The series 1 Prius hybrid has an inbuilt inverter that can be used to charge the main nimh battery with a 12 volt battery. This feature was dropped in lter models.
How to charge the nimh battery with the inverter.
1) Connect a 75 ah or larger battery in place of the 12 volt battery. The standard 12 volt battery does noy have enough capacity.
2) Start the vehicle. The nimh 288 volt fault indicator will display.
3) Remove the ignition key
4) Press start on the inverter in the car boot.
5) Charging will start
6) Allow charging to complete
7) Start the vehicle.
8) Let it run to charge the battery completely
9) Reconnect the 12 volt battery