TL;DR My 2005 Gen 2 Prius with ~145k miles on it in threw a P0A80 error code, wondering what my least worst option is. What happened: On my *return trip* from a nearby grocery store on a hot day, it threw the P0A80 error code (RTOD, vsc, exclamation point). I drove it home. I cleaned the battery fan (it was a little dirty) and cleared the code. Spoiler: this did not fix the problem. I ran a check with Dr. Prius, which said the battery was in bad shape but driveable. Drive maybe 30 miles on the highway with no issues The car threw the same error code again (same grocery store, about a minute further down the road, nice comfortable day, highest temp in the battery was mid-80s). I spent a lot of time looking at block voltages in Torque Pro while using the vehicle. It looks like everything charges up great, but Block 3 tends to discharge to a volt and change lower than other cells. Block 4 as well, although not as bad. Specifically: Down to upper 14V when the next lowest is ~15.8V or 15.9V. Everything seems to charge up to ~16.9V or lower 17V. The auxiliary battery has read a lowest voltage of ~13.8V, so I don't think it's that, although it was last replaced in 2015. When driving after the code, before clearing, the car's battery monitor went from blue to purple rather rapidly, took awhile, and eventually charged back up. The internet suggests I have a bad module or four. Is it possible that I actually just have a corrosion problem? My goal is to get at least two more years out of this car (I will be out of grad school by then and have worked long enough that I can get a new vehicle). For funsies I drive to New Hampshire or Vermont or New York for climbing/hiking/whatever. It looks like getting a proper replacement done (either from NewPriusBatteries or from the dealer) is perilously close to the value of this car (did I mention I'm a grad student?). So I'm considering: Maybe I'm wrong and lucky and there's an easy fix? That's not my life story, so... Reconditioning the battery, one module at a time (well, ideally four depending on the charger/discharger I'd beg, borrow, or steal), and replacing the bad ones. I know this will take ages. Buying a reconditioned battery from somewhere like PriusKings (there's one a few miles away in Somerville). The cheapest option from them seems to be ~$600 and I trade in my battery. Getting a real professional to tell me what's wrong. I'm comfortable with handy things, although I've never worked with electrical systems. Am I missing anything? How long should I expect a reconditioning to last? How long should I expect something reconditioned from elsewhere to last? How...driveable is the car with the battery misbehaving? Can I get back to Boston from the middle of nowhere in NH?