Why Are Electric Cars SO Quiet? (Explained)

It can be hard sometimes to recognize when an electric car passes by because they are very quiet.

In this article, we will look into why that is, and just how quiet electric cars are today.

Why Are Electric Cars So Quiet?

The reason electric cars are so quiet is that they don’t have a combustion engine. Instead, they have an electric motor that makes very little sound. The motor only makes a very subtle humming sound that’s quieter than the noise from the wheels.

What exactly is this

Let’s find out.

Why are electric cars quieter than gas-driven cars?

Gas-driven cars all have one thing in common: they have a rather loud combustion engine that runs based on the principle of burning fuel.

This means that we have a ton of small tiny explosions inside the engine to push the pistons down in order to drive the engine.

These small explosions of gas are noisy.

The electric motor inside an electric car, on the other hand, does not have any gas or fuel to burn. It’s running purely on electricity which is a much quieter process.

You’ll find that an electric car that runs idle doesn’t make any sound. In fact, it doesn’t really run idle like a gas-driven engine. When an electric car is turned on but standing still, the motor isn’t running.

This is one of the biggest differences between electric cars and gas-driven cars.

The electric engine only runs when the car moves and this also means that an electric car is completely silent when it’s stopping at a red light.

Electric motors make very little sound

The electric motor doesn’t have any noisy parts. In fact, they are incredibly simple machines that rotate due to electric current and magnetic fields.

In other words, you will be able to run a motor almost completely silently.

The reason you CAN hear electric cars is that the tires make noise when rolling over the road as well as the wind resistance will make you notice the car.

Read on to hear why this fact actually means that electric cars aren’t quieter than regular gas-driven cars when they go at higher speeds.

How many decibels are electric cars?

An electric car will make around

In many countries and states, electric cars are required to make a sound around them. This means, that electric cars need to produce an artificial sound through a speaker system positioned outside the car.

When an electric car is turned on without driving, it will produce sound at around 40 Db.

This is equivalent to:

  • A refrigerator
  • Quiet library
  • a fan
  • etc.

At highway speed (60-70 mph) an electric car will make around 80-90 Db, which is equivalent to these sound sources:

  • A big hairdryer
  • Vacuumer
  • A normal gas-driven car

It may come as a surprise that electric cars aren’t quieter than regular gas-driven cars when they drive at higher speeds.

Are electric cars quieter on the highway?

Electric cars are not quieter than gas-driven cars on the highway. This is because the majority of the noise from both electric cars and normal gas-driven cars doesn’t come from the engine or the motor but from the tires and the wind resistance.

This is actually quite surprising and I was also surprised to find this during my research for this article.

I thought an electric car would be significantly noisier than it’s gas-driven cousins, but that’s just not true.

I remember taking a Nissan Niro for a spin and I noticed that it wasn’t very quiet on the road – now I know why!

When you drive an electric car on the highway you will mostly hear the tire noise and the wind noise. Not much else. This also means that the cabin can be quieter.

What electric car is quietest inside the cabin?

Here we have to turn to the good old American company Ford.

Ford has made an electric (actually a PHEV) Ford Escape which is equipped with noise-reducing acoustic glass. So they call it.

I happened to know a guy that owns a big Mercedes and a Ford Escape with noise-reduced glass on the front and sides. He told me that the Ford Escape (called “Kuga” in Europe) is actually a lot less noisy than his big expensive Mercedes!

The acoustic glass material is made in a way that it keeps the wind noise out and when you add extra padding in the doors and around the motor and engine, you get an incredibly quiet cabin!

Take the Ford Escape for a spin the next time you get a chance and ask for one of the models with noise-reducing acoustic glass installed!

What sound does an electric car make?

You probably recognize the sound if you live in the city.

It sounds like a symphony of space sounds as there are multiple frequencies played at the same time. Click this video to hear what it sounds like:

This subtle noise sounds almost like a spaceship for many electric and hybrid cars.

These cars have a very spacy sound:

  • Nissan Leaf
  • Nissan Qashqai (PHEV)
  • Renault Zoe
  • Audi E-tron models

This sound is mandatory in most countries and more countries are joining as I write this article.

Electric cars are required to make a sound so the car companies have chosen a very futuristic soundscape that has nothing to do with the sound of normal combustion engines.

What electric cars are the quietest?

The Norwegian Bjørn Nyland has done some extensive testing on electric cars. He has measured over 30 electric cars and here’s the top5 list he found to be the quietest EVs:

These are the five quietest electric cars:

  1. Audi E-Tron (60 Db)
  2. Mercedes EQS (61.4 Db)
  3. Tesla Model X (63 Db)
  4. Jaguar I-Pace (63 Db)
  5. Mercedes EQC (63.5 Db)

The test was done at 50 mph (80 kilometers per hour) which is a normal driving speed in most states and you’ll notice that these cars are actually much quieter than a normal gas-driven car.

A gas-driven car will make around 70 Db when driving at the same speed. It may not sound like much of a difference but you need to understand that the Db (decibel) scale isn’t linear – it’s logarithmic.

When you add 10 Db you actually 10X the noise level!

This means that the noise level increases rapidly with just a few Db!

It’s worth noting that the Mercedes company actually has two spots on this list!

Here is the winner: The Audi E-Tron:

What electric cars are the noisiest?

Similarly, we can look at which electric cars are makes the most noise.

These are the loudest electric cars:

  1. Maxus E-deliver 3 (70.9 Db)
  2. Honda E (69.7 Db)
  3. Peugeut e-208 GT (69.4 Db)
  4. Lexus UX 300e (68.9 Db)
  5. Fiat 500e (68.6 Db)

Again, the test was done at 50 mph (80 kilometers per hour).

It’s interesting to see that the smaller cars top the list. The Maxus is quite spacious but the Honda E, the Peugeot, and the Fiat 500 are really small city cars.

This emphasizes our finding from before, that it’s actually not the motor itself (or the size of it) that makes the sound – but the tires and the wind resistance.

You’ll see that the Maxus isn’t very sleek and aerodynamic. It’s actually a commercial van which means that the wind is not distributed smoothly around the edges of the car to reduce the noise.

Are electric cars TOO quiet?

As we touched on, many countries and states have made laws that require electric cars to produce some noise when driving. This is actually to protect the pedestrians and cyclists around the cars.

It can be really dangerous to have an almost silent car creating up on you if you cannot hear it at all.

Especially for blind people.

That’s the reason electric cars are required to make some noise, and it’s also the reason you hear a very spacy sound from many electric cars as they don’t want to contribute to the traffic noise you hear from cars with engines.

Sources:

https://www.edmunds.com/car-news/audi-e-tron-review.html

https://www.audi.com/en/company/sustainability/core-topics/products-and-services/light-and-sound.html

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