The International Automobile Federation (FIA) over the last few years consistently implements the strategy of introducing hybrid and electric drivetrains to all motorsport competitions. The article discusses the implementation of a hybrid drivetrain system powered by 48V for such FIA rally cars groups like Rally2, Rally3 and Rally4 based on current discussions held at the FIA Technical Working Groups. The implementation of hybrid drive systems in rally cars was analysed in terms of their advantages and disadvantages. In the case of this application the important aspect is the assumption regarding an increase in performance, while keeping a high level of safety and reasonable costs. Additionally, the assumption is to reduce the emissions of harmful substances produced by rally cars. The article concludes selection of elements of the above-mentioned system for further reasearch were presented. An analysis and calculations of the energy recoverable from regenerative braking using the BISG on a given section of the rally were carried out. Conclusions were also drawn regarding further work that will be carried out to successfully implement the above-mentioned systems for rally cars.