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