ON-VEHICLE ELECTRIC POWER CONTROL SYSTEM, CONTROL DEVICE, AND AGGREGATED CONTROL DEVICE

The influence of a power supply voltage drop due to a wire diameter reduction of a wire harness is suppressed, and the operation guarantee voltages of components to connected to the wire harness are appropriately secured. An on-vehicle electric power control system includes a low-voltage battery , a first control device , and components to . The first control device acquires wiring resistance values of power supply lines of a third power supply line , a fourth power supply line , and a fifth power supply line , acquires a current value supplied to the components to , and calculates a voltage drop amount in the power supply line based on the acquired wiring resistance value and current value. Then, a correction value for correcting the output voltage of the DC-DC converter is determined based on the calculated voltage drop amount, and a correction request indicating the determined correction value is transmitted to a second control device