So this last week my wife’s Prius had the check engine light (as well as a few other lights on the dash) pop up as she backed out of the driveway. Car is a 2012 with 200k and for what it’s worth it was 98 degrees out when it happened. I got home yesterday and scanned the car and am seeing P0A80. In other post I have seen people who get this code usually also get a message check hybrid system or something of the such pop up but hers never did that. I tested the 12v and it tested 12.42v. I cranked the car and it ran for awhile all like normal and the meter on the dash showed that the hybrid battery was indeed charging up while the engine ran. I took a few screenshots in Dr Prius hoping it would be of some benefit. The numbers seemed to fluctuate so I posted a couple. I plan to plug up techstream tomorrow to see if it can give me some more info. The car still gets good gas mileage and I have a prolong hybrid charger but have never used it on this car. Can anyone tell from these screenshots if there are any problematic cells that needs to be replaced first before using the prolong?
I think that the hybrid battery modules are okay based on the Dr Prius screenshots that you uploaded. The main problem is that the Delta SOC (state of charge) is 34.0%. What that means is that the battery modules are not balanced to each other. When that happens, the voltage difference between the battery blocks (two battery modules= one battery block) becomes large enough to trigger the P0A80 code during high current flow through the battery. A healthy balanced battery has a 0.00% Delta SOC. To balance the battery modules to each other, you need to use the Prolong grid charger to top balance the battery pack. Follow the instructions on Hybrid Automotive's website. Going from memory, you want to charge for 20 to 24 hours. Take note about the maximum ambient temperature in the instructions. Also, make sure you let the battery burn off the extra voltage in the battery by letting it rest fot 4 to 5 hours before starting the car. After doing this, monitor the Delta SOC of the battery for the next few weeks and then every month or so. When the Delta SOC starts increasing again, use the Prolong charger again. Hopefully, you can go 6 or more months between charges.
Your screenshots show voltage values while the battery is being charged or a very small discharge. This hides a lot of problems. Your best condition evaluation will be performed when the battery is being discharged a bit heavier. You can do that by completely warming up the car, then running the AC on full blast while monitoring voltages. This way the car engine will stay off until the HV battery reaches 40% ish or a weak module shows itself and it needs to start for battery charging. Rarely ever can a good evaluation be performed of the modules when the HV battery is under charge conditions. Another question is about how long does the car sit unused? At that age and mileage, assuming the original battery, sometimes even sitting over a weekend unused will allow a weak module to self-discharge enough to drop the indicator to 2 or 1 purple bars. The good thing is they will usually charge back up, and as long as the car is used frequently, you'll never notice a problem.
All those Dr. Prius screenshots were taken with the battery charging or with a very slight discharge @ high SOC, outside of the delta SOC reading the rest of it isn't very useful. After it sat overnight and before starting the car, turn the ignition to ON, ready mode off by not holding the brake while powering on the car take a screenshot of the battery voltages. This will give us some idea of the self discharge of your battery. Start the car, let it warm up until the engine shuts down. Turn on the A/C on the coldest setting and fan on high, turn on the headlights including high beams, engage the parking brake and put the car in reverse, make sure it holds. This will put a 10-15 amp load on the hybrid battery, keep it there and continue to take screenshots. Post only the last screenshot you took before the engine restarted and began charging the battery. This will give us some idea of how the battery performs under a light load @ low SOC.
