Mendel Leisk Senior Member

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    The Prius with it's inability to be shutdown in Neutral, is problematic in carwashes. I think it's pretty much unique in this regard. Maybe the Camry and Highlander Hybrids are in the same boat. Anyway, between the Neutral factor and the countless negatives about automated car washes, I'd just avoid them, LOL.
     
    #4 Mendel Leisk, Sep 6, 2013
  5. bisco

    bisco cookie crumbler

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    i never thought about it, but my wife has never had a problem in her hycam. bigger battery i suppose.
     
    #5 bisco, Sep 6, 2013
  6. rdgrimes

    rdgrimes Senior Member

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    Can't you shut the hybrid system off and use "on" mode to put it in neutral? Then its only draining the 12v batt.
     
    #6 rdgrimes, Sep 6, 2013
  7. vincent1449p

    vincent1449p Active Member

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    The HV battery is only disconnected in Ready-Off, not in neutral. It cannot get recharged in neutral because both MG1 and MG2 are turned off by the inverters. Either one must be turned on to charge/discharge the HV battery.

    As long as the car is in Ready-On, the DC-DC converter will continue to draw power from the HV battery to supply to the 12V loads even in neutral. You can try what rdgrimes suggested.

    Vincent
     
    #7 vincent1449p, Sep 7, 2013
  8. PriusRos

    PriusRos A Fairly Senior Member - 2016 Prius Owner

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    Thanks for all the replies. No, it did not happen with the '06.

    I don't understand how you can turn off the hybrid. Do you mean power off then power on without holding the brake?
     
    #8 PriusRos, Sep 7, 2013
  9. PriusRos

    PriusRos A Fairly Senior Member - 2016 Prius Owner

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    How Long will it last without charging aanyway?
     
    #9 PriusRos, Sep 7, 2013
  10. vincent1449p

    vincent1449p Active Member

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    Yup.

    It depends on a lot of factors. Do you have any instrumentation to monitor the SOC, HV battery current, Aux. battery voltage, etc? e.g. ScangaugeII, Torque, Techstream, etc.

    Vincent
     
    #10 vincent1449p, Sep 7, 2013
  11. PriusRos

    PriusRos A Fairly Senior Member - 2016 Prius Owner

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    No, I don't have any instrumentation like that.

    Another thing -- I really don't understand why it would be discharging while going through the carwash in neutral. I understand that it isn't charging -- but why is it discharging when it's not going anywhere? I think I turned everything off -- the only thing is that I might have left my lights on by mistake. This afternoon I ran an experiment in my driveway. I put it in neutral and applied the emergency brake. The battery was on three bars. I sat there with the AC, lights, and stereo on for several minutes. The battery went down to two bars but remained there. I guess I didn't wait long enough but it never got to the one-bar beeping stage. I'm not sure how long the carwash is but I don't think it's more than 5 minutes, although it feels like an eternity when the thing is beeping at me!!

    If the 12V battery is low, is there a chance that the traction battery is discharging because it's charging the 12V?
     
    #11 PriusRos, Sep 7, 2013
  12. vincent1449p

    vincent1449p Active Member

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    The hybrid has 2 power source; engine and HV battery. If the engine is turned off, where do you think the power has to come from?

    Even if you turned everything off, the HV battery is still draining because all the ECUs need power, the power steering motor needs power, the brake booster pump needs power and many more electronics need power. I 've SGII and I can see how much current is being consumed if I turned on the headlights for. e.g.

    Without instrumentation, I have no clues what cause the differences in both situation.

    Possible. Then again, without instrumentation, we can only guess.

    In Ready-On, the DC-DC converter is always charging the Aux. battery. On my c, it is always 14.2V at the start of the journey and drops to 13.4V after 30 mins. or so.

    Vincent
     
    #12 vincent1449p, Sep 8, 2013
  13. PriusRos

    PriusRos A Fairly Senior Member - 2016 Prius Owner

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    Thanks, Vincent. My point is, why does it need any power if the only thing that's happening is that the wheels are turning on the little rail thing to pull it through? I'm not using power steering or the brake and I think I had turned off all electronics although I might have left the lights on. No fan, AC, or stereo. In any case, aren't the lights powered by the 12V battery?

    So, do no other Prius owners go through the automatic carwash?
     
    #13 PriusRos, Sep 8, 2013
  14. Jeffrey Jessup

    Jeffrey Jessup Member

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    Just getting ready to give mine a hand wash tomorrow to remove some tree sap and apply some wax while the paint is still new looking. After reading this post, I think I'll stay clear of the car wash I used to use in the winter when I didn't want to drag the hose out. Would like to hear what other owners, that have had their cars longer, have to say about their experience with these kind of car washes.
     
    #14 Jeffrey Jessup, Sep 8, 2013
  15. jdcollins5

    jdcollins5 Senior Member

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    I go through automatic touchless carwashes from time to time in the middle of the week to remove road grime after a rain but I go through the type where the car is stationary and the washer moves around the car. This way I can keep the car in park with the AC on and the ICE will start if necessary.

    I understand your question about the drain on the battery during the carwash. I can sit in park with the AC on and the wash is complete well before the SOC drops to the point that the ICE needs to run.
     
    #15 jdcollins5, Sep 9, 2013
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