These solar power banks come in five colors, and all are currently on sale. The battery in this charger is a 20,000 mAh lithium-ion model, enough to charge an iPhone four to five times ...

This human powered cell phone charger is a great example. Using just a few ordinary around the house items, [The King of Random] turned a cordless electric drill into a human powered electrical ...

A few years ago, [Lukas Fässler] needed a solar ... the power generated from things like solar panels varies under different conditions and loads. An MPPT (Maximum Point Power Tracking) charger ...