POWER SUPPLY SYSTEM FOR VEHICLE AND CONTROL METHOD

An object is to provide a power supply system for a vehicle and a control method for the power supply system that make it possible to securely start the vehicle even in a state where there is a higher possibility that a user does not perform maintenance on the vehicle. A power supply system includes a charging controller, in which, when a soak time representing a period of time elapsed after an off operation has been received is shorter than a first period of time that is determined beforehand, a coupling state detector has detected that there is coupling between an external power supply and an on-vehicle charger, and a remaining amount in a low voltage battery is equal to or below a predetermined remaining amount, the charging controller causes the low voltage battery to be charged with electricity.