VEX IQ robot battery questions

Our 4-H club will be demonstrating VEX IQ robots at an upcoming county fair. We may not have power available in our booth. We are new to VEX IQ and haven’t competed with these robots yet. We have competed in VEX for several years.

Here are my questions.

How long will a fully charged VEX IQ robot battery last if the robots are in constant use?

How do I purchase the holder for AA batteries? According to the manual, the robots can be powered with AA batteries, but the holder didn’t come with the kit, and I don’t see the item listed for sale on the VEX IQ website.