batteries

the 12 volt battery in the Prius runs the lights and fans and windows and rear defrost and all the dash instruments power door locks virtually every thing other than starting the ICE and making the car move. Just like in a regualar car. The high voltage battery only powers the the drive motor and the motor generator to start the ICE, and the air conditioner compressor. The 12 volt battery is charged via the converter on the bottom of the inverter, it takes High Voltage and converts it to DC and drops the voltage to 13.8 to 14.2 volts to charge the battery.

 

Well said. Yes, the car has a conventional 12V main electrical system, but instead of an alternator connected to the engine maintaining the 12V charge while the engine is running, it is done using a solid state power supply much like your computer power supply at home.

Also note, the HV power leads are isolated from ground. In other words there are 2 HV wires going from the HV battery in the back to the inverter under the hood. The HV battery is 206V nominally. It is charged using the same motors (MG1/MG2) that Frank mentioned except they are used as generators.