The present invention relates to an electrical energy regulator system for a power supply bus, the system including:an electrical energy storage unit,a solar generator having a plurality of cells,a system for regulating the bus power supply voltage adapted to impose on each cell one of the following three states:a first state in which the bus is supplied with current,a second state in which the storage unit (BAT) is supplied with current, anda third state in which the cell is shunted,the cells being divided by the bus voltage regulator system into:a first group in which at least one cell supplies power to the bus and one cell is assigned to regulation of the voltage of the bus and is in its first state only when maintaining a nominal bus voltage requires a top-up of current, anda second group in which at least one cell is either in a second state or in a third state, as a function of a required charging current of the storage unit, the number of cells in the second state being a function of the required charging current.The system further includes a system means for regulating the charging of the storage unit which assign at least one cell of the second group to supplying power to the storage unit (BAT) and one cell of the second group to regulating the voltage of the storage unit, the storage unit charging voltage regulator cell being in its second state only when maintaining a nominal charging voltage requires a top-up of current.