A power management method includes measuring the voltage and the current of a power source, an electrical output and a battery. The power generated by the power source, the power consumed by the electrical output and the power exchanged with the battery are calculated. The power source, the electrical output, the battery and the electrical grid are connected. Measurements of electrical generation and information on the consumption and control possibility of one or more remote systems are transmitted to a monitoring device. The electrical output is connected to the power source, the battery or the electrical grid according to information on the tariff per kWh provided by the public electricity grid, such as peak and off-peak time.