Nickel-metal hydrides are environment-friendly batteries used in digital cameras and other devices that require recharging often. NiMHs are often in AA battery size and can be charged at any point, even before they are completely empty, without adverse consequences. Charging AA nickel-metal hydride batteries can be done with the proper equipment and scheduling.

 

Find out what the maximum charge capacity of the AA batteries are by reading the number labeled on the batteries followed by "mAh." Look for a similar number on the battery charger, indicating the charge rate. Check the User's Manual of the batteries or charger if you cannot find these numbers on them.

 

Estimate how long it will take to charge your NiMH batteries with a simple formula. Divide the capacity of the battery by the charge rate of the charger. Add an additional 20 percent to that time to compensate for imperfections in the equipment. For example, batteries with a charge capacity of 2400 mAh used in a charger with a charge rate of 800 mAh will ideally charge in three hours. With the additional 20 percent charge time added, the predicted total charge time will be three hours and 36 min.

 

Insert the batteries into the charger and wait for a light to turn on indicating that the charge has started. Take note of the time and be sure that you will be available at the end of the charge cycle.

 

At the end of the charge cycle, remove the batteries from the charger. Insert the batteries into a device that you commonly use. Power on the device to make sure that the batteries are charged.