A battery pack control module for balancing a plurality of cells or groups of cells connected in series includes a controller assembly, a disconnect circuit, a pack sensing circuit, a balancing circuit, and computer instructions for instructing the controller assembly to control the disconnect circuit and the balancing circuit. The disconnect circuit engages the controller assembly and a plurality of cells or groups of cells connected in series. The pack sensing circuit connects to the controller assembly and the plurality of cells or groups of cells connected in series. The balancing circuit connects between the plurality of cells or groups of cells connected in series, and engages the controller assembly. The plurality of cells or groups of cells connected in series is balanced when the battery pack control module operates in a charging phase, a discharging phase, a quiescent phase, or a storage phase.