Probably a 1st year apprentice question, but can you substitute a NiCd battery of the same voltage/capacity in place of a NiMh without creating charging problems?
Although they are both charged with constant current , the requirements are different, and NiMh are more sensitive to overcharge, and should not be trickle charged at the same rate.
Although they are both charged with constant current , the requirements are different, and NiMh are more sensitive to overcharge, and should not be trickle charged at the same rate.