A battery management system protects a main contactor from inrush currents, wherein the main contactor opens and closes a charge/discharge path connected between a first battery and an electrical load before pre-charging of a capacitor provided on the side of the electrical load is completed. The battery management system double-checks whether the pre-charging of the capacitor is completed based on a voltage across the capacitor and a voltage across the main contactor. The battery management system keeps a contact of the main contactor in an open operational position when the voltage across the capacitor is less than a first threshold voltage or the voltage across the main contactor is equal to or higher than a second threshold voltage.