ELECTRIC POWER SYSTEM FOR VEHICLE, ELECTRIC POWER CONTROL APPARATUS FOR VEHICLE, METHOD OF CONTROLLING ELECTRIC POWER OF VEHICLE, AND COMPUTER-READABLE RECORDING MEDIUM CONTAINING PROGRAM

An electric power system for a vehicle includes an exhaust heat recovery apparatus, a low-voltage system, a high-voltage system, a first wiring line, a second wiring line, and a DC/DC converter. The exhaust heat recovery apparatus includes a power generator that generates electric power on the basis of heat exhausted from a heating element. The low-voltage system includes a low-voltage secondary battery. The high-voltage system includes a high-voltage secondary battery that outputs a voltage higher than the low-voltage secondary battery. The first wiring line couples the power generator and the low-voltage system. The second wiring line couples the first wiring line and the high-voltage system. The DC/DC converter is disposed on the second wiring line and increases and decreases a voltage supplied to the DC/DC converter.