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Dead 12v battery after installing a charger harness

Discussion in 'Gen 2 Prius Main Forum' started by Karah, Aug 7, 2018.

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  1. Karah

    Karah Junior Member

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    I bought a hybrid battery charger + harness from Hybrid Automotive. After installing the battery charger harness for my Prius 2006 & charging the battery w/o the car being on, but the 12v battery being reconnected as instructed, my cars engine would not turn on. The lights came on & the air from a/c came on, but did not run cool. The engine did not make its usual sounds. From reading info on my car, the 12v battery seemed to have un charged some... I did have it unconnected for about a full 24 hours...not sure if that did it?
    I had to go on an unexpected trip to aid family in a medical situation that involved travel & I was away from this vehicle for 10 days. About halfway through the trip, I had someone turn on the car & it had the same symptoms. When I returned, the car was dead. Nothing turned on.
    Please help me to understand what happened & if you have any advice, I will gladly take it. I followed the instructions correctly. I sent an email to the company, but didnt understand the point that was trying to be made. Something about the car door & lights will drain the 12v battery...but I had explained that when I charged the car with the new charger & harness, my car was not turned on, again as instructed through the installation guide posted online. They sent me a second email saying I could jump the battery, but it might just be weak. Go to a battery store to get more information they said. Any additional advice & info all would be greatly appreciated.
    Fyi, I'm looking into jumping the 12v battery. Please let me know if there might be something important to keep in mind regarding the system or a trick/strategy that make work to bring the car back to life.

    Thank you so much. I hope to have a healthy happy running Pruis with the new charger harness running smoothly soon.
     
    #1 Karah, Aug 7, 2018
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  2. PriusCamper

    PriusCamper Senior Member

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    Things start getting wacky with lots of strange anomalies when your 12volt battery is towards the end of it's life. Usually when I have to work on a hybrid battery the first thing I do is make sure the Hybrid battery cooling fan is clean and the 12 volt is new. Once that's out of the way, then I'll take a look at the hybrid battery pack. But you can't expect much success with hybrid pack work if you don't eliminate those other issues first.

    As for working with Prolong, I've found calling their customer service during business hours gets me in touch immediately with their tech support person 3 out of the 4 times I tried. They're super helpful....
     
    #2 PriusCamper, Aug 7, 2018
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  3. Karah

    Karah Junior Member

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    I read these codes after the red triangle & other lights came up on my dash. My EV specialist friend of the mechanic who still had me under warranty of this rebuilt hybrid battery (which now I read was the wrong thing to get) recommended the Prolong Charger. I was not able to check the fan when installing the harness; the clips were very tricky for me.
    With these codes, do you still think only the 12v was weakening?
     

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    #3 Karah, Aug 7, 2018
  4. PriusCamper

    PriusCamper Senior Member

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    A dirty fan can, or more rarely a bad 12 volt can trigger those codes... If your rebuilt hybrid pack is still under warranty, those error codes are exactly what you need to show them to get them to make good on their warranty.
     
    #4 PriusCamper, Aug 7, 2018
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  5. Karah

    Karah Junior Member

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    Thank you PriusCamper. My warranty ended this month & my mechanic had moved away much earlier. Only as a friendly gesture did he connect me with his friend who specializes in EV batteries. But that person has stopped responding to me.

    I am going to jump the 12v battery today. Can I charge it directly by connecting it to a battery charger? Also, I dont need to disconnect the 12v battery from the car when doing so right?

    Another symptom of late has been that the key fobs lose their ability to open the locked car doors & keyless starts. That is after I recently put new batteries in these fobs. Could that also be a sign of a weak 12v battery?
     
    #5 Karah, Aug 7, 2018
  6. PriusCamper

    PriusCamper Senior Member

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    For less than $10 you can buy a trickle charger that will top off the charge on your 12volt battery. Places like Harbor freight sell them... Ideally you need your 12 volts to hold steady at max charge capacity ~13.8, but if the battery is really old it won't be able to do that. Also to diagnose a clogged hybrid cooling fan without physically looking at it would be listening for it. If you can hear a fan running in the back right rear seat area and it's always running that might be the problem. My buddy rebuilt his Prius hybrid battery last January, but never checked if his fan was dirty and now he has to rebuild his battery again because it over-heated due to a clogged fan.
     
    #6 PriusCamper, Aug 7, 2018
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  7. Karah

    Karah Junior Member

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    Will a trickle charger prolong the life of the dead 12v battery?
     
    #7 Karah, Aug 7, 2018
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  8. fotomoto

    fotomoto Senior Member

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    You have a bad hybrid battery; specifically block 10. Grid charging can sometimes bring back a weak pack but not if a module has failed. BTDT
     
    #8 fotomoto, Aug 7, 2018
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  9. Raytheeagle

    Raytheeagle Senior Member

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    Block 10 is bad and you’ll need another module to swap in and replace it;).

    Within the module are 6 cells and one of them in one of the 2 modules is bad:(.

    Swap it out and then recondition the pack :).

    Good luck and keep us posted (y).
     
    #9 Raytheeagle, Aug 7, 2018
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  10. edthefox5

    edthefox5 Senior Member

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    whenever I charge or discharge my hybrid battery with my Prolong I always charge my 12 volt at the same time with a 12 volt battery charger.

    If your 12 volt battery goes dead that little battery is highly suspect to fail again.
     
    #10 edthefox5, Aug 8, 2018
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