I havenâ€™t had any trouble with my 2007 Prius until last night. I was at the gas station, trying to close the window after talking to the attendant (no self-serve in OR). Just as it was dawning on me that the window was closing very slowly, the MFD beeped and gave a message about a transmission problem, â€œpark on a flat surface and fully engage the parking brake.â€ Then the MFD went black, though the radio kept playing. The car was turned off, of course, since I was getting filled up. Managed to start up and drive home (2 blocks), and when I went out to investigate later in the evening, the cabin light and MFD were very dim. I havenâ€™t measured battery voltage but imagine itâ€™s pretty low. My question is, do I need to replace the 12V battery at this time, or would a AAA jump suffice for now? Four years and 61K miles doesnâ€™t seem like a long enough lifespan for the battery. The gas station was the second stop on the way home yesterday â€“ 15 miles of highway commute then one brief stop, then another couple miles to the station. No problem starting the car until I tried to start her up last night to swap cars on the driveway to have a known-working ride to work today. I donâ€™t think I left any lights on or doors open, and even if I had â€“ wouldnâ€™t that have caused problems when I tried to leave work yesterday? No way I could have drained it during that 3-minute stop. This car is a daily driver, c30 miles round-trip commute and odd jogs on the weekends. Weatherâ€™s been around freezing and dry lately, so Iâ€™ve been driving with the defroster/heater on quite a bit, but never try to run those without having the car in Ready mode. I canâ€™t think what I might have done to drain the battery, and Iâ€™m surprised itâ€™s dead. Also, I havenâ€™t been seeing the odd symptoms reported by other PC posters, fluctuating SOC readings and the other odd things that happen when the 12V battery starts to go out. So, please advise â€“ jump or replace?