A system for balancing a battery assembly and related methods for making and using same are provided. The system can obtain a status of a battery assembly with a plurality of batteries. One or more of the batteries can be selected based on the obtained status, and the selected batteries can be balanced. The system, for example, can control active balancing of the selected batteries when the battery assembly is in a static state and control selective discharging of the selected batteries when the battery assembly is in a discharging state. When the battery assembly is in a charging state, selective charging of the selected batteries can be controlled. One or more cells that comprise the individual batteries alternatively can be selected for balancing. A protective circuit can help ensure safety of the balancing. Battery balancing can be energy-efficient and time-efficient. The lifetime of the battery assembly can be extended.