Did a test last night with the PS-2 hooked up to a pair of km184s and using a standard Duracell 9V, and got about 5 hours (2 hours at a show, and 3 hours at home) of battery life until the red low-power light came on, and then a little more than another 1 hour until the thing died. Seemed like it was performing fine until just before it died, though, when I tested it periodically. I plan on trying some Energizer Max 9V next week.