Self-powered equipment is a term used for electrical appliances which can be powered by human muscle power as an alternative to conventional sources of electricity such as primary batteries and the power grid
Such devices contain electrical generators or an induction system to recharge their batteries. Separate crank operated generators are now available to recharge battery powered portable electronic devices such as cell phones. Others, such as mechanically powered flashlights, have the generator integrated within the device itself. A promising alternative to rechargeable batteries for electricity storage is supercapacitors, now being used in some devices such as the mechanically powered flashlight shown here.