A 48-volt DC electrical system voltage is a relatively low-voltage electrical system that is increasingly used in vehicles. Interest in the concept began in the 2010s as a way to increase the propulsion and battery recharge during regenerative braking for fuel savings in internal combustion engine vehicles, especially mild hybrid vehicles.

History

Traditionally, vehicle low-voltage applications were powered by a 12-volt system. In the 1990s, an attempt by a cross-industry standards group to specify a 42-volt electrical system failed to catch on and was abandoned by 2009. During the 2010s, renewed interest arose for a 48-volt low-voltage standard for powering automotive electronics, especially in hybrid vehicles.

In 2011, German car manufacturers Audi, BMW, Daimler Benz, Porsche, and Volkswagen agreed on a 48V system[clarification needed] supplementing the legacy 12V low-voltage automotive standard.

In model year 2017, the Renault Scenic dCi Hybrid Assist was the first 48V mild-hybrid passenger car.[citation needed]

As of 2018, a 48V electrical subsystem operated production vehicles such as Porsche and Bentley SUVs. Audi and Mercedes-Benz used a 48V subsystem in 2018 vehicles such as A6, A7, A8 with 3.0 TDI 48V mild-hybrid, CLS, E-Class, S-Class with M256 3.0 Turbo Otto 48V Mild-Hybrid.[clarification needed]

Hyundai Tucson, Hyundai Santa Fe, Kia Ceed and Kia Sportage followed in model year 2019 with 1.6 and 2.0 turbodiesel engines supported by 48V mild-hybrid technology.[citation needed]

A European automotive trade association, CLEPA, estimated in 2018 that as many as 1 of every 10 new vehicles in 2025 would use at least one 48-volt device in the vehicle, covering 15 million vehicles per year.

In March 2023, Tesla Inc. revealed that the Tesla Cybertruck and next-generation vehicle would utilize a 48-volt mid-voltage subsystem as a replacement of 12V system, migrating the low-voltage components with highest power demand to 48V.[bettersourceneeded]

In December 2023, in order to accelerate the adoption by other automakers of 48V system voltage for automotive components, Tesla offered a "48-volt electrical system whitepaper" to all industry leaders. CEO Jim Farley confirmed that Ford had received a copy and agreed to 'help the supply base move into the 48-volt future". Tesla also adopted 48 volts for its Optimus robot.

Benefits

A 48V system can provide more power, improve energy recuperation in hybrid systems, allow up to an 85% decrease in cable weight and 85% decrease in hardware cost.

12-volt systems can safely provide only 3.5 kilowatts, while 48V systems achieve 15 to 20kW of output, with potential for up to 50kW.[clarification needed] 48 volts is low enough to be considered safe in dry conditions without special protective measures, as it is below the generally accepted 50-volt threshold. (See the article on electrical injury)

One example of where these benefits can be used is in the Gordan Murray Automotive T.50, which uses an integrated starter-generator to power a 48V air conditioning compressor rather than using a belt. This allows the engine to rev more freely due to the reduced friction, and gives the vehicle consistent AC performance independent of engine RPM. Cars equipped with start-stop systems and using a 48-volt AC compressor will not have HVAC interruptions that belt-driven systems experience while the engine is stopped,

Autonomous driving computer systems use around 2 kilowatts when including redundancy, which would consume the majority of a typical 3.5-kilowatt 12-volt system's available power alone; 48-volt systems would alleviate these power availability concerns.

Another example is with the use of electric turbochargers, active suspension, steer-by-wire and rear-wheel steering systems that have power requirements, and can potentially be more responsive and capable with a 48V system.

See also

  • Dusan Graovac, Christoph Schulz-Linkholt, Thomas Blasius, 23 April 2020, EE Times/Asia.(subscription required)
  • ISO 21780:2020(en) Road vehicles — Supply voltage of 48V — Electrical requirements and tests[clarification needed]