This is on a 2007 Camry Hybrid with 135k. Initially we had code P3022, cell block 12 becomes weak. Found one module in cell block 12 that was over 1 volt different than the rest and swapped it out with a good one. The car ran fine for one day or about 30 miles. The next day I made it about 5 miles and it threw another code, this time P3025 (cell block 15 becomes weak). When I hooked it up to Toyota Techstream it showed cell block 15 reading 16.56 volts. The other cell blocks read between 16.29 and 16.49. A little odd that it was reading higher.

So today we took it apart and tested voltage of each module. They are all 7.86 or 7.87, including the two modules in cell block 15. The buss bars have corrosion on both sides but probably no more than a typical 07 with 135k miles.

Now that all wiring/buss bars are removed I will let it rest a few days to see if there is any degradation of voltage in any modules. If not then I'm thinking my next move on this is to replace the buss bar on both sides and both modules from cell block 15 and see what happens but I wanted to get some input and see if there is something else I should be looking for.

Thanks

 

There is a local guy here that rebuilds these batteries. I believe the local dealer here outsources installation and battery testing to him when there is a problem. Anyway, we talked briefly over the phone last year. He says the the bulk of the issues with these batteries is from corrosion across the bus bars causing wacky readings. I thought that was interesting and I always had it in the back of my mind that if ours ever failed, to just replace the affected cells and bus bars.

Let us know what happens with all of that! I am very curious!

 

Thanks for the response! I hope your local guy is right because I can't find anything else wrong. I have had the HV battery out of the car with the bus bars taken off of both sides for the last week to see if there is equal drop in voltage. They are all very steady at between 7.74 to 7.76. However, the bus bar does have corrosion so I soaked them in white vinegar and gently brushed them with a toothbrush. I should probably just put in a new wiring harness/bus bars but they seem to be very clean now. This weekend I will put it back together and give it a try. I'll let you know what happens.

 

Where are you? I can put you in touch with this place here. Not sure about protocol posting that kind of stuff in forums. He "is known" for his work. Especially in the Prius community. I can PM you his info. It might be worth a phone conversation with him, since he has taken the time to disassemble and rebuild these battery packs. I believe he even designed his own charger for the purpose of rebuilding batteries.

EDIT: PM sent. I would definitely contact this person if I was having any battery issue.

 

AJ, Are you talking about Bob?

 

David, I was refering to Josh over at Mellors in West Melbourne. I PM'ed him Their info. Funny about this.... I may go to them to have some of my work done as well.... I just forgot about them until this battery issue came up.

 

Thanks AJ,

I know that Bob has helped several people out and also built his own charger and has rebuilt packs before. Then again, he IS a rocket scientist.....

David