The most common power source for  LED Flashlight  is the battery. Many types of batteries are suitable for use in flashlights, such as button cells, alkaline batteries, lithium batteries and rechargeable NiMH and lithium ion batteries. The choice of batteries will depend on the light source used, and will usually play a determining role in the form factor of the led flashlights wholesale.

Some mini led flashlight are solar powered, using the energy generated from a solar cell to charge an on-board battery for later use.

Some LED Flashlight have an electrical generator built into them. One type of dynamo-powered flashlight has a winding crank connected to a small alternator that feeds several diode bridges with their outputs connected in parallel feeding a field effect transistor that charges a capacitor that connects to one or more LEDs. Others generate electricity using electromagnetic induction. They use a strong permanent magnet that can freely slide up and down a tube, passing through a coil of wire as it does. Shaking the flashlight will charge a capacitor or a rechargeable battery that supplies a current to a light source, typically a light-emitting diode or, more rarely, an incandescent light bulb. Such flashlights can be useful during an emergency, when batteries may not be available

Another less common type of flashlight uses a High Intensity Discharge (HID) lamp as the light source. HID lamps work by discharging an electric current between 2 electrodes in a capsule filled with a mixture of metal halide salts and argon, producing an extremely bright light.

Some advantages of this design are that they produce more light than an incandescent flashlight using the same amount of electricity, and the lamp will last longer and is more shock resistant than a regular incandescent bulb. However, they are much more expensive (due to the need for a ballast and other circuitry to start and operate the lamp) and are usually rather bulky. An example of an HID flashlight is the Surefire Hellfire Weaponlight.