A 48-volt DC electrical system voltage is a relatively low-voltage electrical system that is increasingly used in vehicles. It began in the 2010s as a way to increase the propulsion and battery recharge during braking for fuel savings in

internal combustion engine An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal comb ...

vehicles, especially

mild hybrid Mild hybrids (MHEV) (also known as smart hybrids, power-assist hybrids, battery-assisted hybrid vehicles or BAHVs) are generally cars with an internal combustion engine (ICE) equipped with a minimally extended battery and an auxiliary electric co ...

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 vehicle A hybrid vehicle is one that uses two or more distinct types of power, such as submarines that use diesel when surfaced and batteries when submerged. Other means to store energy include pressurized fluid in hydraulic hybrids. Hybrid powertrai ...

s.Why Cars Are Moving to 48-Volt Electrical Systems, Bill Howard April 26, 2017 https://www.extremetech.com/cars/247889-cars-moving-48-volt-electrical-systems In 2011, German car manufacturers

Audi Audi AG () is a German automotive manufacturer of luxury vehicles headquartered in Ingolstadt, Bavaria, Germany. A subsidiary of the Volkswagen Group, Audi produces vehicles in nine production facilities worldwide. The origins of the compa ...

BMW Bayerische Motoren Werke AG, trading as BMW Group (commonly abbreviated to BMW (), sometimes anglicised as Bavarian Motor Works), is a German multinational manufacturer of vehicles and motorcycles headquartered in Munich, Bavaria, Germany. Th ...

, Daimler Benz,

Porsche Dr. Ing. h.c. F. Porsche AG, usually shortened to Porsche (; see below), is a German automobile manufacturer specializing in luxury, high-performance sports cars, SUVs and sedans, headquartered in Stuttgart, Baden-Württemberg, Germany. Th ...

, and

Volkswagen Volkswagen (VW; )English: , . is a German automotive industry, automobile manufacturer based in Wolfsburg, Lower Saxony, Germany. Established in 1937 by German Labour Front, The German Labour Front, it was revitalized into the global brand it ...

agreed on a 48 V system supplementing the legacy 12 V low-voltage automotive standard. In model year 2017, the Renault Scenic dCi Hybrid Assist was the first 48 V mild-hybrid passenger car. As of 2018, a 48 V electrical subsystem operated production vehicles such as

and

Bentley Bentley Motors Limited is a British designer, manufacturer and marketer of Luxury vehicle, luxury cars and Sport utility vehicle, SUVs. Headquartered in Crewe, England, the company was founded by W. O. Bentley (1888–1971) in 1919 in Crickle ...

SUVs.

and

Mercedes-Benz Mercedes-Benz (), commonly referred to simply as Mercedes and occasionally as Benz, is a German automotive brand that was founded in 1926. Mercedes-Benz AG (a subsidiary of the Mercedes-Benz Group, established in 2019) is based in Stuttgart, ...

used a 48 V subsystem in 2018 vehicles such as A6, A7, A8 with 3.0 TDI 48 V mild-hybrid, CLS, E-Class, S-Class with M256 3.0 Turbo Otto 48 V Mild-Hybrid.

Hyundai Tucson The Hyundai Tucson (; ) is a compact crossover SUV produced by the South Korean manufacturer Hyundai. It is named after the city of Tucson, Arizona, U.S. The second-generation model was marketed as the Hyundai ix35 in several markets, includ ...

Hyundai Santa Fe The Hyundai Santa Fe () is an automobile nameplate used by the South Korean manufacturer Hyundai since 2000, specifically for a series of crossover SUVs. It is named after the city of Santa Fe, New Mexico, and was introduced for the 2001 model ...

Kia Ceed The Kia Ceed (known as the Kia Cee'd before 2018) is a compact car/small family car (C-segment) produced by the South Korean manufacturer Kia since 2006 exclusively for the European market. It is the first Kia vehicle to be designed entirely in ...

and Kia Sportage followed in model year 2019 with 1.6 and 2.0 turbodiesel engines supported by 48 V mild-hybrid technology. 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 12 V system, migrating the low-voltage components with highest power demand to 48 V. In December 2023, in order to accelerate the adoption by other automakers of 48 V 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 48 V system can provide more power, improve energy recuperation,48 VOLT: A proven technology to reduce CO2 and NOx emission, CLEPA, 2018 https://clepa.eu/wp-content/uploads/2018/01/CLEPA-48v-technology.pdf and allow up to an 85% decrease in cable mass. 12-volt systems can provide only 3.5 kilowatts, while a 48 V power could achieve 15 to 20 kW or even 50 kW. 48 volts is low enough to be considered safe in dry conditions without special protective measures. (See the article on

electrical injury An electrical injury (electric injury) or electrical shock (electric shock) is damage sustained to the skin or internal organs on direct contact with an electric current. The injury depends on the density of the current, tissue resistance an ...

.) One example of where these benefits can be used is in the Gordan Murray Automotive T.50, where it uses an

integrated starter-generator A start-stop system (also referred to as idling stop or micro hybrid) is a technology that automatically shuts down and restarts a vehicle's internal combustion engine to reduce Idle (engine), idle time, with the aim of lowering Fuel consumptio ...

to generate power for a 48 V AC compressor, without the need for a belt. This allows the engine to rev more freely and give the vehicle good AC, no matter the RPM. Another example is with the use of electric turbochargers,

active suspension An active suspension is a type of Suspension (vehicle), automotive suspension that uses an onboard control system to control the vertical movement of the vehicle's wheels and axles relative to the chassis or vehicle frame, rather than the conventi ...

, and

rear-wheel steering Steering is the control of the direction of motion or the components that enable its control. Steering is achieved through various arrangements, among them ailerons for airplanes, rudders for boats, cylic tilting of rotors for helicopters, ...

systems that require a lot of power to run, and might be more responsive and capable with a 48 V system.

References

48 V Vehicle Electrical System – More Than Just a Bridging Technology?
Dusan Graovac, Christoph Schulz-Linkholt, Thomas Blasius, 23 April 2020, EE Times/Asia. * ISO 21780:2020(en) Road vehicles — Supply voltage of 48 V — Electrical requirements and tests{{clarify, needs a URL link, date=December 2023 Electric power distribution Automotive electrics

History

Benefits

See also

References