Greetings, all. First time posting, though I've been searching the forum for input on my particular problem. No luck finding someone who's posted this one before, so Here I am. My 2010 Prius, with 381,000 miles (no, that's not a typo) got the dreaded P0A80 error code this week. Rather than spend the $3500 that the dealership quoted me, I went online and watched videos, and read here about testing individual cells within the HV Battery, to identify bad cells. After exposing all the cells, with the Bus bars removed, I find that in the un-loaded state, they all have Voltages from 7.71 to 7.74V. There are zero cells that are outside of those parameters, and I went through them multiple times. What's my next step, in terms of testing? I'm assuming that if I put a load against each cell, I might see a more dramatic difference among the cells. Am I on the right path? I'm open to any input.
If the battery is out of the car, let it sit for a week (7 days) and the bad modules will self discharge and you'll see the bad ones. Alternatively, you can try load testing all the modules too and clean the bus bars while you're at it This battery pack is not going to last you a long time, even after you replace your bad modules. The pack is worn and should be replaced. You can probably find a junk yard pack for $1000 or find someone parting out a good pack from a wreck
Welcome to PriusChat!! Clean up the HV battery fan, find and replace the bad cell(s), pick up a http://hybridautomotive.com grid charger and give it a proper balance/reconditioning.
You might also want to check both ends of all 15 voltage sensing wires. If there is a broken or poor connection, then the battery ECU will think that one or two of the 14 measured battery blocks has out of spec voltage.
