Do you enjoy the sound of silence? Maybe you prefer the rattle of a petrol engine? Let’s consider the merits of both when we explore if electric cars make noise. In this article, we will look at the science behind the sounds of electric cars, we will look at the noises they make and why they are considered quieter than petrol or diesel vehicles.
Do electric cars make any noise?
Electric cars do make some noise when running, although they are usually quieter than the noise of the engine that is made by traditional petrol or diesel cars. EVs don’t have a loud combustion engine but they can make sound from a few sources like the electric motor, tyres, aerodynamic turbulence or even fake car sounds (yes, they really do this!).
What noises do electric cars make?
Let’s explore the list of sounds that EVs make in more detail:
- The electric motor
The electric motor in an electric car turns the electrical energy into mechanical energy to drive the wheels and make the car go! Pretty important. When the motor is going it generates a very distinctive whirring or humming sound. Unlike petrol engines, electric motors are not very loud. Instead, it’s smoother and more consistent, resulting in quieter performance.
The level of noise produced by an electric motor can sometimes vary depending on the type of motor used and how powerful it is. Some high-performance electric cars like Teslas can be louder when they accelerate. As EV technology continues to evolve, advancements in motor design, insulation, and vibration reduction can further minimise the noise produced by electric motors, making electric cars even quieter in the future.
- Noise from the tyres
This is common in all vehicle types, not just EVs. As the tyres roll over the surface of the road they will generate noise, it’s unavoidable! The best EV tyres are designed to reduce this noise using special tread patterns, however, you will hear this noise more in EVs simply because they don’t have the roar of an engine and other sounds travel through more than they might in a petrol car.
- Aerodynamic noise
Again another common feature of all vehicle types, aerodynamic noise happens as a car moves through the air. The shape, weight and design of the EV will influence the amount of aerodynamic noise made, as will the speed you are travelling.
Do electric cars have fake noise?
Electric cars do have fake noise in the UK. The government introduced regulations in 2019 to make it a requirement that all new EVs have fake noise. Due to the quiet nature of electric vehicles, especially when they are driven at low speeds, there has been a growing concern for the safety of pedestrians, cyclists, and visually impaired people who may not be able to hear the approach of an electric car.
The fake noises made by electric vehicles are not always the same, it tends to vary between manufacturers and models. Some of them are simple continuous tones, while others have designed more complex sounds that change depending on the vehicle’s speed and direction.
BMW even collaborated with composer Hans Zimmer to create a distinctive sound for their EV. The ability to customise the sound your car makes is an engaging feature for the owner.
Fake noise in EVs is not a feature that’s liked by everyone, some people have said that the artificial sounds are annoying or intrusive. As regulations spread manufacturers need to work out how to get a balance between safety and public acceptance.
Why are electric cars so quiet?
Electric cars don’t make as much noise as their petrol or diesel counterparts due to the differences in their drive systems. Here are some key reasons why electric cars are so quiet:
- No engine: Petrol and diesel car engines basically work by setting off a series of controlled explosions to generate power. EVs use electric motors that convert electrical energy into mechanical energy, as you would expect the lack of ‘explosions’ means this doesn’t make much noise. During an Electric Car MOT the technicians are not required to check for engine noise, as they would in an MOT for a petrol or diesel vehicle.
- Simpler drivetrain: Electric vehicles have a simpler drivetrain with fewer moving parts than petrol cars. There are no pistons, valves, or crankshafts that make loud noises and vibrations
- Fewer vibrations: Electric vehicles don’t vibrate as much due to the reasons mentioned above! So fewer vibrations mean less noise transmitted through the car and into the cabin
- Regenerative braking: Electric vehicles use regenerative braking, this new technology captures energy as you brake and recycles it back to the battery. This process is much less noisy than the old-style systems because no brake pads are coming into contact with each other
What are the current UK regulations on EV noise levels?
Since September 2021, the United Kingdom has adopted the European Union’s regulations on electric vehicle noise levels, which require the use of an Acoustic Vehicle Alerting System (AVAS) in electric and hybrid vehicles.
The five key parts to consider when it comes to UK regulations on EV noise levels are:
- Acoustic Vehicle Alerting System (AVAS): Electric and hybrid vehicles must be equipped with an AVAS that generates an artificial noise to alert pedestrians and cyclists of the vehicle’s presence
- Speed: The AVAS must make a noise when the vehicle is travelling at speeds below 20 km/h (12 mph) or when reversing. Above this speed threshold, the noise generated by the tires and aerodynamics is considered enough for pedestrians to hear
- The sound made: The artificial sound produced by the AVAS must be easily identifiable as car noise and should increase in pitch and volume as the vehicle gets faster
- No off-switch: The AVAS must be on at all times while the vehicle is being driven and the driver is not allowed to turn off the system
- Existing electric vehicles: Electric and hybrid vehicles that were registered before July 1, 2019, don’t need to have an AVAS installed. However, it is a good idea to consider fitting one as part of the EVs service maintenance to improve the safety of your vehicle
Do electric cars make a noise when charging?
They don’t make very much noise, but EVs are not silent when charging. You will hear a few sounds as the vehicle charges from your home EV charger:
- Contactors clicking: Contactors are high-voltage switches that control the flow of electricity between the charger and the vehicle’s battery. When you plug in the charging cable and initiate charging, you will usually hear a clicking sound as the contactors engage
- Cooling system: When an electric vehicle is charging the battery will generate a bit of heat. To prevent overheating, the car’s cooling system can kick in to regulate the temperature. This can produce a little bit of a humming noise
- Battery management system: The battery management system (BMS) is in charge of the charging process to ensure optimal battery performance and longevity. While the BMS itself doesn’t create noise, its operation may result in subtle sounds, such as low humming or buzzing, as it manages the flow of electricity.
Do EV charging points make a noise?
Generally, EV charging points are pretty quiet. The EV charging unit or station itself might make a slight humming noise as the electricity flows and other parts work, like internal cooling fans or transformers. Fast public EV chargers may make more noise than lower-output home units.
What research is being done on electric car noise?
There is a lot of research in this field that is keeping the car sector moving forward and adapting the approach to EV noise.
Several studies have been conducted to work out the best sounds that will alert pedestrians that an electric car is approaching. The trick is to find a sound that is not too loud or intrusive. These studies have involved the use of various sounds, including simulated engine noise, beeps, and chimes. As far back as 2013 the National Highway Traffic Safety Administration (NHTSA) studied the various audio options that might work with pedestrians.
In 2019, a study conducted by the University of Michigan Transportation Research Institute found that electric vehicles with fake engine sounds would lower the number of accidents involving pedestrians in comparison to EVs that make no sound.
The final word on electric car noises
Electric cars are much quieter than petrol or diesel cars, but they will still make some noise. Charging an electric car is also nearly silent, with EV chargers making a gentle hum as the electricity is transferred.
The fact that EVs are so quiet does create a safety risk to pedestrians and cyclists who are used to hearing the sound of approaching traffic on the road. Since 2019 all EVs in the UK have been required to make a simulated noise, using the Acoustic Vehicle Alerting System (AVAS) system.
While some electric car manufacturers have developed their own unique sounds for electric vehicles, regulatory bodies have also established guidelines for electric car noise to ensure we keep pedestrians safe. It is crucial to keep developing in this area to prevent accidents and promote safety on our roads.
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John is the Editor and Spokesperson for Electric Car Guide.
With over 20 years of writing experience, he has written for titles such as City AM, FE News and NerdWallet.com, covering various automotive and personal finance topics.
John’s market commentary has been covered by the likes of The Express, The Independent, Yahoo Finance and The Evening Standard.