A protected system for controlling power transactions for an electric vehicle provided with a box enclosing a battery, a battery management system, a vehicle management unit, and a bus between the vehicle management unit and the battery management system, the protected system comprising: identification modules (30, 32) respectively integrated to the box and the battery management system, providing identification information of the box and the battery management system; a set of integrity sensors of the box and of the battery having readable states; an integrity monitoring module connected to the integrity sensors, producing information indicative of the states of the integrity sensors; a device identification module for identification of devices connected to the bus; a processing module for processing information produced by the battery management system, the vehicle management unit, the integrity monitoring module, the device identification module, the processing module having: a memory storing data indicative of technical characteristics of the battery, and event, transaction and energy data deriving from preestablished selective processings of the information received as a function of the technical characteristics of the battery; and a calculation unit determining an energy balance as a function of the event, transaction and energy data; and a communication module having a mode of transmission of a warning in case of an imbalance in the energy balance and in case of an integrity breach revealed by the data stored in the memory of the processing module. identification modules (30, 32) respectively integrated to the box and the battery management system, providing identification information of the box and the battery management system; a set of integrity sensors of the box and of the battery having readable states; an integrity monitoring module connected to the integrity sensors, producing information indicative of the states of the integrity sensors; a device identification module for identification of devices connected to the bus; a processing module for processing information produced by the battery management system, the vehicle management unit, the integrity monitoring module, the device identification module, the processing module having: a memory storing data indicative of technical characteristics of the battery, and event, transaction and energy data deriving from preestablished selective processings of the information received as a function of the technical characteristics of the battery; and a calculation unit determining an energy balance as a function of the event, transaction and energy data; and a memory storing data indicative of technical characteristics of the battery, and event, transaction and energy data deriving from preestablished selective processings of the information received as a function of the technical characteristics of the battery; and a calculation unit determining an energy balance as a function of the event, transaction and energy data; and a communication module having a mode of transmission of a warning in case of an imbalance in the energy balance and in case of an integrity breach revealed by the data stored in the memory of the processing module.