How long does it take to charge an electric car?
If you're going to buy an electric car, one of your main concerns will no doubt be how long it'll take to charge the battery. Petrol and diesel cars can be filled with fuel in just minutes, but the same can't be said of electricity when it comes to electric vehicles.
However, the latest advances in fast and rapid-charging technology mean that charging an electric car can take a lot less time than you may think. The most powerful rapid chargers – although not yet very common in the UK – have the ability to charge compatible electric cars in just minutes, making them a much more viable prospect for drivers who regularly travel long distances.
Studies have also shown that the vast majority of electric-car charging takes place at drivers' homes, instead of at purpose-built forecourts as is the case with internal-combustion-engined vehicles. So even if a full battery top-up takes several hours, it doesn't matter, because once a car is plugged in, it can be left to its own devices overnight.
The length of time it takes to charge an electric car depends on a number of different factors. Here, we lay out each of these factors and explain how charging works.
This is the most common way to charge an electric vehicle, with the Government’s 'Go Ultra Low' campaign estimating that 90% of electric cars are charged at home. How fast your car charges at home depends on two factors: the power supply and the quantity of electricity you need to charge your car's battery.
The size of an electric car battery is always measured in kWh (kilowatt-hours) – a unit of energy. Meanwhile, the charging power from a wallbox or any other charging source is listed in kW – a measure of power. A quick way to know how long it'll take to charge your electric car is to use the simple formula: total charging time = kWh ÷ kW
This means, for example, that the 35.5kWh battery in the Honda e city car will take five hours to charge fully when plugged into a 7kW supply. Standard three-pin domestic sockets draw anything up to a maximum of 3kW.
However, some car manufacturers advise against using mains sockets for regular charging, as the high amperage drawn over such a long period of time can cause overheating of the socket. We recommend consulting a qualified electrician if you’re likely to regularly charge your electric vehicle from a standard mains socket.
The above is why electric-car owners often install a faster wallbox charger to speed up the process at home. These typically supply up to 7kW of power – and sometimes more if the property has a three-phase electricity supply. Most UK homes are restricted to a single-phase supply, however, and upgrading is likely to cost thousands of pounds.
It's important to note that you're very unlikely to have to fully recharge you car's battery every day from zero to 100%. Much like running out of fuel completely in a petrol or diesel car, electric vehicles are very unlikely run out of electricity if they’re driven sensibly. This is why you're only ever likely to charge a battery up to 60 or 80% of its maximum capacity based on most people's average daily mileage.
Importantly, most electric-vehicle owners charge their car overnight when it’s not being used. When viewed like this, you could be saving time compared to driving a petrol or diesel vehicle, as you'll rarely have to go out of your way or make a dedicated trip to your local forecourt to fuel up. This is because an overnight-charged electric car is ready to go as soon as you need it. If driven within its range, it doesn't need to be plugged in until the evening. Visiting a petrol station takes much longer than simply plugging a connector into a socket.
Public charging stations often work much faster than the 3 or 7kW speeds available at home. As of late 2020, there are nearly 35,000 public chargers spread over 12,000 locations in the UK, meaning finding one is becoming increasingly easy.
Public charging stations can be divided into two categories: fast and rapid. Fast chargers work anywhere between 7kW and 50kW, while anything above that threshold can be considered a rapid charger. Tesla’s Supercharger network works at up to 120kW, with speeds of 250kW arriving next year. However, this network is reserved for Tesla owners. Meanwhile, IONITY is rolling out a network of 350kW chargers across Europe, theoretically capable of delivering top-up times "as low as eight minutes". At the time of writing, only a couple of electric cars are equipped to accept that maximum charging speed, however more will arrive in the next few years.
There’s no difference between a home charging unit at 7kW or a public charging unit at 7kW, so using the same 35.5kWh Nissan Leaf above, it would be fully recharged in a little over five hours. An 11kW public charger would fully recharge the car in just over three hours, while a 22kW unit would do so in less than two hours. A 100kW charger would replenish the battery from empty to 80% in just over a quarter of an hour.
When it comes to public charging stations, most people won't fully recharge an electric vehicle, but will top up just enough to make the trip home or to the next stopover. This is because rapid-chargers slow down after a battery becomes around 80% full, as it becomes more and more difficult to force electricity in at such a high rate. It’s worth bearing in mind that not all electric vehicles come with the capacity for rapid AC or DC charging. This means some will be limited to either 22kW or 7kW fast charging, so it's worth double checking this before you buy any particular model.
It’s also important to note which connector type your car has, as some charging stations don't 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.