Depending on the size/watt of the panel you get. The guy in the next office from mine has one, and he is able to mount it to his car window. He still has the mount there, so I guess he's using it and it works for him. I'll inquire to him about it later.
I can tell u from experience. Small solar panels the size of ur hand will not be sufficient to charge ur phone. you have to get 1 that's pretty big in size in order to use it properly on your smartphone. 100 dollars on a good solar panel charger will be a good number to spend. I saw charger at fry's electronics 4 about 100 dollars that would charge your cell phone and 4 rechargeable batteries. I would get something that has a solar panel at least 3-4 times the size of your phone.
I forgot to mention that the little solar panel chargers take a looooong time to recharge the inner battery and ur cellphone. I had one I bought at radio shack for 50 bucks. And it was the worst ive bought there. it took about 1 week to charge up the inner battery. and it only has about 1,000 mah capacity.
Found this cool item that has about 8 times the average battery in a smart phone.
I've been looking at the solar charging backpack that supposedly charges your laptop and other electronic devices. If it charges my laptop, I could charge everything else from it. The reviews weren't bad, and the solar panel is fairly good sized and removable. There are so many options, I keep putting it off in favor of something edible.
I just returned a Goal Zero nomad 7 to best buy today, it's too small couldn't charge anything, left it hooked to my old phone for 6 hours on a clear and sunny day, and it literally lost power.
I was thinking about trying the Goal zero nomad 15 because it's essentially double the size, if it doesn't work i'll return it as well....bad news is I still have 60 bucks on a gift card at best buy and i have NOTHING to get there.
Acidlittle you can always go to cardwoo.com to sell your gift card. Or sell it to someone. I know if people like to shop at academy or any other major store that has gift cards. You can always buy gift cards cheaper and use them at stores.