How long does it take to charge an electric car?
October 25, 2022 by carwow staff
Wondering how long an EV takes to charge? Wonder no more
Electric cars can take as little as 30 minutes or as long as 48 hours to charge up. That clearly indicates there are a fair few variables to consider when looking into how long EVs take to charge.
Here, we’ll look cover the ins and outs of EV charging times, and what you can do to get the quickest recharge possible while maintaining a healthy battery.
Electric car charging times
Before we get into the nitty gritty, it’s worth a quick overview of what determines how long an electric car takes to charge.
There are many, many different models of EV on sale today, and these are available with different size battery packs. In many cases car makers will sell you a larger battery pack as an upgrade for an individual car.
EV battery packs are measured in kiloWatt hours, or kWh. A kWh is a measure of energy. A small EV battery pack might be 30kWh. A large EV battery pack might be 100kWh.
How is charge time calculated?
Think of the size of the battery pack in the same way you would the size of a fuel tank in a petrol or diesel car.
Just as EVs have different size battery packs, EV chargers charge at different speeds. Think of this in the same way you would the rate at which petrol flows from the petrol pump (EVs can’t charge as quickly as this, but the principle is the same).
A three-pin domestic plug would charge at 2.3 kiloWatts (kW), whereas an ultra-rapid public chargepoint like the kind you might find at a motorway services could deliver a charge at 150kW.
Determining how long an EV would take to charge up is therefore a simple question of dividing the battery size by the speed of the charge.
For example, a 100kWh battery would take 40 minutes to go from full to empty using a 150kWh charger. If the charger you found only delivered electricity at 50kW, it would take two hours; and if all you had was a three-pin socket it would take a little under 43.5 hours (100 divided by 2.3 = 43.48).
Obviously if the electric car in question had a smaller battery, let’s say a 50kWh pack, it would take 20 minutes to go from full to empty on a 150kW charger, 60 minutes on a 50kW charger, and 21.74 hours using a three-pin socket.
EV charging in the real world
The above is based on the sort of maths you might do in an exercise book – a 100kWh battery takes an hour to charge on a 100kW charger – nice, neat, straightforward.
The real world has an annoying habit of having more shades of grey than an exercise book, though, while EV batteries are complex things. To help maintain their ‘health’ (IE their longevity and capacity), batteries have sophisticated management systems that can vary the rate of charge they receive. Other, external factors can also affect charging speed.
Below is a list of things that can impact how quickly the battery will be charged.
How full the battery is
The rate of charge will typically be slowed by the car as the battery gets closer to 100% charged; this tends to be particularly noticeable when using a rapid public charger.
The ambient/battery temperature
As sophisticated bits of kit, EV batteries don’t like very hot or very cold conditions, so the car can slow the rate of charge if these are detected.
Other people using the same EV charger
Many public EV chargers have two plugs coming out of the same unit. If two cars are plugged into the same unit, the charger may not be able to deliver optimum charge to both, so the speed of charging can be slowed. The same effect can be experienced if a lot of people are charging in the same area, or if electricity demand is particularly high in a region or power network.
Your car’s maximum rate of charge
Newer EVs tend to be able to receive a faster rate of charge than older ones, while some manufacturers will sell you an upgraded charging system that can receive electricity at a quicker rate. A car that is only rated to receive electricity at 50kW will charge no quicker than that even if it’s plugged into a 150kW charger (though it is perfectly safe to do this).
We should also highlight that a 0-100% charge is almost unheard of with electric cars. Drop down to 0% and you risk a) coming to a standstill on a public road and b) not doing the battery any good. Charging to 100%, meanwhile, is also not recommended in the interests of long-term battery health.
For this reason, charging to 20% to 80%, or 15% to 90%, is more typical, and it is these types of charging session that manufacturers often highlight in their marketing material.
Let’s say for the sake of simple maths that you were charging from 30% to 80% and had a 100kWh battery. That would require you taking 50kWh’s worth of electricity, which would take an hour to deliver from a 50kW charger, and 20 minutes from a 150kW charger.
Also bear in mind that a lot of EV owners have off-street parking and a home charger to go with their cars. These dedicated home chargers typically deliver electricity at a rate of 7kW, with owners plugging in every night, and often taking advantage of scheduled charging sessions based around off-peak electricity prices. Thus the question ‘how long does it take to charge an EV?’ is often less crucial than it might first seem.
We’ve highlighted some typical charging times below based on what kind of charger you’re using, although this comes with a big caveat:
EV efficiency is really important
Just as petrol and diesel cars have different levels of efficiency (measured in miles per gallon, or mpg), some electric cars go much further on a single kWh of electricity than others.
A big, heavy inefficient EV might only do 2.5 miles for every kWh; an EV such as this would do 250 miles on a 100kWh battery pack, assuming it was used from full to empty.
A smaller, more efficient EV might do five miles per kWh, giving it an identical 250-mile range from a 50kWh battery pack, or a 500-mile range using the same 100kWh battery (though this is unlikely, as bigger batteries are much heavier than smaller ones, which leads to a heavier, less efficient car.)
It is for this reason that the times below are very much a rough guide; an efficient EV could take on a mile’s worth of charge at twice the speed of an efficient EV even though both were being charged at the same rate simply because it is able to go further on a single kWh.
Charging at home (approx. 10-to-30+ miles of range per hour)
To most effectively charge your car at home, it’s worth installing a dedicated charging point, commonly known as a wallbox.
Typically, charging at home using a dedicated wallbox gives you anywhere between 10 and 30 miles of extra range per hour, but this varies depending on your local grid, type of wallbox and the model of electric car you have. For example, Tesla offers a 22kW home charger which is said to give a Model 3 40 miles of range per hour of charge – though most homes are only capable of having a 7kW charger installed, unless you want to spend serious money getting three-phase power installed (this is a type of electricity feed typically used at industrial and commercial sites).
Generally speaking, a dedicated wallbox will have you covered if you want to charge your electric car overnight and have it fully charged by the morning.
It’s worth noting you will have to pay to have a wallbox installed; budget £1,000 or so for one of these, and be sure to get quotes and arrange installation well before your EV arrives, as lead times can be lengthy.
It’s possible to charge your car up through a conventional three-pin plug socket as well, but the speed of charge will be greatly reduced, while this is not recommended from a safety point of view, as you will be putting heavy, continuous demands on the socket.
If you’re interested in having a home EV charger installed, speak to Rightcharge, carwow’s official EV charging partner. Rightcharge is the easy way to get a home charger installed for your new electric vehicle. They will recommend the right charger, match you with a trusted installer and help you find the best energy deal in a few simple steps. And in a special offer for carwow customers, Rightcharge is offering 250 FREE miles in the form of public charging credit, redeemable when your charge point is installed.
Public charging points (approx. 20-to-80-mile range per hour)
Public electric car charging points are becoming more common by the day and can be found in a range of locations, including town centres, supermarkets, workplaces, service stations, just to name a few.
Some of the most common outputs for public charging points are 7kW outlets, similar to the type you can get installed at home. These typically will give your car 20 to 30 miles of range per hour, while some outlets are rated at 22kW.
Charging an electric car through a public charger is likely to cost you, though. There will be some freely available outlets, typically at supermarkets, but others may require you to subscribe to a particular provider or use a pay-as-you-go method.
You might even be able to charge up at your workplace. If there isn’t already a dedicated charger, ask your employer about looking to install one — there’s a government grant called the Workplace Charging Scheme which can help cover the costs for businesses installing chargers.
For charging networks that offer subscription services, you can usually use their dedicated smartphone app to check current availability of a charger (so you aren’t left stranded if you turn up at a charger only to find it’s in use), and see how much it will cost you.
If you want to see public charging points local to you, check out this handy EV charging stations map.
Rapid charging points (Full charge in around an hour)
If you find yourself running low on battery range halfway through a long drive, public fast-charging points are usually the quickest way to top up and are most commonly found in motorway service stations and public car parks. These chargers are usually rated at 50kWh (but can reach up to 150kW or more), so can charge most EVs from empty to 80% in less than an hour.
The speed of fast-charging technology will only increase over time, and will further ease any anxiety associated with charging an electric car. For example, if your vehicle supports it, its battery could be charged from flat to full in comfortably less than an hour.
It’s worth noting though that plug-in hybrid cars often do not support rapid charging.
Tesla Superchargers (Full charge in around 40 minutes)
Tesla is one of the biggest and most famous car brands of all time – despite being one of the youngest.
Part of that success has been the dedicated Tesla Supercharger network, which can provide a full charge to its latest models in around 40 minutes. Most of Tesla’s superchargers in the UK are rated at 150kW, but it is currently working on rolling out one megawatt cabinets in the future, so expect things to get even faster.
Sadly though, you can’t yet use any other electric vehicles on Tesla’s Supercharger network yet, although it’s possible Tesla will allow other manufacturers to use its Superchargers in the future.
Our handy Tesla charging stations map shows you where Tesla’s nearest charging point is to your location.
Get your next electric car with carwow
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Got more questions about electric cars? Take a look at these frequently asked questions:
How far can an electric car go?