Gadget guys like me burn through a lot of batteries. That’s why I loved the USBCells, which work like standard AAs, but recharge off of any USB port. I used the same two sets of batteries all summer long in my headlamp and GPS. In between trips, when I didn’t have access to an outlet, I was able to pull power from my laptop (left in my car at the trailhead) or use a USB-compatible solar charger (see left) to juice up.
It typically takes seven hours to get a full charge, and while the batteries only last about half as long as alkalines or other rechargables, the convenience of charging off of the grid more than made up for that. $18 for two; usbcell.com.