I have been shopping for a new car. At the Audi showroom, I was introduced to something called a 48-volt system. Apparently, Audi cars with V6 engines come with this. How does this work? Is this something that boosts power? And will it require more maintenance?

Most car electrical systems are based on a 12-volt set-up. Even on vehicles with a 48-volt system, the 12-volt network is still in use to power devices such as lights and audio.

The Audi cars you mentioned use a belt-driven alternator-starter. When the car is at the lights and its engine is turned off (as programmed by the Stop-Start system), the starting is provided by an alternator-motor that is powered by a 48-volt supply.

Essentially, a higher voltage means that the physical size of electrical wiring and motors can be reduced. More significantly, the higher voltage motors produce more torque and power. With wires of the same size and same current flow, four times the power is available.

In some cars, the 48-volt supply is used to drive active suspension control components. This is the case with active roll control motors, where high torque is necessary to resist the anti-roll bar's twist resulting in increased roll stiffness. Air suspension pumps in some cars also make use of high-voltage electrics for quicker response.

The 48-volt supply is provided by lithium-ion batteries, which are essentially maintenance-free. As for durability, there is insufficient data available at the moment to conclude just how long these batteries last.