Electricity used to be minimal in automobiles. They mainly ran mechanically. Electric windows? They didn't exist. For this manually operated handles were used. Today, a whole host of electrical functions such as seat heating, comfort and assistance systems draw a lot of electricity from the battery. In a 12 V vehicle electrical system, higher and higher currents have to flow. To prevent this on-board network from surrendering, manufacturers are now installing a second, stronger network in the car in parallel – with 48 V direct current (48 VDC).