Prius (2004-09) :: 2006 With 160k - Red Triangle / Repeated P0A80

A couple months ago, my car suddenly got the red triangle. The dealership said that I needed a new battery, and eventually a new water pump. I couldn't afford $4500 as I bought the car just 9 months earlier and am making payments on the car.

I found a guy that was to "recondition" the battery, which set me back about $1200+. After getting it back, the car has been making a rattle sound in the engine bay when under acceleration (it sounds like a loose screw, but I don't know).

After about a month, I got the red triangle again. The car's performance deteriorates, the state of charge fluctuates a lot more. One minute it is green then literally a minute later it is purple then green again. The guy that reconditioned my hv battery said all the cells are good but for some reason became unbalanced, so he put it on the grid charger and rebalanced it (I believe it was on there for about 24 hours).

2-3 weeks later, it happens again. Same thing, the guy says it is unbalanced again and stuck it on the grid charger (because of time constraints, it was only on the grid for about 5 hours).

Then again 2 weeks later it repeats itself. A couple days before it happened, I tried out the elm327 adapter, custom pids, and torque app. Before the triangle came on, the delta state of charge got to about 0.9% and was charging up to just about 90% and down to just below 39%. Same thing though, from high to low in a matter of less than a minute. Same code P0A80. Sitting on the driveway, all 14 modules would be consistently within .2 volts. But when the car started acting up, I saw a voltage difference of about 3 volts between highest and lowest modules. The repair guy said the same thing again. The cells are good but got unbalanced again. This time he recommended for me to leave the car for the weekend so it can sit on the grid charger for a minimum of 24 hours, which I did. I picked it up yesterday and it's driving fine right now.

He is also recommending that I buy a grid charger and charge the battery every couple weeks to avoid these problems. I mean, how do I know if he actually reconditioned the battery, or has just been resetting the fault code and grid charging the battery? Btw, I did the auxiliary battery test and it was perfect. I don't know when the battery was last replaced but I believe with how strong it is, that is was done sometime recently before purchasing the car late last year.