Last Friday, I had a power outage that lasted just under 24 hours. My Droid 4 dropped to 30% battery. I want to buy a solar charger, but am unsure of what to buy. I looked at some on Amazon, but they all seem to get mixed reviews, with some people saying that they function properly and others that they take days to charge a phone using solar power. Does anyone here have a solar charger that works with the D4 that they would recommend? Thank you.