The USB Solar Charger (1,800mAh) is the device of the transferring the solar power into electrical power, it is working as: the solar panel transfer the sun energy into electrical energy which is stored in the built in 1,800mAh Lithium battery, the stored power is then exported to mobile phone, Tablet and MP3/MP4 player, of which the process is done by the control circuit, and the different adaptable connector. The AC charge is designed for continual overcast days when there is no sunlight; with the AC charge function customer can charge Lithium battery with USB power outlet. The USB Solar Charger is the ideal backup power supply for business trip, traveling, long distance journey, wildness working.