If it doesn't suck up battery power, do you use a light to view? Batteries for a light would be another issue. I keep a petzel light with me at night in my hammock but use my MP3 player for listening to music and books etc. I only use it for a couple of hours each night and the batteries last for 5 days using the device like that. I fully charge before I leave home and usually have some battery power left when I unpack back home. It's a 6gig sansa referb from woot for 45 bucks. That's the only electronic device that I carry now. I carry 2 extra batteries for my Petzel and that's it.