The purpose of this project consists in the creation of a development’s process for the retrofit of different conventional combustion vehicles with an electric powertrain. Following the rules of the Model-Based Design and of the V-cycle for software development, a model has been created in MATLAB/Simulink. This model takes the name of Virtual Prototype, and his creation is fundamental for the choice of the powertrain’s components and how they must interact with the VMU (Vehicle Management Unit). The model is validated following the V-cycle that let an easier comparison between the virtual prototype, the semi-real prototype (where powertrain components are mounted on a test bench), and the real prototype (the retrofitted vehicle).