2019 Ram 1500 with a 48-volt system

Automakers worldwide increasingly talk about electrifying their fleets, but it doesn’t mean every future car or truck will need to be plugged in. Instead, the first wave of this advance is 48-volt technology.

The new onboard battery systems can provide extra juice to run infotainment and advanced safety systems that are increasingly complex and thirsty for power. Other benefits include decreased emissions and even improved acceleration.

Experts tell CR that 48-volt systems are an easy way for automakers to improve performance, fuel economy, and even durability.

Why 48-Volt?

Most cars today contain the typical 12-volt electrical system that relies on an alternator to convert the engine’s power into electrical current. That current charges the vehicle’s starter battery and runs all the vehicle’s electrical components, including lighting, infotainment, and safety systems.

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But 12-volt systems are becoming inadequate for modern vehicles, says Sam Abuelsamid, a senior analyst at Navigant.

“We’ve got so many things in the vehicle today that are demanding electrical power,” he says, from advanced safety technology to convenience features.  

That’s why automakers including Fiat Chrysler Automobiles (FCA), Mercedes-Benz, and Volkswagen have started designing vehicles using 48-volt systems, which CR calls mild hybrids. The technical changes are relatively minor. Cars get an electric generator instead of an alternator, and a larger battery and regenerative brakes.

Why are they making the change? Because a 48-volt system can save fuel, reduce emissions, and increase power, which helps automakers meet stricter worldwide fuel economy and emissions standards without sacrificing performance. Beyond the power boost and fuel savings, 48-volt systems don’t add as much up-front cost as true hybrids, such as the Toyota Camry Hybrid.

"The addition of 48-volt batteries can be good value for consumers because they support the latest tech features and boost fuel efficiency at a reasonable price point,” said Shannon Baker-Branstetter, senior policy counsel for energy and environment at Consumers Union, the advocacy division of Consumer Reports.

For example, a 48-volt system comes standard on the 2019 Ram 1500 outfitted with the smaller 3.6-liter engine. It adds only $800 to a Ram equipped with the larger 5.7-liter V8 engine, and it can boost fuel economy up to 10 percent, FCA says. It also adds up to 130 lb.-ft. of torque, which translates into better initial acceleration and more power for hauling and towing.

48-volt system in a Ram 1500 chassis
The chassis of a 2019 Ram 1500, showing its 48-volt system.

The 48-volt battery system allows the 2019 Audi A6 to shut off its engine while coasting to save fuel. The setup also makes the car’s auto stop/start function—which shuts off the engine when the car is stopped—much less intrusive. The engine restarts faster and the air conditioning stays on while the engine is off, which addresses a common consumer complaint.

“Ultimately, the biggest change in performance I think the U.S. consumer is going to appreciate is the feel of the engine start-stop performance,” says Brian McKay, director of powertrain technology and innovation for Continental North America, which supplies Audi with its 48-volt system. According to McKay, Continental’s system adds only about 33 pounds to the weight of the vehicle.

Consumers will also see a vehicle’s electric-powered convenience features perform better, McKay says, with the vehicle “being able to warm up your seats faster, defrost your windshield faster.” A 48-volt system will also provide enough amperage to run power tools, which is a feature McKay expects to see used on pickup trucks. Already, FCA says the Ram 1500 can provide up to 400 watts of power.

2019 audi a6 interior
The Audi A6 uses a 48-volt system, which promises smoother start-stop and more power for high-tech features.

A 48-Volt Future

Drivers should expect even more 48-volt advances soon. “Once you have a 48-volt infrastructure available in your car, you can start doing some interesting things with it,” McKay says.

Audi already uses the 48-volt system in its A8 sedan to power small electric motors in its adaptive suspension. In Europe, the 48-volt 2018 Audi SQ7 TDI uses an electric compressor to help its twin turbochargers work faster and better, improving acceleration.

A 12-volt electrical system just wouldn’t have enough juice to power these systems, Abuelsamid says. That’s also the case with the energy-hungry sensors and computers necessary for the next generation of autonomous vehicle technology.

In the near future, he expects more belt-driven engine components—like water pumps and radiators—to get electrified as 48-volt systems become more commonplace.

“They should also be more reliable in the long term, because they’re not dependent on that belt,” he says. Because electrical systems often have fewer moving parts than traditional approaches, they have been found to be more reliable over time.

According to McKay, the 48-volt system itself shouldn’t cause any maintenance headaches. The whole system, including the battery, “will last the lifetime of the vehicle,” he says.

We are eager to put those claims to the test when we purchase a Ram 1500. As for reliability, we will see what CR members say in future surveys.