A power source control device that includes: a make-and-break relay configured to either make or break conduction between a first terminal of a load and a first electrode of a direct current power source; a dark current generation circuit configured to generate a dark current by lowering a voltage of the direct current power source, in a state in which a first terminal is connected to the first electrode of the direct current power source and a second terminal is connected to the first terminal of the load so as to be parallel to the make-and-break relay; and a bypass circuit configured to dissipate some of power supplied from an external charger by making conduction between a second electrode of the direct current power source and the first terminal of the load in response to the direct current power source being charged by the external charger.