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Gen I 12V battery charging

Discussion in 'Newbie Forum' started by flynham, Dec 16, 2010.

  1. flynham

    flynham New Member

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    I just purchased this 2001 Prius. The hybrid battery pack was totally discharged. I replaced the battery pack along with several fuses. The car started and ran fine. After a day or so I started the car and drove it a few miles. As I was driving, "check engine" display came one. Shortly thereafter, at a stop, the car "died". After some checking, I put a booster on the 12V battery and drove it home. As I was driving it the "check engine" display was still on. What should I look for to determine the problem with this car?
     
    #1 flynham, Dec 16, 2010
  2. drew_flux

    drew_flux Junior Member

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    it sounds like your aux battery is not holding charge.however there may be other issues going on. i would 1. loadtest/charge the 12v battery.if thats ok then 2.check the charge rate coming from the inverter.put a voltmeter across the aux battery with ready on, you should have 13-13.8v on the meter.
     
    #2 drew_flux, Dec 16, 2010
  3. drew_flux

    drew_flux Junior Member

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    oh just remembered when chargeing the aux battery with a charger. do not let the charge current rise above 4.5 amps.
     
    #3 drew_flux, Dec 16, 2010
  4. flynham

    flynham New Member

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    Thanks a bunch. I will try that tomorrow to see what happens. Have
    the 12V battery on trickle (2 amp) charge right now so should be good
    tomorrow. If the voltage from the inverter is not as you mentioned,
    does this mean the inverter is malfunctioning?
     
    #4 flynham, Dec 16, 2010
  5. flynham

    flynham New Member

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    Checked the voltage this morning and it is showing 12.12V with the "ready" on. Could anyone tell me where to go from here? From what I understand, the 12V battery is NOT being charged from the inverter. Does this mean the inverter is bad or is there something other than the inverter that would cause this problem? Thanks
     
    #5 flynham, Dec 17, 2010
  6. drew_flux

    drew_flux Junior Member

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    I just realized that you had a gen 1,i was thinking you had gen 2, i may have given you some bad info, will look in to the charging system on gen 1 on Monday. i seem to remember the gen 1 having a normal starter motor, now I'm wondering if gen 1 has a normal alternator as well and i have just forgotten.its been a while since i worked on one.
     
    #6 drew_flux, Dec 17, 2010
  7. flynham

    flynham New Member

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    Thanks much! I'll be waiting to hear from you....
     
    #7 flynham, Dec 18, 2010
  8. drew_flux

    drew_flux Junior Member

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    thinking a bit more clearly today. don't know where i got the idea the was a normal starter motor on a gen 1. must be time to stop forum surfing late at night lol . Gen 1 prius definitely charges to aux battery through the inverter's dc-dc converter. been through the repair manual for nhw11, this morning, still can not find a spec for the charge rate.can only give you the numbers that i can test on vehicles coming through the work shop. your reading of 12.2 still seem a bit low when compaired to other vehicles, that have been coming through the workshop. i wonder if your 12v battery is any good.have your had it load tested?
     
    #8 drew_flux, Dec 19, 2010
  9. flynham

    flynham New Member

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    Have not had it load tested. Will do that first think in the morning.
    It is a relatively new battery, but from past experience, that doesn't
    mean a whole lot. After I have it tested I will let you know what I
    come up with. Again, thanks so much for your help.
    Emmette
     
    #9 flynham, Dec 19, 2010
  10. flynham

    flynham New Member

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    12V battery checks good, so will search other areas....
     
    #10 flynham, Dec 20, 2010
  11. Patrick Wong

    Patrick Wong DIY Enthusiast

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    You are right, the DC/DC converter within the inverter is not working correctly, since the voltage should be ~13.8VDC when the Prius is READY.

    You may want to obtain the logged DTC to confirm that the inverter has failed.
     
    #11 Patrick Wong, Dec 20, 2010
  12. flynham

    flynham New Member

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    Eventually got a code which referred me to either the ECM or HV ECU. From all I can
    deduce, the HV ECU is malfunctioning but will be replacing it and the ECM just for good
    measure. Thanks so much to drew_flux and Patrick Wong for the help. Will get back with you to let you know the results as soon as I get both computers replaced.
     
    #12 flynham, Dec 21, 2010
  13. flynham

    flynham New Member

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    For anyone chasing this thread, the end result was that my ECM was faulty in the car.
    After changing it, everything worked fine with voltage to Aux battery now at 13.8 with the
    "Ready" light on. Hopefully this might help someone else that encounters the same problem.
     
    #13 flynham, Dec 24, 2010
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