48 volt systems

We expect a lot from our cars. We also expect an elevated level of service for them, as an indispensable part of our lives that we often spend more with than our own families. State-of-the-art features, advanced handling and concierge level services like mobile tyre fitting are now the norm. Demands on the specification of the cars themselves have put pressure on manufacturers to innovate, and explore how to achieve more in a cost-effective and energy efficient way. Here, we look at the 48-volt electrical systems, and the ways in which we’re seeing manufacturers improve the performance and specification of their cars.

A shift to 48-volt systems

While the technology itself isn’t new, car manufacturers like Audi have been driven to emphasise production. Pressures to meet stringent emissions targets along with greater power requirements for obligatory features. Experts predict the new format will be a feature of a fifth of all new cars by 2025.

Emissions and Features

These 48-volt systems have opened a range of possibilities to manufacturers, with interesting innovations emerging as a result. For many, emphasis has been on upgrading traditional mechanically-driven components such as the power steering, brake vacuum pumps and water pumps, to electrically powered parts that are more efficient.

In-car entertainment, information and driver assistance are becoming increasingly complex, with improvements to features like adaptive cruise control, hands-free parking and blind spot monitoring, while the obligatory heated seats, steering wheels and windshields are still in high demand. 12-volt systems are now less able to keep up with power demands as a result.

Powering Better Performance and Handling

Use of a 48-volt battery has numerous possible applications for performance as well as for powering modern conveniences. It is used in the Bentley Bentayga to power an electric sway bar system, which improves handling; while other manufacturers like Delphi and Audi, use it to power an electric supercharger. The Delphi branded version, the E-charger, features in the Honda Civic to boost turbo in stop/start events, and to smooth out low RPM torque issues

‘Light’ Hybrids

The growing popularity of the 48-volt system does not necessarily make the 12-volt battery obsolete. The 48-volt system is largely expected to be combined with 12-volt designs as a hybrid, with the new electric motor and battery added to the combustion engine and normal 12-volt battery. The 48V system in the Renault Scenic consist a Belt Alternator Starter (also called a Motor Generator Unit, or MGU), a DC-to-DC converter, and a higher voltage battery.

The alternator, or MGU replaces the traditional alternator. This ‘light hybrid’ results in a cheaper, lighter alternative to a full hybrid, with fuel economy improvements of about 10 to 15 percent.

Each country has its own CO2 emissions targets for combating climate change, which impact regulations on fuel economy. Fuel economy is becoming more of a priority for manufacturers as a result, particularly in the EU and China, which each expect 117 grams of CO2 per kilometer by 2020. 

Cause for demand

Overall, the conditions driving the switch to 48 volts can only bring advantages to the customer. Reduced engine load, powerful accessories, a smoother journey, and better fuel economy are just a few of the benefits entering the new car market, although with around 14 million 48-volt mild hybrids expected to enter production by 2025, most the population may have to form an orderly queue.