BigBlue [Upgraded Tiny Solar Charger] 14W SunPower Solar Panels with USB-A Port(5V/2.4A Max), IPX4 Waterproof, Portable Solar Phone Charger Compatible with iPhone X/8/7, Tablet, Samsung LG etc

High energy conversion: BigBlue 14 W portable solar charger use rear contact solar cells (BC) that achieve an efficiency of 25.4%. To obtain a good yield on a very sunny day, the solar panels must be placed so that the solar rays are reflected perpendicularly on them