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Auxiliary battery not charging - Good battery

Discussion in 'Generation 1 Prius Discussion' started by Wecandothat4u, Feb 18, 2020.

  1. Wecandothat4u

    Wecandothat4u Junior Member

    Joined:
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    Location:
    Cambridge, MN
    Vehicle:
    2006 Prius
    Model:
    Base
    Just picked up a third Prius from a salvage guy. This one a 2002. Tossed in the good HV battery (which I reconditioned) from my now parts car.

    Also installed a new (used) auxiliary Toyota AGM battery that load tests good, was fully charged and everything worked fine. Lots of warning lights were on so I cleared the codes, was testing the heater (it's 8 degrees out there now) and finding out what else was working or not. It ran for a while... five-ten minutes and the Aux. battery became too low to maintain the heater, the Multi Display screen was jumping. Shut off the heater and the display settled down but then a little while later we just ran out of 12V and the engine quit. Screens darkish.

    Only two codes:
    C1215 Low Power Supply Voltage in Linear Solenoid
    B0101, an Airbag Code ISO/SAE Reserved.

    C1215 says Battery, Charging system or Power source circuit.
    I can't find B0101 in the manual.

    I have been unable to find anything relating to charging the Aux Battery.

    Any guidance will be appreciated.
     
    #1 Wecandothat4u, Feb 18, 2020
  2. Wecandothat4u

    Wecandothat4u Junior Member

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    Base
    More simply said. Can anyone help me find out how the auxiliary battery is charged and how to troubleshoot the circuit?

    I have the Shop Manual so even pointing me where to go in the manual would help a lot.
     
    #2 Wecandothat4u, Feb 24, 2020
  3. Priuslover09

    Priuslover09 Member

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    It’s not normal for it not to charge? What happened?
     
    #3 Priuslover09, Feb 27, 2020
  4. ChapmanF

    ChapmanF Senior Member

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    Vehicle:
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    Model:
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    Charging happens because the DC/DC converter (located inside the inverter assembly) produces a voltage slightly higher than the 12 volt battery (in a Gen 1, a voltage around 13.8), so whenever the converter is operating, current is flowing backward through the battery, charging it.

    With a voltmeter, you can quickly confirm whether there is or isn't about 13.8 volts available while the car is in READY. If it isn't (anywhere), the converter isn't functioning for some reason. If you can measure 13.8ish in some places, but not at the battery, while in READY, there may be a fuse or connection open somewhere.

    They don't offer component-level repair info for the converter; if it doesn't work, their idea is to replace it.

    Same place the shop manual came from, there is the New Car Features manual, which has the basic system overviews and explanations that you're not finding in the shop manual itself, and also the Electrical Wiring Diagram manual, which has those kinds of details.
     
    #4 ChapmanF, Feb 27, 2020
    H4rmonthomas, mroberds and zpi28 like this.
  5. Wecandothat4u

    Wecandothat4u Junior Member

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    Vehicle:
    2006 Prius
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    Base
    I picked the car up cheap from a wrecker type guy. Missing HV battery and 12V battery. I cycled and cleaned and tested my old HV battery from my dead 2003, bought a 12V battery and started troubleshooting.
     
    #5 Wecandothat4u, Mar 6, 2020
  6. Wecandothat4u

    Wecandothat4u Junior Member

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    Thanks for this info. I'll look for the New Car Features manual.

    Yup, there was no 13.8ish anywhere and the wiring diagram told me the harness and fuse were okay. So I swapped out the Inverter/Converter and it now works. Woohoo! Again, it's nice to have a spare parts vehicle sitting here.

    Thanks for the help. I still have a few codes. In fact, a bunch of warning lights just came on right now. I'll go mess with that and be back after a bit.
     
    #6 Wecandothat4u, Mar 6, 2020
    mroberds likes this.
  7. Q*bertZ

    Q*bertZ Member

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    2002 Prius
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    So what happened? I've got a similar problem.
     
    #7 Q*bertZ, May 17, 2022
  8. ChapmanF

    ChapmanF Senior Member

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    As you can see in the post immediately above yours, the OP was able to confirm there was no 13.8ish voltage present when the car was READY, meaning the converter wasn't working, so the OP replaced the inverter/converter assembly and that solved the problem for the OP.

    If you're having a "similar" problem, you will likely be best served by following the same kind of diagnostic steps as the OP, rather than trying to go straight to the same fix as the OP. The diagnostic work will tell you whether the cause in your case is the same or something different, and if it's something different, that's what you'll want to fix.
     
    #8 ChapmanF, May 18, 2022
  9. Q*bertZ

    Q*bertZ Member

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    I was referring to his very last statement...

    In fact, a bunch of warning lights just came on right now. I'll go mess with that and be back after a bit.

    Here said he would "be back after a bit"
     
    #9 Q*bertZ, May 18, 2022
  10. Q*bertZ

    Q*bertZ Member

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    I figured it out. I had a donor invertor and replaced all the upper components. MG1 and MG2s components. Not knowing the the dc convertor is on the bottom of the invertor. I couldn't use the donor invertor because all the cover bolts broke off and wouldn't seal if I used the case. The connectors and gold casing by the yellow arrow is the 12 volt (13.8) supply. I'm glad it's over 20220518_190351.jpg
     
    #10 Q*bertZ, May 18, 2022
  11. ChapmanF

    ChapmanF Senior Member

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    (y)
     
    #11 ChapmanF, May 19, 2022
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