Our original crank lights are not the cheap lights you see in the discount stores. You can drop ours on the deck of the boat or have it tossed in a Hurricane and they keep working. You can crank them underwater and they keep working. The whole point is technology has progressed to the point that a good underwater crank light is now affordable and will last for five years. Why even risk finding your safety kit light has a dead battery. Forget the battery routine all together.