A wide range of NiMH (Nickel-Metal Hydride) battery chargers exist, from small AA/AAA units to large models that charge several types of batteries. The battery types, capacity and charging time are a few important aspects to compare when purchasing NiMH battery charger.

 

Capacity, Types

Compare the different types/sizes of batteries the chargers can charge. It's best to have the widest variety of options available, though many people don't need to charge any C or nine-volt batteries. Also consider the battery quantity different NiMH chargers can hold at one time.

 

Charging Time

Check how long the charger takes to charge a battery. Don't compare apples and oranges; it will certainly take longer to charge a D battery than a AA cell. It's also good if the charger has a charge timer function; this helps prevent overcharging, which can cause battery damage.

 

Other Features

The ability to also charge NiCd (Nickel Cadmium) batteries remains useful if you already own rechargeables of this type, though otherwise unnecessary. Some NiCd/NiMH chargers have a discharge/conditioner feature. According to RadioShack, this function is only important for Ni-Cd batteries and unnecessary for NiMH batteries.