A load control system (100, 200, 300, 400), adapted to be connected to at least one first battery and at least one second battery and to control a load (20, 20') to switch between a first state, in which two connecting wires of the load are open-circuited, and a second state, in which the wires of the load are short circuited, wherein the load (20, 20') is powered by an independent power supply; the load control system comprising: a power switching device (30, 31, 44), including a first power input port, a second power input port and a power output port, wherein the first power input port is configured to be electrically connected to the at least one first battery and the second power input port is configured to be electrically connected to the at least one second battery; the power switching device (30, 31, 44) is controllable to switch between a first switching mode and a second switching mode, wherein the first power input port and the power output port are in conduction with each other in the first switching mode, and the second power input port and the power output port are in conduction with each other in the second switching mode; and a control device, electrically connected to the power output port to receive the power supplied from the power output port to operate; wherein the control device is configured such that, when the control device operates to receive a control signal, which is generated by a control interface operated by a user, the control device controls the load (20, 20') to switch from one of the first state and the second state to the other one according to the received control signal, and meanwhile controls the power switching device (30, 31, 44) to switch from one of the first switching mode and the second switching mode to the other one; wherein the power supplied from the power output port is supplied to the control device; wherein the power switching device (30, 31, 44) further includes a relay (30a, 31a) which includes the first power input port, the second power input port and the power output port; characterised in that the relay (30a, 31a) further includes a control port which includes two contacts (381, 382) configured to be electrically connected to the two connecting wires (21, 22) is of the load respectively; in the first switching mode, the two contacts (381, 382) are either short-circuited or open-circuited, and in the second switching mode, the two contacts (381, 382) are another one of being open-circuited or short-circuited. a power switching device (30, 31, 44), including a first power input port, a second power input port and a power output port, wherein the first power input port is configured to be electrically connected to the at least one first battery and the second power input port is configured to be electrically connected to the at least one second battery; the power switching device (30, 31, 44) is controllable to switch between a first switching mode and a second switching mode, wherein the first power input port and the power output port are in conduction with each other in the first switching mode, and the second power input port and the power output port are in conduction with each other in the second switching mode; and a control device, electrically connected to the power output port to receive the power supplied from the power output port to operate; wherein the control device is configured such that, when the control device operates to receive a control signal, which is generated by a control interface operated by a user, the control device controls the load (20, 20') to switch from one of the first state and the second state to the other one according to the received control signal, and meanwhile controls the power switching device (30, 31, 44) to switch from one of the first switching mode and the second switching mode to the other one; wherein the power supplied from the power output port is supplied to the control device; wherein the power switching device (30, 31, 44) further includes a relay (30a, 31a) which includes the first power input port, the second power input port and the power output port; characterised in that the relay (30a, 31a) further includes a control port which includes two contacts (381, 382) configured to be electrically connected to the two connecting wires (21, 22) is of the load respectively; in the first switching mode, the two contacts (381, 382) are either short-circuited or open-circuited, and in the second switching mode, the two contacts (381, 382) are another one of being open-circuited or short-circuited.