Hello! I have a 2008 Prius Touring 168k miles with a hybrid battery issue. Since about a month ago I constantly get the P0A80 code when driving. I have already: Cleaned the hybrid battery fan Replaced 2 failing cells (#4 & #6) Replaced the 12v accessory battery Since I purchase the car at 142k miles around a year ago, I have had ~38 mpg and no battery issues until now. I have downloaded the Drprius app and have recorded a log of driving for a couple minutes to help diagnose the issue. You can see the battery is overtemp on startup. Why is it doing this?
Congrats on learning how to replace bad modules, not an easy thing to learn... Basically you have a bad module in your pack that is doing ok with sending and receiving amps, but it has a cell that is running hot and will soon fail. Best way to locate this hot cell is to point a thermal camera at the pack and the hot one will be much brighter than the rest. If you know anyone who does home inspections they own thermal cameras. Or you can buy a used one on ebay for less than $100 like this one: https://www.ebay.com/itm/404302872073 Key tip in buying a decent one is the size of the sensor. Some have thermal sensors so small they're worthless. The link I shared is largest sensor for lowest price. It's still fairly poor quality but way better than others at that price.
