Patent ID: 8258757

Claim:
A charging method fit for use with and applicable to a rechargeable battery, the charging method being configured to charge the rechargeable battery to a first preset voltage and then charge the rechargeable battery to a second preset voltage, the charging method comprising the steps of: (a) using a first preset current as a charging current, followed by performing constant current charging of the rechargeable battery by the first preset current until the rechargeable battery reaches the first preset voltage for the first instance; (b) subtracting a current difference value from the charging current used by the rechargeable battery to reach the first preset voltage in the preceding instance so as to obtain a new charging current, followed by performing constant current charging of the rechargeable battery by said new charging current thus obtained until the rechargeable battery reaches the first preset voltage again; (c) repeating step (b) until said new charging current equals a second preset current; and (d) using the second preset current of step (c) as another new charging current, followed by performing constant current charging of the rechargeable battery by the second preset current until the rechargeable battery reaches the second preset voltage for the first instance.