Patent ID: 7902796

Claim:
A charging method for equalization charging a battery array consisting of at least two cells, comprising the following steps: (a) charging the cells of the battery array with a constant charging current; (b) detecting the cell voltages of the individual cells to judge whether some of the cell voltages have reached a pre-set safe reference voltage; (c) repeating the step (a) when determining that none of the cell voltages has reached the safe reference voltage, or maintaining at least one of the cell voltages at the safe reference voltage and reducing the charging current at the same time when determining that said at least one of the cell voltages has reached the safe reference voltage, wherein the same charging current flows through all of the cells of the battery array; (d) judging whether all of the cell voltages have reached the safe reference voltage when the charging current is reduced to a pre-set minimum charging current; and (e) reducing the charging current continuously below the minimum charging current and then terminating the charging operation when determining that all of the cell voltages have reached the safe reference voltage, or raising the charging current suitably when determining that at least one of the cell voltages has not reached the safe reference voltage.