How long it takes to charge an electric car
Going green is a wonderful reason to move to electric cars. However, all of us are highly pragmatic. How long does it take to charge an electric car in the UK? This is the question many people bear in their minds. And this is the question that worries them and make them hesitate whether to but a petrol car or an electric vehicle. Therefore, knowing the EV charging time is of great importance. For example, this enables an EV owner to plan the day and include his charging needs coverage in his schedule.
In this post, you will, at least, find the most accurate and detailed answer to this important question.
How to calculate EV charging time
To estimate the EV charging time, the following data are of great use:
- Car battery size,
- EV charger power (output capabilities),
- On-board charger power (input capabilities).
To make things easy to understand, we will illustrate the importance of these parameters with en example. So, let’s suppose you need to fill a bottle with water (kind of EV charging). What parameters and options do you have then?
- First, it is bottle volume (kind of EV battery size). To clarify, this determines how much water you need to pour into the bottle to make it full. For example, it can be 1 liter, 2 liters, etc.
- Second, it is the way you fill a bottle (kind of EV charger power). To clarify, this determines how much water (water flow speed) comes out of a vessel where you initially store it. In other words, this is water output capabilities.
- Third, it is bottleneck throughput (kind of on-board charger power). To clarify, this determines how much water can really come into a bottle during a specified period. For example, its diameter may be 1 inch, 10 inches, etc. In other words, this is water input capabilities.
Now, let’s assume the water flow speed and bottleneck throughput are constant. Given this, you need a certain amount of time to fill a 1-liter bottle and twice as much time to fill a 2-liter bottle.
Then, let’s assume the bottle volume to be constant but other factors vary. For example, you want to pour water from a bucket into a 1-inch neck bottle. Yes, it takes just a few seconds to pour all the water out of the bucket. However, as a bottleneck diameter is smaller than a bucket one, bottle input capabilities are less than bucket output capabilities. Thus, you need to thin a water stream to adjust output capabilities to input ones. Or you use a simple dropper to fill a bottle. In this case, it takes hours to fill the bottle but the size of its bottleneck throughput is not to blame for this. Such a long filling time is the result of slow and small output a dropper has.
The same is true when it comes to charging an electric car. However, filling an electric car battery is a bit more complicated as it has certain specific. First, to use DC fast charging stations, you need to have an on-board charger that can deal with DC. Second, many now popular electric cars have Lithium-ion batteries under their hoods. This battery type does not like complete discharge. Besides, charging speed is not the same during the whole cycle. That is to say, as soon as the battery is 80% filled, the speed gets slower.
Thus, to calculate the EV charging time in the first run, use the following algorithm:
- Find out your car battery size, on-board charger limits (maximum power your car can accept), and the charger power (maximum power that station provides).
- Compare your on-board charger limits and the station power. Choose the lowest of these two characteristics to use in your estimations. Divide your car battery size onto the figure you have got in the previous step and the time you require in your particular case.
However, the real-world practice shows that this algorithm works well for the first 80% state-of-the-charge. Filling the remaining 20% of the battery takes around additional 30% of the time.
How exactly long it takes to charge an electric car at different charging stations
Now, let’s get closer to the real numbers about the time you need to feed your EV. Generally, you have three options here– slow, fast, and rapid charging.
To provide you with detailed examples, we turn to battery electric cars that are popular in the UK.
Electric cars popular in the UK and their features
| Make, model | Battery capacity, kWh | Onboard charger power accepted (max), kW | |
|---|---|---|---|
| AC charge port | DC charge port | ||
| Volkswagen e-Golf | 35.8 | 7.2 | 40 |
| Nissan Leaf | 40.0 | 6.6 | 46 |
| BMW i3 | 42.2 | 11 | 49 |
| Renault Zoe | 54.7 | 22 | 46 |
| Tesla Model S | 100.0 | 16.5 | 200 |
Sources: gov.uk, ev-database
Slow charging
Slow charging refers to facilities that provide power of less than 7 kWh. Common options in the UK are:
- 3-pin facility of 2.3kWh,
- 3kWh stations,
- 4-5kWh stations.
Typically, electric vehicles have two cables for AC charging. The first cable is a type 2 cable to plug a car into a station. The second cable is a cable with a regular plug you can use to feed your car by just plugging it into your domestic wall socket.
We do not recommend you to use 3-pin charging as your everyday option. First, it is too slow even to the most patient persons and takes too much time to charge a car. Second, plugging the 3-pin cable, you create additional load on your home electrical networks that doesn’t make it good in the long run. Thus, the 3-pin cable is a good option when you have to stay in the place with no station installed but have an urgent need to top up the battery.
Slow charging indicators
| Make, model | Battery capacity, kWh | Charger power, kW | Real-world charging time |
|---|---|---|---|
| Volkswagen e-Golf | 35.8 | 2.3 | 16h30m |
| 3.7 | 10h15m | ||
| Nissan Leaf | 40.0 | 2.3 | 18h30m |
| 3.7 | 11h30m | ||
| BMW i3 | 42.2 | 2.3 | 19h30m |
| 3.7 | 12h15m | ||
| Renault Zoe | 54.7 | 2.3 | 26h45m |
| 3.7 | 16h45m | ||
| Tesla Model S | 100.0 | 2.3 | 48h45m |
| 3.7 | 30h15m |
Sources: ev-database
Fast charging
When it comes to EV solutions with a power output of 7-22 kWh, it is EV fast charging stations we talk about. Typically, 7kWh stations are widely used at home. The perfect solution is to feed your vehicle overnight. First, this is the time when you are sleeping and do not have any deals to ride out and about. Second, if you have an Economy 7 tariff, you can enjoy lower electricity prices. Thus, you can reduce your EV driving expenses.
EVSE you find in public places are usually 11 or 22 kWh, though 7 kWh public chargers are also not unheard about.
Fast charging indicators
| Charger power, kW | Power accepted, kW | Real-world charging time |
|---|---|---|
| Volkswagen e-Golf (35.8 kW) | ||
| 7/ 11 /22 | 7.2 | 5h15m |
| Nissan Leaf (40.0 kW) | ||
| 7 / 11 / 22 | 6.6 | 6h30m |
| BMW i3 (42.2 kW) | ||
| 7 | 7 | 6h15m |
| 11 / 22 | 11 kW | 4h15m |
| Renault Zoe (54.7 kW) | ||
| 7 | 7 | 8h30m |
| 11 | 11 | 5h45m |
| 22 | 22 | 3 hours |
| Tesla Model S (100.0 kW) | ||
| 7 | 7 | 15h15m |
| 11 | 11 | 10h15m |
| 22 | 16.5 kW | 7 hours |
Sources: ev-database
Fast charging stations are more favorable than slow ones. To clarify, even the slowest in the range cuts the charging time at least twice when compared to 3-pin charging. However, limited by their maximum energy input capabilities, not each car can take full advantage of more powerful solutions.
So, as BMW i3 can accept maximum 11 kWh, there is no difference in its charging time when using 11kWh or 22 kWh stations.
Close to similar, we have Tesla Model S on-board charger limits. Its top input power is just 16.5 KWh, it can’t take all advantages 22kWh station provides. So, it’s charging time is just 7 hours instead of 5.2 hours you can expect this EVSE can deliver.
Remarkably, the lowest charging time Nissan Leaf and Volkswagen e-Golf can have with AC charging are, respectively, 6h30m and 5h15m. To clarify, their top-up speed doesn’t increase as the station output increases as their input capabilities are limited to, respectively 6.6 kWh and 7.2 kWh.
Rapid charging
Rapid charging deals with direct current (DC) charging and, thus, great power. Therefore, such solutions are always public stations. They are the fastest solutions, specially designed and produced by their EV charging manufacturer to supply DC right into the car battery. Thus, the stations fill the battery from flat to 80% of its capacity just for half an hour. However, after 80% charge has been reached, the battery power input significantly lowers and the charging time greatly arises. Therefore, it is not rational to try filling the battery in full.
Generally, in the UK there are several types of rapid EVSE that differ with the power they supply. However, the most common ones supply 50 kWh power. Besides, there is a wide network of Tesla superchargers and a few other high-powered stations with a 120-150 kWh output. More powerful solutions of 175 kWh or are the rare thing because there are just few EV models that accept such a great output (but still, they exist, with Porsche Taycan Turbo S as an example).
In our most popular EV selection, all vehicles except Tesla, accept DC power of less than 50 kWh. Therefore, a 50 kWh EVSE is all the owners of these cars need to top up their battery in no time.
Rapid charging (50 kWh) indicators
| Make, model | Battery capacity, kWh | Power accepted (max), kW | Power accepted (avg), kW | Real-world charging time |
|---|---|---|---|---|
| Volkswagen e-Golf | 35.8 | 40 kW | 39 kW | 36 min |
| Nissan Leaf | 40.0 | 46 kW | 40 kW | 40 min |
| BMW i3 | 42.2 | 49 kW | 47 kW | 36 min |
| Renault Zoe | 54.7 | 46 kW | 41 kW | 56 min |
Sources: ev-database
As you can see, it takes 36-40 minutes to charge Volkswagen e-Golf, Nissan Leaf, and BMW i3. The owners of Renault Zoe have to spend almost an hour to fill their battery from flat to 80% due to the larger battery size given with the same input capability.
Tesla stays apart from them and enjoys superchargers and other high-powered stations.
Rapid charging indicators for Tesla model S with a 100.0 kWh battery
| Charger power, kW | Power accepted (max), kW | Power accepted (avg), kW | Real-world charging time |
|---|---|---|---|
| 150 kW | 150 kW | 95 kW | 65 min |
| 250 kW | 200 kW | 110 kW | 44 min |
Sources: ev-database
Instead of summary: charging speed in miles
To deep further, it is not extra Watts you are concern about. It is extra miles to ride you want to get. Here, we have estimated how many miles you get after having a half-an-hour session.
Miles added with slow, fast, and rapid solutions
| Make, model | Battery size, kWh | Station type | Station power, kW | Miles added |
|---|---|---|---|---|
| Volkswagen e-Golf | 35.8 | Slow | 2.3 / 3.7 | 3.5 /6 |
| Fast | 7 – 22 | 11.5 | ||
| Rapid | 50 | 70 | ||
| Nissan Leaf | 40.0 | Slow | 2.3 / 3.7 | 3.5 /6 |
| Fast | 7 – 22 | 10.5 | ||
| Rapid | 50 | 70 | ||
| BMW i3 | 42.2 | Slow | 2.3 / 3.7 | 3.5 /6 |
| Fast | 7 / 11 –22 | 11.5 / 17 | ||
| Rapid | 50 | 80 | ||
| Renault Zoe | 54.7 | Slow | 2.3 / 3.7 | 3.5 /6 |
| Fast | 7 /11 /22 | 11.5 / 17 / 33.5 | ||
| Rapid | 50 | 75 | ||
| Tesla Model S | 100.0 | Slow | 2.3 / 3.7 | 3.5 /6 |
| Fast | 7 /11 /22 | 11.5 / 17 / 23 | ||
| Rapid | 150 / 200 | 155 / 175 |
So, with slow charging the number of miles added per half an hour is so tiny that you can hardly ride from the Buckingham Palace to Tower Bridge, no matter what car you drive. Fast charging provides you with more long distance. For example, 11 kWh station gives you around 17 miles during just half an hour charging, so you can take two round trips on the route the Buckingham Palace –Tower Bridge. At last, after the rapid charging session of the same duration, you can ride from London to Birmingham if you are driving Tesla. Or at least to Cambridge if you are on Nissan Leaf or another similar car. Bon voyage and have a nice trip!