Abstract: A system includes a power source having multiple energy storage power cells. The system also includes multiple cell active balancing circuits. Each active balancing circuit is coupled across and associated with at least one of the power cells. Each active balancing circuit is also configured to provide energy to and draw energy from the at least one associated power cell. The system further includes an energy transfer bus configured to transfer energy between the active balancing circuits. In addition, the system includes a controller configured to control the transfer of energy between the active balancing circuits in order to control balancing of charges on the power cells. Each active balancing circuit could include a bi-directional direct current-to-direct current converter configured to convert and transfer DC energy between the associated power cell(s) and the energy transfer bus. The power source could include a battery, and the power cells could include battery cells within the battery.