There is provided a Lithium-Sulfur battery management system for determining a state of charge of a Lithium-Sulfur battery (LS1). The management system comprises a first circuit having at least one reactive element (Cb), and the first circuit is configured to discharge and charge fixed amounts of charge from and to the battery (LS1) via the at least one reactive element (Cb). The management system also comprises a second circuit (DA1, MC1) for monitoring the discharging and charging, and the second circuit is configured to measure the discharge time and the charge time of the fixed amounts of charge, and determine the state of charge based on those times. There is further provided a method for determining the state of charge of the Lithium-Sulfur battery.