ReVIVE Solar ReStore XL 4000mAh Solar Charger Power Bank & USB Rechargeable External Battery Travel Pack w/ Universal USB Charging Port & High-Efficiency Solar Panel for MP3 Media Players, Smartphones , E-readers , iPad and More!
This works great as a battery backup, but not as a solar charger. I've had it out in the sun on backpacking trips, in the car, and even in the window of my apartment. I'm not sure it's charged at all. If it has, it's so slow that it's not helpful away from a power source as a solar charger. I have charged it completely a few times before going on weekend trips. Then it gives me enough juice to recharge my iphone a couple times. It's worth it for that for what I paid for it, but bulky and heavy as a battery 