When I briefly looked at solar chargers it appears that as with most things you get what you pay for, the efficient panels that will charge on a grey cloudy day are still expensive. The cheaper ones take ages to charge except in full sun. Some of the Powermonkey ones charge a battery unit which then can be used to charge the device. The battery unit can be charged from the mains or usb if in a hostel etc.
When I briefly looked at solar chargers it appears that as with most things you get what you pay for, the efficient panels that will charge on a grey cloudy day are still expensive. The cheaper ones take ages to charge except in full sun. Some of the Powermonkey ones charge a battery unit which then can be used to charge the device. The battery unit can be charged from the mains or usb if in a hostel etc.