This thesis presents the development of a low voltage storage system utilizing a Gallium Nitride (GaN) Field-Effect Transistor (FET) converter. The primary objective is to design a hybrid energy storage system (HESS) that integrates a supercapacitor and a lithium-ion battery to efficiently manage power distribution between these components. The system aims to leverage the high power density of supercapacitors and the high energy density of lithium-ion batteries to optimize performance during both charging and discharging cycles. The project employs PLECS software to model and simulate the behavior of the HESS. The PLECS environment allows for detailed analysis and optimization of the power management system, ensuring efficient energy transfer and storage.