Retrofit of an existing vehicle with an electric powertrain: from system design to road testing. The first part of the project, with reference to the extended V-cycle approach, consisted in testing and post processing of data coming from virtual model, semi-real prototype (test bench) and real prototype. To be more specific: a Matlab script was created in order to fulfill this purpose. A further activity consisted in the implementation of a second order thermal model of the electrical motor adopted for the retrofit kit. Starting from a publication of some other Politecnico di Torino researchers it was possible to obtain the value of the parameters needed to properly describe the time evolution of the motor temperatures.