Abstract: A battery management system for monitoring a plurality of interconnected batteries comprises a plurality of interconnected modules arranged for connection to respective ones of the batteries. Each module comprises a negative terminal connector, a positive terminal connector, a voltage sensor for measuring voltage between the terminals, a communication port arranged to communicate the sensed voltage to other modules, and a controller arranged to selectively connect a resistive element between the negative terminal connector and the positive terminal connector of the respective battery responsive to the sensed voltage being greater than sensed voltages of other modules. A temperature sensor on each module measures a temperature through the terminal of the battery for communication to the system. A printed circuit board, arranged to be supported directly on one of the battery terminals, commonly supports the voltage sensor, the temperature sensor and the communication port thereon.