A storage-battery control system comprising: a storage battery unit constituted by a plurality of battery modules to output a predetermined high voltage value; a controller; and an insulating communication unit configured to couple the storage battery unit and the controller, wherein each of the plurality of battery modules includes a secondary battery, and a module-side insulating circuit coupling to the insulating communication unit, the controller includes a low voltage power supply unit; and the controller detects a discharge-target battery module based on module voltages of the plurality of battery modules; characterized in that the controller further includes a controller-side voltage converter for converting a voltage of the low voltage power supply unit into a controller-side predetermined operation voltage value, and a controller-side insulating circuit coupling to the insulating communication unit, each of the plurality of battery modules includes a power supply path switching circuit (62, 69, 89) configured to switch between a path for supplying electric power to a predetermined module-side circuit element in the battery module from the secondary battery of the battery module and a path for supplying electric power output from the controller-side voltage converter, and the controller, on the discharge-target battery module, configured to urge the power supply path switching circuit to supply electric power from the secondary battery to the predetermined module-side circuit element, while, on each of the plurality of battery modules other than the discharge-target battery module, configured to urge the power supply path switching circuit to supply electric power output from the controller-side voltage converter to the predetermined module-side circuit element. a storage battery unit constituted by a plurality of battery modules to output a predetermined high voltage value; a controller; and an insulating communication unit configured to couple the storage battery unit and the controller, wherein each of the plurality of battery modules includes a secondary battery, and a module-side insulating circuit coupling to the insulating communication unit, the controller includes a low voltage power supply unit; and the controller detects a discharge-target battery module based on module voltages of the plurality of battery modules; characterized in that the controller further includes a controller-side voltage converter for converting a voltage of the low voltage power supply unit into a controller-side predetermined operation voltage value, and a controller-side insulating circuit coupling to the insulating communication unit, each of the plurality of battery modules includes a power supply path switching circuit (62, 69, 89) configured to switch between a path for supplying electric power to a predetermined module-side circuit element in the battery module from the secondary battery of the battery module and a path for supplying electric power output from the controller-side voltage converter, and the controller, on the discharge-target battery module, configured to urge the power supply path switching circuit to supply electric power from the secondary battery to the predetermined module-side circuit element, while, on each of the plurality of battery modules other than the discharge-target battery module, configured to urge the power supply path switching circuit to supply electric power output from the controller-side voltage converter to the predetermined module-side circuit element.