Systems and methods for controlling an energy storage system are provided. In one embodiment, an energy storage system can include a plurality of energy storage units and a plurality of buses. The energy storage system can further include a control system that can be configured to receive one or more signals indicative of a voltage associated with each energy storage unit of the plurality of energy storage units. The control system can be configured to send one or more command signal to selectively couple each energy storage unit to one of the plurality of buses based at least on the voltage associated with the energy storage unit.