Solar charged camera

The Olympus xz1 and xz2 as well as the Sony nex 3n and some other nex models charge directly via USB but you will need to carry the cable to charge. The cable can weigh as much 2 oz themselves.

You can get a .3 ounce ppuclip to charge any 3.7v batteries or the c-usb charger for 7.4v batteries and I would recommend that instead.

I meant to say that I recommend the ppuclip or cusb charger depending on the camera you choose. Smaller cameras only need the ppuclip.

The Sony RX100 is charged via a micro USB port which is probably the same connection as your headlamp. Not cheap, but the image quality and size make it worth while

The Olympus Tough cameras charge via USB. I have the Olympus TG 820 and really like the picture quality but it's a brick! Since I have a history of being hard on cameras, I accept the extra weight as a necessary trade-off for my camera surviving being submerged and dropped frequently.

I used the Powermonkey with a Sony RX100M2 on a 13-day hike last fall. It worked really well. But I did find that some USB cables work for that combination and some don't. Not sure why.