A lithium battery pack according to the present invention has inherent information stored therein, which comprises a plurality of cells, nominal voltage, maximal voltage of the cells, range of temperature etc. A charging parameter is determined by a charging controller based on an identified data of the cells and the inherent information, and is transmitted to an adapter. A controlled module in the adapter receives the charging parameter through a control terminal and adjusts an AC/DC circuit to output a current with accurate charging voltage to the battery pack.