I am soon to be a proud owner (tomorrow ) of a Bongo HH. I was wondering what the battery life on this will be. Say, a gig consists of 15 songs max, with little or no break between them. Before someone posts it: Duh, I can have backup batteries. Duh, it depends on playing style, etc. I'm just curious so that I have an idea of when to check. Give me as general of an idea as you can. Thanks!