[EricH]

Originally Posted by KenWittlief

I think the battery supplys the power to the servos - the little hobbie servos. If you are not using any on your bot, you should be able to run without the backup battery.

Yep, that's right. We had ours on the bot but not charged, and we could not use our one servo. Everything else worked perfectly. Soon as we charged it, the servo worked. The only other thing the backup does is to keep the controller powered if the main battery somehow fails. So as long as 1) you have no servos and 2) you keep your main battery charged, you should be fine wihtout the backup.