A new portable option which can charge your devices on the go is the Blue Freedom, a tiny 7.9 x 2.2-in hydropower kit that is lightweight and can fit in a small backpack. The kit contains a 4.7 inch diameter micro turbine, a 5W generator and 5,000 mAh lithium-polymer internal battery.
By dipping the turbine into running water, while the base unit stays on the shore, you can charge your devices. You can charge devices directly from the base unit via USB ports or let the internal battery store the energy for later use. The company estimates that an iPhone would get 10 hours worth of charge with the turbine spending just one hour in the water. A smartphone would fully charge in 2 to 3 hours while the internal battery can fully charge in just 3 to 4 hours at a water flow rate of 1.2 m/sec (2.7 mph).
© Blue Freedom
The promising mini-sized hydropower plant is currently raising money on kickstarter.