Universal rapid chargers work with standard AA batteries, as well as AAA, C, D, and 9V. Such materials as Ni-Cd, Ni-MH and rechargeable alkaline manganese are compatible with these chargers, as are alkaline batteries.
Before inserting the batteries into the charger, it's important to adjust the switches on the machine to the correct setting for the type of battery. The charging mechanism works differently depending on the battery type. The charging time varies with material and size. Some Amazon.com reviewers report that leaving the battery in the charger overnight, rather than taking it out as soon as the light turns green produces a longer lasting charge.