The NightStar flashlight is the most reliable hand-held light source ever made. Those unfamiliar with its design have asked several excellent questions. The capacitor in NightStar can only power a filament light bulb for a few seconds. By comparison, the energy stored in a battery is great enough to power inefficient devices for several hours. However, when a battery's energy is depleted, it either has to be discarded or recharged.
Rechargeable batteries require external and often costly charging devices.
Additionally, energy capacity diminishes with each charge and after 25 to 50 recharges the battery is rendered useless. Besides being inefficient, an incandescent bulb also has a lifetime of only 500 hours and is extremely fragile. Quite frequently, a bulb will break before it burns out. Therefore, for reasons of energy efficiency and reliability, an LED is the logical choice for the NightStar flashlight. The ETS Cell within NightStar can power more than one LED and with each LED added the light output will increase.