Present paper presents an approach for designing of regenerative braking system for human powered vehicles such as bicycle. Existing regenerative braking system is robust and its application is limited to fuelled vehicles only. Keeping size and weight constraints in mind, a lucid mechanism that incorporates a flat spiral spring, planetary gear system and a one-way clutch as the main components, is investigated here as regenerative braking system. This system stores the kinetic energy in the form of elastic potential energy and converts it back to kinetic energy. The design setup is pliable and can be incorporated with ease on a wheel hub. The mechanism is capable to work in extreme conditions. This system will prove to be cogent in assistance to the driver while acceleration, thus enhancing the overall efficiency of the system. © 2021 Author(s).