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. [1]
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. [2] During the 2010s, renewed interest arose for a 48-volt low-voltage standard for powering automotive electronics, especially in hybrid vehicles. [3]
In 2011, German car manufacturers Audi, BMW, Daimler Benz, Porsche, and Volkswagen [4] agreed on a 48 V system[ clarification needed ] supplementing the legacy 12 V low-voltage automotive standard. [5]
In model year 2017, the Renault Scenic dCi Hybrid Assist was the first 48 V mild-hybrid passenger car.[ citation needed ]
As of 2018, a 48 V electrical subsystem operated production vehicles such as Porsche and Bentley SUVs. Audi and Mercedes-Benz 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. [6] [ 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 48 V 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. [7]
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. [8] [ better source needed ]
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". [9] Tesla also adopted 48 volts for its Optimus robot. [9]
A 48 V system can provide more power, improve energy recuperation in hybrid systems, [7] and allow up to an 85% decrease in cable mass. [10]
12-volt systems can safely provide only 3.5 kilowatts, while 48 V systems achieve 15 to 20 kW of output, with potential for up to 50 kW.[ 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. [11] (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 48 V 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. [12] 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. [11]
Another example is with the use of electric turbochargers, active suspension, and rear-wheel steering systems that have power requirements, and can potentially be more responsive and capable with a 48 V system. [13]