A battery pack includes a first parallel cell group, a second parallel cell group, a first passive balancing circuit, a second passive balancing circuit, and a balancing controller operatively coupled to the first and second passive balancing circuits positioned to control the first and second switches. The balancing controller may measure a voltage of the first parallel cell group and second parallel cell group, provide a pulse-width modulated signal to the first switch with the balancing controller to control the first switch, and dissipate stored energy from the first parallel cell group through the first load resistor.