Electric Power Distribution System

An electric power distribution system which is mounted on a vehicle, supplies electric power to a main load from a first DC/DC converter and a first battery provided in parallel with the first DC/DC converter, and supplies electric power to a backup load from a second DC/DC converter and a second battery provided in parallel with the second DC/DC converter, the electric power distribution system comprising:

• a first path through which electric power is supplied from at least one of the first DC/DC converter and the first battery to the main load;
• a second path that is provided in parallel with the first path and through which electric power is supplied from at least one of the second DC/DC converter and the second battery to the backup load;
• a third path that connects the second DC/DC converter and the first battery;
• a fourth path that connects the first path and the third path and connects the first battery and the first DC/DC converter in parallel to the main load;
• and
• a control unit that controls an output voltage of the second DC/DC converter according to an assumed output capacity derived from travel route information of a navigation system mounted on the vehicle,
• wherein the assumed output capacity is a capacity that is able to supply electric power used for a driven load in the backup load at a travel point that is up to midway of a moving distance of the vehicle from a current point to a target point, and is set to be lower than a threshold battery capacity that is lower than in a fully charged state of the second battery.