This paper deals with innovative multi-function battery controller with seamless transition between controllers for future MEA platforms. The battery controller performs different functions i.e. providing DC power, maintaining DC bus voltage, controlling battery voltage and battery current for charging and discharging process purposes. Due to its superiority and simplicity of implementation, the constant current-constant voltage technique is chosen for battery charging. Furthermore, the study provides a detailed analysis of the proposed approach and control challenges then proposes the corresponding solutions. The PI controller is adopted for all controllers and it was designed to provide a robust control system behaviour. Therefore, the battery terminal voltage and charging current are efficiently limited by the corresponding battery controllers. A robust Energy Management Strategy (EMS) to supervise the charging and