So this afternoon, I came out to a dead 12V battery on my 2019 Prius Prime Advanced. It wasn’t completely drained, but it was giving your typical dead battery alerts and wouldn’t start the car. However, once I jumped it, the traction battery now had 15.8 miles of charge on it even though it had 0 miles of EV range on it last night. When driving, it ran on electric for the full drive as well. So could my 12V somehow have charged my hybrid battery or did the computer reset from a dead battery possibly have recalibrated the traction battery fullness to show its true charge? Super weird, but I can’t find any other instances of this happening online.
The high-voltage battery can recharge the 12V battery via an inverter and converter. But the opposite is not possible. This was only in the first Japanese-made Prius.
Let's assume that happens to someone else and they wonder what happened too? I'm not positive it happened to me (once) it may have, or I may have read it happened to someone here many years ago because there used to be a LOT of similar type questions here about weird sounds and behaviors from the plugins. If you plugged in after you got home last night. the Prime might have been charging and encountered a problem. If you didn't plugin last night, that would be another one for the weird sounds and behaviors category, but yes it's possible after the 12 volt came back online to the computers satisfaction, the EV estimate re-calibrated. What is your typcial EV estimate at this time of year when fully charged?
Perhaps the 12v being very low caused the car to lose its stored mileage estimates, and your winter range estimate turned into a summer range estimate. It sounds strange for a car manufactured in 2019 to not to use flash memory (which is cheap, plentiful, and doesn't lose its contents when it loses power), but it does seem like the car doesn't.
