Recently, I've noticed that occasionally my Prius stops turning off the combustion engine and instead constantly charges the battery at a low current of around 5-8A (according to the Dr. Prius app), even though the LCD shows a full charge (and the Dr. Prius app shows 95% battery charge). I once had to drive about 35 km (18.5 mi), and after such a trip, the battery heated up to 52°C (125°F), even though the ambient temperature was around 15°C (59°F). Turning it off and on again disables this strange mode. I always thought the Prius didn't have a cell balancing function. Unless, of course, it's something else. Anticipating your question about battery health: Yes, my battery isn't in the best condition (delta V around 32%).
Yes, that's totally a thing the gen 1 will sometimes do. My car did that HV battery rebalance thing again | PriusChat I may have freaked out the first time and interrupted it by turning the car off, but I later decided letting it complete what it's programmed to do was probably the better policy.
Interesting. I didn't think Priuses actually had something like that. I read that yours only happened once a year. Mine happens about once a month, but due to short driving distances, I haven't had a chance to finish it. Anyway, I started reconditioning the battery yesterday, so I think it won't start for a while.
Well, as it doesn't exactly flash lights and ring bells when it happens, it's probably more accurate to say I happened to notice it on the order of once a year. Also, your gen 1 is by now nearly twice as old as mine was then. You can see in the post I linked it happened once on my way home from work, and as it was a nice day with no one expecting me at a particular time, I just altered plans and made a nice detour through the countryside to watch the process complete.
I'll ask out of curiosity. Did newer Priuses and other Toyota hybrids also have this battery balancing mode, or is it just a 1st-gen thing?
