Can a NiMh Charger Charge a NiCd Battery?

Successfully charging a NiCd battery with a NiMh battery charger will depend on the type of NiMh battery charger you are using. There are 2  common types of nickel metal hydride battery chargers: timer and smart chargers.

Timer

Timer type battery chargers are prolific because they are simple to engineer and inexpensive to manufacture. Because nickel metal hydride batteries have a higher capacity than nickel cadmium batteries, NiMh chargers use a longer charge cycle. This compensates for the higher capacity to completely charge your NiMh battery. NiCd batteries can experience damage from over chargeing if left on a timed charge set for  the longer NiMh cycle. Some timed chargers have adjustable timers to accommodate different battery types.

Smart Charger

Batteries have very dynamic electrical properties. Smart battery chargers analyze the electrical properties of the battery at the moment it is placed in the charger. Than the smart charger selects a charge profile best suited for the occasion. A nickel cadmium battery placed in a smart charger designed for standard nickel hydride batteries probably would not be harmed and would charge just fine.

To maximize battery longevity, use a battery charger that matches the ideal charge characteristics of your battery.