I carry a battery pack when backpacking for charging my phone(GPS/camera/ballistic solver/e-book) and headlamp
LOL< we do too, but the wife carries it for charging her camera batteries. I wouldn't touch it, she takes all the portable memories with the cameras....
Come to think of it though, I suspect I could easily carry 2 gel cell 12 volt deer feeder batteries in the 6 wheeler out to camp in the bush and charge lots of stuff off htem before they died... great idea... to damn late to get the Revolt though... ugh...