I can't seem to find any good info on battery pack based chargers for USB devices, mainly my Edge 305. My trips can take me into the boonies for a few days so now that I have one of this things I need to be able to charge it.

Don't think I wanna go dynamo, I'm over-experienced with Solar (off grid for 8 yrs previous) and it seems the battery pack would be the simplest, least expensive route to go. Really would like Solar/battery combo but they look expensive and I don't think I believe much of the recharge hype from their solar specs. Plus keeping a panel in full sun all day on tour would be tough or I would consider building up a unit myself.

Any experiences with battery pack chargers?

Bruce