How do shake to charge flashlights work? Do they need batteries?
These flashlights generate their own electricity and never need batteries. They gave an internal generator, usually a magnet that slides back and forth inside of a coil of wire. The energy is stored in a large capacitor that then powers the LED or incandescent lamp. They are good emergency flashlights, but are not as bright as regular flashlights, and generally require frequent recharging.
