Check a little further down this board & theres a thread on field-powering the UA-5.
I kind phellow made & mailed me the y power connector for R/C packs & it works great, took it and my new UA-5 out for its maiden flight last Wednesday.
I picked up a 3000mAh 9.6v pack from
batteryspace.com and it lasted the whole nite (about 6 hours). I've heard people say they've got 7+ from it while supplying phantom.
The pack was $30+shipping and came with a charger.