I try to be power self sufficent while traveling, and I've used several different iterations of solar charging solutions... I've used a Solio for the last couple of years, issue with it is that the recharge time is fairly long, and if you need it on a daily basis, it will not have a full charge, although it has a lot of adapters, and has been trouble free/compact. Mine usually takes two days of hanging on the pack/in the windshield to get a full charge... I've had better luck with the solar backpacks from Voltaic Systems. They have a bigger storage battery, and the panels charge it fairly quickly. Since you don't need another pack, during an Alpine ascent, I'd recommend a Flexible panel from Global Solar (also personal experience) or something similar.