The invention relates to a regulation system for voltage regulation in the electrical power supply system for a motor vehicle, which contains a supercapacitor. In a short-term standby mode (ST), the voltage (U) of the supercapacitor is regulated such that a voltage window (U) is maintained, thus ensuring a minimum energy content in the supercapacitor (4). During a long-term standby mode (LT), the supercapacitor (4) is charged to a voltage (U_h) only when an activation signal (t_A) occurs. The energy for charging is drawn from a second energy store, in particular a battery.