Sluggish acceleration, low MPG & POA82. Fan clean and working

Hi Everyone,

I need some guidance and opinions with my 2010 with 173K that I purchased at 145K which seems to be having some issues with the battery. I'm here in Texas and it was warm this weekend mid to high 80's. Went on a 200 mile road trip Friday night and MPG which is usually 42-45 was 36 and battery fan was running on high a lot. Saturday morning reset the mpg and it was back up to 45 but later in the day when it was hotter outside we were back down to 36 - 39 although car had been sitting in the shade. Yesterday morning when the battery was cool mileage was good again but part way into the trip home mpg dropped again and car was very sluggish which was not a surprise since the fan had been running on high the entire trip. This is my second summer with the car and don't recall any of these issues last year.

I had my OBDII dongle and got a pending P0A80 code but did not have my tablet with Dr. Prius with me. When we got home i scanned again and got P0A82 pack over temp. No lights or warnings have come up just the low MPG and sluggishness and the pending codes. Any ideas or direction where to go next would be greatly appreciated.

Here is all the other related info.

Since I've had the car you can park it with 4 or 5 bars on the battery and when you come back an hour or two later it will be at 2 bars when you turn the car on. Dr. prius test says battery has 40% life left assuming i did the test correctly. Battery health test had no errors either.

Can not force charge the battery more than about 65% currently and it takes more then just being in drive with the foot on the brake and flooring it. You have to let off the gas and floor it again to get it to go up any. it did force charge during the Dr. Prius test and now it won't do it again. When you try to force charge it will go up for a few seconds and then it's like the engine decelerates and you can hear an audible difference like it has stopped charging the battery. When it does charge there is a whine kind of like the generator engaging and then disengaging.

Busbars and nuts were replaced about a year ago and corrosion cleaned from all connectors. Battery fan cleaned around the same time. Verified today it is working correctly, has suction at the intake and good exhaust in the trunk.

12V is about 2 years old from autozone. Came with the car so don't know that history. Voltage at the terminals is 12.5 and 11.5 on the nav screen diagnostics. Drops to 11.4 on the screen with the headlights on and goes up to 13.7 when put in ready mode.

Complete EGR cleaning, engine water pump and thermostat, inverter coolant and transmission fluid done at 145K / January 2022. Car does not burn any oil between changes and does not lose any coolant. have also verified the inverter pump is working and it did also have the recall software update done before I got the car.

Have also notice sometimes the A/C does not seem as cold as it has been and other times it's as cold as you would expect it to be.

 

Yeah I did think about that but Dr. Prius and hybrid assistant didn't show anything out of the ordinary. Just got done cleaning the fan again which was dusty but not bad. Also checked all the bus bars and everything looked good there.

Odd thing was when i reconnected the 12V and put the orange plug back in the car showed almost a full battery. Once it started up it quickly went down bar by bar to one bar left and Dr. Prius showed 26% charged. I let it run for a while and it went up to 63% but the display showed all but one bar full.

I'm sure there is something going on with the modules but not really feeling like replacing a module here and there. Luckily we have a local hybrid shop that does refurb and brand new Toyota batteries so going to call them tomorrow and see what they say about checking out the battery. Planning on keeping the car a few more years so may just bite the bullet and have a new battery put in it.