The deneke ps-2 phantom box pulls 280, so just to be safe say the ua-5 w/o phantom on is only pulling 250, with .8 (can't drain 100%) factored in. that gives you 5 hours on a 1600mha
I've never run longer than 4.5 without switching, but it's a safe bet.
Can any of the electronically inclined tell us how to measure the actual amp draw of the ua-5 w/o phantom on?
JAson