On this previous trip across Iceland, we needed to figure a way to recharge our camera batteries since we would be at least 3 weeks without electricity. I brought a solar charger on amazon from powerfilm (F15-600). Although it was useless on the countless rainy, overcast days, it could recharge a Canon 5d Mrk ii battery in roughly 3 hours when the sun was shinning. The solar blanket is super light and compact and could be strapped to the back of my pack while hiking. I also had tested the smaller version earlier but it was not successful. If you have the space and the money I would suggest going one level up to allow for charging on slightly overcast days as well. For the charger to work properly with the solar panel you will need a charger that can connect to a cigaret lighter, there are many on ebay for sale for under 20 USD with extra battery.