Embodiments of the disclosure provide a battery management system (BMS) including: a first controller monitoring a first battery cell array having at least one battery cell and configured to measure an operating parameter of the first battery cell array; and a second controller monitoring a second battery cell array having at least one battery cell and configured to measure an operating parameter of the second battery cell array, and communicatively coupled to the first controller. The first controller is selectable between: an active mode for receiving the measured operating parameter of the second battery cell array from the second controller, and detecting a fault in the first or the second battery cell array based upon the measured operating parameters thereof, and a passive mode for measuring the operating parameter of the first battery cell array, and transmitting the measured operating parameter to the second controller.