A battery management system includes a monitoring circuit and a charger. The monitoring circuit is operable for monitoring a battery pack that includes a plurality of cells, and for checking an unbalanced condition of the battery pack in each cycle of a plurality of cycles. The charger is operable for controlling a charging current to the battery pack and for receiving monitoring information from the monitoring circuit, and for adjusting the charging current from a first level in a previous cycle to a second level that is lower than the first level in response to a detection of the unbalanced condition in a current cycle.