Can I use my old Ni-Cd battery charger to charge my Ni-MH batteries?
No, you can use a new Ni-MH charger to charge your old Ni-Cd batteries but you should not try to charge Ni-MH batteries with a Ni-Cd charger. Here’s why: Ni-MH and Ni-Cd batteries are chemically very similar and when both are fully charged, the battery voltage will start to drop. The Ni-MH voltage drop is much more subtle and more difficult to detect. Ni-MH chargers usually have an over temperature sensor and shutoff to prevent overcharge as well as a more sensitive voltage drop detector where Ni-Cd chargers usually only use the voltage drop to determine when to stop charging. If you charge Ni-MH batteries in a Ni-Cd charger, it will probably miss the voltage drop and keep right on charging causing the batteries to overheat. Overcharging and overheating Ni-MH batteries can damage them internally and reduce battery life.
