I can get something like 1 hour and 30 minutes with plain recharge AA's... test it several times, used a Shure VP88 Ms stereo with 48v engaged and a Church audio binaurals on the the 1/8 in... or I get a lower live, about an 1 hour and 10 minutes with a pair of AKG blue line MS setup, in this case i have plugin power on, 48V on, and the MS matrix on...