Best way to charge ipod touch 5 while camping?

I'm going to be camping out 2-3 days for a concert on February 20th, and I'll need to have my ipod touch with me. I've seen external battery packs and solar chargers for apple products but nothing that would fit with the new usb port on the ipod touch 5 and iphone 5.

I'll be getting a new phone soon, and I'm hoping to get the iPhone 3 or iPhone 4 which would work with older models of external battery packs and solar chargers but I'm still looking for one that would work with the iTouch 5, and if not I'll have to bring my old ipod touch 4 with me and buy an older external battery pack.

Does anyone have any suggestions for external battery packs or solar chargers that are compatible with iPhone/iTouch5? If not, does anyone have any suggestions for good, reliable battery packs or solar chargers for iPhone/iTouch 4 that I can use while camping out?

Thanks in advance!