NiCd rechargeable battery is characterized by high efficiency current-carrying capacity, but there are disruptive effect on memory. Should be unloaded and loaded in the full cycle, ie, it is recommended to fully discharge, and after unloading must charge the battery immediately without leaving it for a long time in a discharged state.
NiMH batteries have a higher self-discharge over time and shorten the life - on the other hand, they earn about 30% more capacity.