Nickel-metal hydride batteries were the next type to be used in cordless power tools. Manufacturers claim that nickel-metal hydride batteries are a step-up from nickel-cadmium batteries because they had a larger capacity and longer service life.
They too have their advantages and disadvantages.
Advantages
NiMH are lighter than NiCd batteries of the same voltage.
Compared to the other three types of batteries, NiMH are the most environmentally friendly, containing only mild toxins.
Disadvantages
Compared to NiCd and Li-Ion, they perform the worst in colder temperatures.
Keep this in mind if you want to use the tool outdoors or in cold weather.
They are more expensive than nickel cadmium batteries.
Compared to NiCd and Li-lon, they have the shortest run time.