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What is an electric car and how do electric cars work?

April 24, 2020 by

There’s a huge buzz (sorry!) around electric cars right now, and with legislation regularly being introduced that encourages people towards electric motoring, it won’t be all that long until we’re all driving them.

But although you might like the idea of electric vehicles, you may still be in the dark over the nuts and bolts of how they actually work. What are the key components? How does driving one differ from the cars we’re used to? How dependable are they? We’ll answer all these questions and more in the advice guide below.

How do electric cars work?
Electric motors
Electric car batteries
Are electric cars automatic?
Are electric cars reliable?
How long do electric car batteries last?
Should I buy a used electric car?
What electric cars have/don’t have


What is an electric car?

Simply, an electric car is a car that is powered by one ore more electric motors. The motor is powered by rechargeable batteries that are placed in a pack or stack, usually under the floor of the car.

Electric cars are different from hybrid cars and plug-in hybrid cars as they do not have a petrol or diesel engine whereas hybrids do.

You might see the term EV – this stands for electric vehicle and covers cars, vans, buses etc powered by electricity.

To recharge an electric car’s batteries you have to plug the car into either a wall charger installed at your home or at a network of public charging sites around the country.

Electric cars are growing in popularity as they don’t have any tailpipe emissions. They don’t emit CO2 or particulates, unlike petrol or diesel cars. These emissions are said to contribute to global warming and harm air quality, especially in urban areas.

Electric motors

One of the key components in every electric car is the motor. This is the thing that drives the wheels, which makes the car go along. You could say that it’s the equivalent of the engine in a regular petrol or diesel car.

There are some very important differences, though. Obviously an electric motor doesn’t burn fossil fuel, instead using the electrical energy stored in the car’s battery to provide its propulsion. An electric motor is also much simpler: while a combustion engine has hundreds of moving parts all working in tandem with intricate timing, an electric motor has only one. This makes an electric motor much more reliable and much easier to repair.

Another key difference in the number of motors that a car might use. While pretty much all production ICE (Internal Combustion Engine) cars just have one engine, it’s not unusual for an electric car to have more than one motor. Yes, single-motor electric cars are also common, examples being the Nissan Leaf, Renault Zoe and lower-powered Tesla models, but higher-powered Teslas, along with alternatives such as the Jaguar I-Pace and Porsche Taycan, have two motors – one on the front axle and one on the rear – which give the car four-wheel drive.

Watch Porsche Taycan review 

Electric motors also deliver their power in a very different way to a combustion engine. While a combustion engine will have to be spinning at several thousand revs before it can deliver its maximum power and torque, an electric motor will deliver maximum force the very moment it starts spinning, meaning strong acceleration the instant you press the pedal. One of the main benefits of an electric car is this instant acceleration when driving.

Electric car batteries

This is, hands down, the most important bit of any electric car. This is what determines how far your car will go on a charge, how long it’ll take to charge, how long it’ll last and pretty much any other important factor you could mention. As such, an electric vehicle’s battery pack where the vast majority of the investment is made, in terms of time, money, research and development. It’s also the reason why electric cars are generally more expensive than petrol or diesel cars, and it’s by far the most expensive part to repair or replace if it goes wrong.

The batteries you find in electric cars are generally lithium-ion batteries, the same as you find in mobile phones or laptops, but much bigger. Lithium-ion batteries are used because they have a better power-to-weight ratio than other types of battery. That said, the battery pack is still a very heavy part of the car, relatively speaking, so it’s often placed as low down in the car as possible, usually in the floor. This helps the car’s handling, making it more stable when changing direction.

You charge the battery by plugging the car in. Most electric car owners do this at home, so some form of off-street parking is usually needed, and this can be done through either a three-pin domestic plug into a standard electrical socket (which is very slow) or a wallbox charger that either comes with the car or is subsidised by a Government grant.

If you have the means to charge at your place of work, this could also mean a significant top-up on your daily range. If neither of those solutions is available to you, you’ll have to rely on the public charging network and this infrastructure is getting bigger all the time.

This can have its problems though: nearby charging stations may be occupied, out of order, or not have the right connectors (sockets) for your kind of car. Charging stations are also run by a wide variety of different subscription companies, and it’s unlikely you’ll be signed up to them all.

Many electric cars are offered with a choice of battery. The higher the capacity of your battery, the further you’ll be able to drive on a single charge. Most electric cars will give you a range of at least 100 miles, while those with the longest range will take you way past the 300-mile mark.

Electric cars with the longest range

Bear in mind, though, that these are maximums, and the range you actually get on your journeys will depend on a number of factors: road conditions, traffic, how gently you drive and how many ancillary functions (headlights, windscreen wipers, air-con, radio, etc) you have running will all have an effect.

So too will the ambient temperature, and a surprisingly large effect at that. In warm weather, you can reasonably expect to get close to your car’s stated maximum range provided all the other factors are also on your side. In cold weather, though, a battery’s efficiency is greatly impaired, so you’ll find that the range you get plummets.

In normal circumstances, if your car’s maximum range is quoted at, say, 200 miles, you should reckon on getting about 160 miles. In very cold weather, we wouldn’t bank on doing much more than 100.

What happens when you drive an electric car until its battery dies? Watch our video below.

The maximum range your car gets will inevitably diminish over time, too. That’s because as batteries get charged up and run down again and again over time, they gradually lose capacity. You can limit how fast this happens by not fully charging or fully depleting your battery as often as possible. Keep your level of charge between 20% and 80%, and your batteries will last much longer.

How long to charge an electric car

Since your batteries are by far the most expensive part of your electric car, you might worry that it’s constantly losing capacity, and that’s understandable. However, the manufacturers of electric cars provide warranties to protect against this. These are separate to the warranty that applies to the rest of the car, as these are usually standard across a manufacturer’s entire range.

For example, buy a Renault Zoe, and most of your car is covered – like any other Renault – for five years or 100,000 miles, whichever elapses first. However, your Zoe’s battery is covered for eight years or 100,000 miles. If within that time its capacity drops to below 66% of what it was originally, it’ll be replaced free of charge.

If your battery pack needs replacing after the warranty period has expired, though, the cost of replacing it will fall on you, and that cost will be a very hefty one.

Are electric cars automatic?

Technically, no. Driving an electric vehicle does feel much like driving an automatic, in that you simply put the car into ?Drive’ and you speed it up and slow it down with the accelerator and brake pedals respectively, without having to change gears for yourself.

However, while an automatic car achieves this by switching the gears for you, an electric car achieves it by not switching gears at all. It simply doesn’t need to. That’s why, like in the Kia eNiro below, you only have to select D for Drive and off you go.

The reason is that most combustion engines can only spin up to a maximum of between 5000 or 7000rpm before they hit their rev limiter. What’s more, they can only develop their maximum performance in a very narrow band within that, maybe between 3000 and 4,500rpm, for example.

Electric motors, meanwhile, can spin much faster – 20,000rpm is pretty commonplace – and the level of usable performance they produce is pretty much the same strength no matter how fast they’re spinning. All this means that electric motors don’t need multiple gears to make them driveable, they can get away with just one. However, that gear does need to be chosen carefully to give a decent ratio between acceleration and top speed.

Are electric cars reliable?

In theory, electric cars should be more reliable than combustion-engined cars because they have far fewer moving parts, meaning that there’s less to go wrong.

But, that doesn’t mean that they last longer than conventional cars; in fact, the opposite is often true. That’s because the most important part of an electric car – the battery – naturally loses its capacity over time, meaning it can’t hold as much charge, therefore reducing the range of your car.

How long do electric car batteries last?

Exactly how long a battery lasts is something of an unknown and will depend greatly on charging patterns, but to get a rough idea of what you can expect from your battery, look at the battery warranties offered by manufacturers. These usually range between six and ten years, with around eight years being the norm.

Should I buy a used electric car?

Replacing the battery in an electric car is enormously expensive, and could easily cost more than the value of the car. As such, if you’re buying used, you need to make sure that the battery is in good shape. When fully charged, check that the car’s indicated range is reasonably close (maybe within 80%) to the car’s original maximum.

Compare electric cars side by side

If you can, we’d definitely recommend taking the time to find a car that’s still in its battery warranty, ideally with as much left on that warranty as possible. Another option is to hunt for a car that was originally sold on a battery leasing arrangement (Renault offered this option for a few years on its ZE models, although this has now been discontinued on new Renault electric cars).

This was originally designed to lower the purchase price of the car, making it more appealing, and to safeguard owners against the cost of battery replacement. The battery leasing arrangement means that once your battery gets below 75% of its original capacity (this threshold is specific to leased batteries, the cut-off is 66% in the case of an owned battery warranty), it is replaced free of charge. Think of it as insurance against getting clobbered by the enormous one-off cost of replacing the battery. Bear in mind that leasing the battery will mean you have to pay a monthly charge of around £50 or so, which will greatly increase your running costs. This could be enough to make the cost of running a used electric car disproportionately high.

Do electric cars have:

Most electric cars have a single gear that’s chosen to give a decent ratio between acceleration and top speed. However, they have no need for multiple gears like combustion-engined cars do.

No. The electric motor is the bit that provides drive in an electric car, effectively replacing the engine in a conventional car.

Some do, although instead of keeping the engine cool like they would in a petrol or diesel car, electric cars use them to keep other things cool, such as their batteries. The electric motor in an electric car doesn’t generate enough heat to need a radiator.

Catalytic convertors
No. A catalytic converter reduces harmful pollutants in exhaust gases, but because an electric car doesn’t give off any exhaust gases in the first place, it has no need for one.

No. While a combustion engine needs oil to remove pollutants and lubricate all the various moving parts, an electric motor has only one moving part, and the grease that lubricates it doesn’t get contaminated.

No. Exhausts are for removing waste gas from a combustion engine, and since an electric motor doesn’t give off any gas, exhausts aren’t needed. This is one of the main benefits of driving an electric car.

Yes. Although electric cars don’t have an engine to make them go, they still need to slow down and stop.

Yes. Electric motors produce virtually no heat, while combustion engines produce lots, more than enough to heat the cabin. So, an electric car’s cabin is heated by an independent heater.

See all electric cars 

Find out more:
Electric car charging guide
How much does it cost to charge an electric car
Find your nearest electric car charging point in the UK