I know both batteries would be best, but I don't want to spend money on two right now.
you can if the show is 2hrs or less or you build an external power supply.
Yeah, what he said. As long as you are just taping 1 band with a 1.5 - 2hr set you'll be fine. Anymore than that is pushing. You may get it, but it'll be darn tootin close!