How long does it take to charge an electric car?
If you’re thinking about buying an electric car, one question you’ll likely have is how long does it take to charge? Conventional petrol and diesel cars can be topped up with fuel in a matter of minutes, but because electricity is transferred to the vehicle very differently and at a slower rate, electric vehicles take longer to charge.
However, recent developments in rapid and fast-charging technology, as well as vehicle battery technology, mean that charging an electric vehicle is a lot quicker than some people may think. The latest rapid chargers can give up to a 50 per cent charge in 30 minutes.
There are many factors that make up the charging time of an electric vehicle, and below we will run through them all.
This is the most common way to charge an electric vehicle. The Government’s Go Ultra Low campaign estimates that 90 per cent of electric vehicles are charged at home. How quickly your car charges at home depends on two factors: the speed of charge, and how much charge you need.
An electric car battery is always listed in kWh (kilowatt-hour) – a measure of energy. Meanwhile, the charging power from a connector is listed in kW – a measure of power. A quick way to know how long it will take to charge your electric car is to use this formula:
kWh = kW x 1 hour
This means a 2kWh battery, for example, can discharge 2kW of power in an hour.
At home, the maximum draw of current from a three-pin, standard 13 amp socket is 3kW. It’s worth bearing in mind that not all home sockets can supply this. However, some manufacturers advise not using the mains sockets for regular charging, as the high amperage the process draws can cause overheating on the socket. Consult your electrician if you’re likely to regularly charge your electric vehicle from the mains sockets.
Using the above formula, it would mean that at 3kW charge, it would take 13.3 hours to fully charge the 40kWh battery in a Nissan Leaf.
This is why householders often install a faster home charging unit to speed up the process. Using the same metric, a 7kW home charging wallbox will charge the 40kWh Nissan Leaf battery in 5.7 hours. There are also larger, 22kW home charging units available.
A crucial point to understand with electric vehicles is that you will rarely need to fully charge one. Much like running out of fuel completely in a petrol or diesel car, electric vehicles will unlikely run out of electricity if they’re driven normally and sensibly. This is why a 60 or 80 per cent charge is often a more accurate representation of charging time.
In this instance – and using 3kW and 7kW home charging units respectively – a home charge will take 10.7 hours from 20 per cent to 100 per cent, and 4.6 hours.
Importantly, most electric vehicle owners will charge their car overnight when it’s not used. When viewed like this, you could say they are saving time over a conventional petrol or diesel car.
This is because when they come to use the vehicle in the morning, it’s ready to go. If driven within its range, it won’t require plugging in until the evening. Conversely, a petrol or diesel car might require refuelling. This is always done outside the home, and takes much longer than simply plugging a connector into a socket.
Public charging stations often work much quicker than the 3kW charging speeds at home. As of August 2018, there are over 17,500 public chargers in 6,093 locations, meaning finding one is easy.
Public charging stations can be divided into fast and rapid chargers. Fast chargers work anywhere between 7kW and 22kW, while rapid chargers work between 43kW and 50kW. Tesla’s Supercharger network works at 120kW, but this is solely reserved for Tesla owners.
There’s no difference between a home charging unit at 7kW or a public charging unit at 7kW, so using the same 40kWh Nissan Leaf, it would be fully recharged in 5.7 hours.
An 11kW public charger would fully recharge the car in 3.6 hours, while a 22kW unit would do so in less than two hours. A 50kW rapid charger would charge the Leaf in 48 minutes.
Often the idea with public charging stations is not to fully recharge an electric vehicle, but to give it enough juice to make the trip home or to the next stopover.
It’s worth bearing in mind that not all electric vehicles come with the capacity for rapid AC or DC charging. This means they are often limited to either 22kW or 7kW fast charging.
It’s also important to note which connector type your car has, as some charging stations do not support every connector type possible. Consult your vehicle brochure or handbook to find out the correct charging types and speeds for your current or potential electric vehicle purchase.