[Al Skierkiewicz]

Michael,
<R53> The 7.2v backup battery may be charged on or off the robot. When off the robot, the battery is to be charged with the provided 7.2V backup battery charger. When mounted on the robot, the backup battery may be charged from the EX18-12 primary battery by using the custom charging circuit available from Innovation First Inc. (note: IFI will provide the design for this circuit on the IFI website, however teams must obtain the parts for this circuit and assemble it themselves)

The rule book is your friend. I suggest everyone download the manual to your laptop or shop computer. Acrobat reader has a nice search feature that helps me in finding answers quickly.