Maybe I'm preachin' to the choir here, but I urge you to run dual power with the 7xx boxes. Not that the 7xx boxes are particularly power hungry or the attached battery is unreliable, but with two power sources you can just about quit worrying about running out of power. I've come up with two different DIY solutions to external battery power via the Hirose connector and now I almost never use AC power. The biggest problem with external power is soldering to the tiny Hirose connector, but there are people here who will build you a cable if you don't want to mess with it.