One of the most consistent problems with flashlights is that their batteries always seem to be on the verge of dying. To solve this dilemma, innovative companies have begun to sell an impressive array of rechargeable and solar flashlights. A wide variety of mechanisms have been spawned for the powering of these flashlights, from crank and shake style generators to simple solar and rechargeable styles. All have their pros and cons, and to the layman looking to buy a simple flashlight for emergency or recreational use, stepping into the market without a firm grasp on the differences can be daunting.
Generally, rechargeable flashlights can be sorted into three categories: traditional rechargeable flashlights, which are plugged into a wall and charged in advance; solar flashlights, which are charged in advance by ambient sunlight; and other rechargeable flashlights, which encompasses shake and crank flashlights.
Traditional rechargeable flashlights are the most common, and they are charged by plugging the flashlight into the wall via a charging station. Solar flashlights can be charged by full or partial sunlight. Both of these types require at least a certain amount of charging prior to an emergency situation. The other category usually centers on flashlights that can be charged at a moment's notice, such as shake lights and crank-operated flashlights. In general, these give slightly less light than their more traditionally powered counterparts, but require no stored electricity to run.
When one of these flashlights, it's important to keep in mind the intended use of the light, as well as where it will be used. Solar flashlights are good if you have an abundance of sunlight in which to charge them. If full or partial sunlight is a rarity in your area, it's better to steer away from solar power and concentrate on traditional rechargeable flashlights instead. If the flashlight is intended for emergency use only, or for use in a vehicle, crank- and/or shake-powered lights may be the best option.