[X-Istence]

Low Backup Battery is a problem that my team had last year as well. What we ended up doing was using a VEX 7.2 v NiCad battery instead since they are the same batteries that are found in RC cars and other such items. They are legal under the FRC 2007 rules as well.

The other options is to use the wire diagram on the IFI site to make a battery charger that charges from the 12V battery, in which case it does not matter what kind of battery pack is used for the 7.2V's.