The energy efficiency of EVs is analysed for the charging and for the driving process where real parameters of a product of the automotive industry are considered. The efficiency in the charging mode is analysed and represented in function of the charging time. The maximum charging power allowed by the manufacturer is defining the lowest efficiency. After the calculation in a situation with an ideal charging station the influence of the resistance of the charging cable is taken into consideration. For the driving mode, the efficiency is estimated with the help of a special tool called “The Theory of Ragone plots”. The driving efficiency is calculated for the maximum possible propulsion power of the car, and represented in a dimensionless Ragone representation. The rated power of the car is represented in reference to the maximum possible power that can deliver the car battery.