Permanent Sticky File (suggestion)

Thier are numerous posts with various symptoms, all being caused by problems with the 12VDC accessory battery. It is important to consider what the state of charge may be and to be aware of it. If you leave a door or hatchback ajar, run the radio for hours, the battery will drain and the Prius will complain. If you do run the radio for an extended time (or any other accessory) leave the car in a full power on position so that the High Voltage battery can charge the 12V battery. The engine will run from time to time, but that's all right as the ICE is keeping the HV battery in a full state of charge, so the 12V stays charged. This only happens with full power on! In the Acc position, over an extended period of time, the 12V will drain totally and may not come back. Then you need a new battery!