What is NiMH battery?

The voltage and performance of the NiMH battery is similar to standard alkaline batteries in those sizes; they can be replaced for most purposes. The ability to recharge hundreds of times can save a lot of money and resources. They are often used in digital cameras and perform well and applications that require frequent replacement of the battery, such as toys or video game controllers, also benefit from use of rechargeable batteries. With the development of low self discharge NiMH, many of occasional use applications can be replaced with NiMH rechargeable battery.

NiMH batteries are particularly advantageous for high current drain applications. Alkaline batteries, which might have approximately 3000mAh capacity under low current demand (200mA), will have less than 1000mAh capacity under 1000mA (reference). Digital cameras with LCDs and flashlights can drain over 1A, quickly depleting Alkaline batteries after few shots. NiMH can handle these current levels and maintain their full capacity.