No matter what kind of battery is self-discharging, so when a new rechargeable battery arrives in your hands, the rechargeable battery may have self-discharged for some time. This is that the chemical raw materials inside the rechargeable battery have not been used for a period of time, and they appear in a "passivated" state, which cannot fully exert the chemical reaction and provide sufficient voltage. In this case, when using the rechargeable battery for the first time, be sure to fully charge the rechargeable battery to restore the voltage to the original level. In fact, if your rechargeable battery has not been used for a long time, this "passivation" will also occur, and the situation will be more serious. It is best to charge and discharge the rechargeable battery three times, which will help the activation of the rechargeable battery. Let the chemicals inside the rechargeable battery give full play to its due effect (nickel-cadmium batteries). Sometimes when a newly purchased rechargeable battery is put into the charger, the charger will stop charging before it is fully charged. When you encounter this kind of problem, you just need to remove the rechargeable battery from the charger, and then put it in the charger to continue charging. This is a normal phenomenon for new rechargeable batteries, not that you have purchased bad rechargeable batteries (nickel metal hydride, lithium ion batteries). Generally speaking, the charging time should not be too long, and a maximum of 12 hours is sufficient. If it is overcharged, it will cause damage to the rechargeable battery.