A charging system and method is capable of starting or stopping charging a battery of a vehicle at a convenient time. A portable device and a vehicle unit can communicate with each other. A user is determined to be away from the vehicle based on a result of communication between the portable device and the vehicle unit. A charging ECU starts charging a battery when the user is away from the vehicle. Charging of the battery can be started when the user is assumed to have stopped using the vehicle and will not use the vehicle for a period of time. When the user is determined to be close to the vehicle it is assumed that use of the vehicle will be resumed at which point the system instructs the charging of the battery to be stopped. The system thereby allows the vehicle to be ready for use.