In the present paper the electro-mechanical model of an electric vehicle suitable for battery energy management systems has been presented. In order to verify its accuracy, the comparison between the experimental and simulation results has been carried out. Particularly, the energy battery estimation of a Smart Fortwo electric vehicle has been developed. The electro- mechanical model describing the vehicle dynamic, the power- train and the transmission system have been implemented in the Matlab environment. Moreover, a detailed battery model has been introduced in order to represent accurately its static and dynamic behavior. To verify the matching of the electric vehicle model under critical energy conditions, corresponding to rapid speed changes, the experimental data of two no-standard driving paths has been collected. The comparison of the estimated battery parameters with the experimental ones has been finally reported highlighting a good matching between them.