Charging time (hours) = coefficient of rechargeable battery capacity (mAh) / charging current (mA) * 1.5 If you use a 1600mAh rechargeable battery and the charger charges with 400mA, the charging time is: 1600/400 * 1.5 = 6 hours (Note: This method is not applicable to newly purchased or long-term unused rechargeable batteries.) Ni-MH rechargeable batteries and lithium-ion rechargeable batteries actually have memory effects. Do they really need to be discharged when used? In fact, the memory effect of nickel-metal hydride rechargeable batteries and lithium-ion rechargeable batteries is very slight, and it is not worth our attention. (Please note that when you see this, do not use the discharge function of the charger to discharge Ni-MH rechargeable batteries and lithium-ion rechargeable batteries. Especially lithium-ion rechargeable batteries, due to their own material factors, do not allow the battery itself to withstand Forced discharge of the charger. If you have to discharge the lithium-ion rechargeable battery, it will eventually cause damage to the battery.) In addition, you use a nickel-cadmium rechargeable battery that needs to be discharged. It is good to charge and discharge the nickel-cadmium rechargeable battery every two or three months, so that the memory effect of the nickel-cadmium rechargeable battery can be minimized.