Charging faster than 16 hours at 10% or discharging faster than 5 hours at 20% will result in lowering the capacity possibly significantly. Only special Rapid Charge or High Rate Discharge cells can hand that. NiMH batteries can be charged or topped-off at any time without affecting battery life. During storage NiMH batteries will lose some voltage and may arrive at less than 1V. Fully charge them at 10% of the capacity for 16 hours before use so as to bring them back to a full rating. In order to achieve optimum performance from NiCd batteries, they must be fully discharged before recharging. Unlike NiCd batteries, NiMH has No Memory Effect. NiMH batteries have no Cadmium added. Cadmium is hazardous to the environment.