for being portable id still recommend the Go+play. It's output is 120w and weighs under 10lbs. I think it would tear that 22w mono PA system IMO. watts don't mean everything but this is very good. you just dont get a mic and guitar input but something worth looking at.

as for the batteries, I get mine for free but i looked into them and you can get the rechargeable D's for about the same price as a replacement battery for the Bose portable sounddock.