Codes P0A94, P0AA4, P0AA1 for 2005 prius. Cant figure out whats wrong.

Hey guys, just joined this forum as i am having issues with my 05 Prius. I will start off from the beginning. I just bought the car last week to flip it. p/o stated it needed 2 cells and he had it checked by the stealership. well sure enough.

took apart the battery and all of the cells tested at 7.85-7.86 except for two cells which tested at 6.5. Replaced both with ones that were at 7.55. i didn’t bother to balance the battery since i figured they will charge and balance over time. drove the car and the battery on trip info held charge great. couple min in the Red triangle along with the other lights came back on. no worries its probably panicking since two cells are lower. drove the car around a few miles and then parked it.

today, i took of the battery case and took off the bus bars to remove the corrosion off of them. tested all cells again and all were still around 7.85 but the two had now charged up to 7.80. cool. its working. put the case back on and went for a drive. it was driving perfect. did multiple 0-60 pulls with no issues while monitoring temps and codes and performing full battery tests through Dr. Prius. decided to take the car on the highway to just charge it up more.

On the way back home, the ABS, TCS, and VSC lights came on. and then the car just died and went into neutral. the infotainment system went black so the 12v battery seemed sus. eventually only thing that would happen when i went to start is the CEL would come on. Anyways. jumped the car from terminals upfront and it was ready with no issues. no lights and drove perfect all the way home until i reached the driveway where it threw the red triangle and CEL and died. Restarted it immediately and just parked it on the driveway. Checked codes and they are P0A94, P0AA4, and P0AA1.

I know nothing about hybrids and this is my first prius. one thing i noted is that after the jump the 12v was steady at 13.40v, just checked right now with the car off. its not starting again and 12v battery is at 8.6V. seems like something is draining power or maybe a bad 12v battery? not sure why those codes would come up then. maybe just freaked the electrical system out because of low voltage like my german cars tend to do lol. any help/ tips would be greatly appreciated. it has 117k miles on it and was parked for a year i believe when the owners were in Africa. so maybe the 12v battery is the issue but it should not be draining that much with the car off.