NiCad (nickel cadmium) batteries are best known for their battery type with memory effect. In order for these batteries to work effectively, the battery must be fully discharged before charging. If you charge these batteries while they still have battery power, the battery resets itself so that you can only retain the amount of power stored during the last charge. Many electric toothbrushes, power tools and other consumer products still use NiCad battery chemistry. If your device is equipped with a nickel-cadmium battery, you can save some trouble and money with a fully charged spare battery when charging a depleted battery. NiCad battery has the lowest production cost, but due to memory effect problems,NiMH batteries are less prone to this problem and require less maintenance and adjustment. In addition, NiMH batteries can store twice as much energy as NiCad batteries without adding extra weight. NiMH batteries are also more environmentally friendly than NiCad batteries because they do not contain heavy metals (there are serious landfill problems). Note: Not all devices accept NiCad and NiMH batteries.
