[EricH]

Originally Posted by Mark McLeod

The backup battery isn't actually needed to operate normally, especially for demonstrations. It's effect is only noticeable if you have a low battery or a very draining pushing contest, then the robot just stops for about 5 seconds before continuing on.

Maybe, maybe not... If the main battery gets too low, the IFI controllers didn't have the capability that the cRIO does to cut power to the motors before the controller. So, you could get the case where the motors take all the power and the RC gets none, AKA an uncontrolled robot that the E-stop can't stop. It's happened (IRI 2002 for one instance).

If you operate without the backup, set the OI LED screen to show the battery voltage; if you start getting down in voltage, change batteries.