It’s one of the first questions people ask: How long does it take to charge an electric car?
The answer is: it depends…
But that’s a wishy-washy answer. Come on, we can do this. We just need to apply a little Maths.
The workings below might appear a tad tricky. However, once you get the hang of it, you can then work out charge times in any scenario for any EV.
First, however, we give you example charging times for a typical electric car, the BMW i3, in various scenarios.
How long does it take to charge a typical electric car?
Let’s first provide a quick overview using a popular EV, the BMW i3.
The BMW i3 has a 42.2 kWh battery. Below we consider three common charging scenarios:
- Charging at home on a 7 kW charger
- Charging at work on a 22 kW charger
- Charging in public on a 50 kW charger
In all cases, we look at four different situations:
- The battery is completely empty (0%)
- The battery is one-quarter full (25%)
- The battery is half full (50%)
- The battery is three-quarters full (75%)
For charging at home and at work, the strategy is to get the battery back up to full, namely 100%. This is achievable on either a 7 kW or a 22 kW charger.
For charging in public at a 50 kW rapid charger, you can get up to 80% full fairly quickly. But, because of the limitations of battery chemistry when charged at a high rate, to go from 80% to 100% full takes ages. We therefore look at charging times up to 80% (not 100%) for public chargers.
HOME charging times for a typical electric car, a BMW i3 with a 42.2 kWh battery
- From 0% to 100% on a 7 kW home charger: 6 hours 2 minutes
- From 25% to 100% on a 7 kW home charger: 4 hours 31 minutes
- From 50% to 100% on a 7 kW home charger: 3 hours 1 minute
- From 75% to 100% on a 7 kW home charger: 1 hour 30 minutes
WORK charging times for a typical electric car, a BMW i3 with a 42.2 kWh battery
- From 0% to 100% on a 22 kW work charger: 1 hour 55 minutes
- From 25% to 100% on a 22 kW work charger: 1 hour 26 minutes
- From 50% to 100% on a 22 kW work charger: 58 minutes
- From 75% to 100% on a 22 kW work charger: 29 minutes
PUBLIC charging times for a typical electric car, a BMW i3 with a 42.2 kWh battery
- From 0% to 80% on a 50 kW public charger: 41 minutes
- From 25% to 80% on a 50 kW public charger: 28 minutes
- From 50% to 80% on a 50 kW public charger: 15 minutes
- From 75% to 80% on a 50 kW public charger: 3 minutes
Example: Kia e-Niro
So, how long does it take to charge an electric car?
We now want to show you how to calculate charging times in any situation. The best way to start is with an actual electric car model. Let’s choose the Kia e-Niro.
The e-Niro comes with a 64 kWh battery. We explain all about ‘kWh’ on our terminology page, but basically it means the battery holds 64 ‘units’ of electricity when fully charged.
Stop for lunch at a motorway service station
So you’ve been driving your e-Niro for a couple of hours and you’re getting hungry.
It’s 1pm and you pull in at a motorway service station for lunch.
Your battery is obviously not full at this point, as you have been driving for two hours. Let’s say instead of being fully charged at 100%, your battery is now down at 25%.
Here comes some maths. 25% of 64 kWh = 16 kWh. Your car has 16 kWh of electricity still stored in it.
Electric car charging station
You drive over to the EV charging area.
You plug your e-Niro in and go for lunch. But how long do you have for lunch?
The new e-Niro has a rapid charging socket. It’s a CCS type socket. Most CCS charging stations in the UK currently have a maximum charge rating of 50kW. We’ll use this 50kW figure in a minute.
Charge an electric car to 80%
There’s an odd feature of lithium-ion batteries – the ones you find in EVs – that an electric car battery can be charged up to 80% full quite quickly on a rapid charger, but then takes proportionally longer to get up to 100%.
So the trick at motorway service stations is to get your car back up to 80% charge and then drive off.
More maths. 80% of the e-Niro’s full battery is 51 kWh (80% of 64 kWh).
The tactic is therefore to charge from the current 16 kWh to 51 kWh while having lunch.
That’s an increase of 35 kWh (51 kWh minus 16 kWh).
EV time to charge
Let’s come back now to the rating of the CCS charge point, namely 50kW.
If you turn on a 50kW charger and leave it on for 1 hour, then 50 kWh of electricity will have flowed through it.
The maths is simple: 50kW multiplied by 1 hour = 50 kW hours, or 50 kWh.
Now, we only need 35 kWh of electricity to get up to our target 80% charge.
So, we don’t need to charge the electric car for a full hour – that would in theory give us 50 kWh which is too much.
How long do we charge for? If you divide 35 kWh by 50 kWh you get 0.7 or 70%. That’s the percentage of 1 hour we need to charge for. 70% of 1 hour (60 minutes) is 42 minutes.
If your question is: how long does it take to charge an electric car? The answer, in the example above, is:
If you pull into a service station in a 64 kWh e-Niro and are at 25% charge, it will take 42 minutes to get the battery back up to 80%.
That’s 42 minutes to go to the loo, have lunch, and check your email. Sorted.
Charging an EV at home
But maybe your question is: how long does it take to charge an electric car at home?
If you have an electric car charge point at home, it will probably be rated at roughly either 3 kW or 7 kW. We recommend the faster 7 kW rating – see our Charging Points page for further details.
Home chargers are much slower than motorway EV charging stations, but generally you have all night and the aim is to get to 100%.
Let’s assume you arrive home at the end of the day in your Kia e-Niro and are at 50% charge.
This time you want to go from 50% (32 kWh) to 100% (64 kWh). That’s a 32 kWh shortfall to make up.
Your 7 kW home charger in 1 hour can deliver 7 kWh of electricity (7 kW x 1 hour = 7 kWh). You need 32 kWh. So divide 32 kWh by 7 kWh per hour, and you get 4.57 hours.
So your e-Niro will be back up to 100% after 4 and a half hours of charging.
Leave it charging overnight to have that wonderful, smug “I always have a full tank in the morning” electric car feeling. Use a smart tariff to keep your bills as low as possible.
If you have solar panels, and you plug your car in when the sun is shining, you can charge your electric vehicle with free solar electricity. Solar panels won’t help charge your car any faster – the charging speed is limited by the rating of the charging point – but solar electricity does help to reduce your carbon footprint.
With both solar panels and battery storage, you can store surplus solar electricity produced during daylight hours and charge your car later in the day when electricity is cheaper.
To learn how to charge your EV more cheaply, read our dedicated page: How much does it cost to charge an electric car?
Miles per hour – It’s not what you think
We are all familiar with the concept of ‘miles per hour’ or mph. It’s how fast a car goes, right? Not necessarily.
In the electric vehicle world, mph refers to two different ideas:
- How fast the car goes, but also
- How many extra miles your electric car can go after 1 hour of charging.
This second meaning is very popular among EV drivers. In a nutshell, the questions is:
“If I plug my car into a CCS charging point at the motorway service station, and leave it for an hour, how many more miles will I then be able to drive?”
If 1 hour of charging at a rapid charge point gives you an extra 100 miles, then you could call it a 100 mph charger.
This new meaning of mph is both confusing and useful at the same time.
- It’s confusing because of the traditional usage of how fast your car goes.
- It’s useful because if you have 75 miles to complete your journey, and you know the rapid charger is 100 mph, then you can be confident of reaching your destination after an hour’s charge.
It’s not just the rating of the charging point that dictates how many miles’ range you can get inside your EV. Electric cars have their own charging rate limits. Here are the current fastest internal charging rates available:
- Audi e-tron 55 quattro > 150 kW
- Tesla Model 3 > 120 kW
- Tesla Model S > 120 kW
- Tesla Model X > 120 kW
- Jaguar I Pace > 100 kW
The four cars above are all hi-tech and pretty expensive. A ‘normal’ EV, such as the Nissan Leaf, will rapid charge at about 50 kW.
As we chart the growing success of electric cars, we will see charging times come down every year, as charging station ratings increase and battery technology improves.