After considering 70 contenders and testing for over 30 hours, we determined that the Anker PowerPort Solar Lite is the best portable solar charger for people who want to power a phone or small device when in an emergency or off the grid. We also like the RAVPower 15-W Solar Charger, which is marginally more powerful, but a lot less portable.
Source: Gizmodo – Best Battery Packs For Stealing Free Energy From the Sun