(NiMH) A rechargeable battery technology that has approximately 30-50% more charge per pound than nickel cadmium. Introduced in the early 1990s, it uses nickel and metal hydride plates with potassium hydroxide as the electrolyte. NiMH batteries do not suffer quite as much from the "memory effect" as do nickel cadmium batteries, but still require complete discharges in order to obtain the most efficiency and longest life. See batteries and nickel cadmium.