Here is a solar power bank for your smartphone that can also generate energy when you crank its handle. The MAXOAK Hand Crank Solar Charger has a 7800mAh battery inside. It has over-current, over-voltage, and other safety features built-in.
Keeping the power bank charged during the day is easy but at night, you can simply crank the handle clockwise to generate electricity. The device is compatible with iOS, Android smartphones, GoPro camera, and GPS devices.