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Over the recent years, electric vehicles (EVs) have surged in popularity the world over, with the UK aiming for a complete shift from ICE cars to electric ones.
The increase in their demand also increases the need for places to plug them in, aka EV charging points and stations.
Although the public EV charging infrastructure is growing at a substantial rate, most EV owners choose to plug their cars in their homes, since not only is it more convenient but, in many cases, also cheaper.
On the other hand, commercial EV chargers, such as the ones found in offices and other workplaces, offer an added benefit to the employees since they get a chance to charge their cars while they’re at work all day.
In order to install EV chargers on your commercial or domestic property, and to enjoy all of their benefits, you need to understand the different types of chargers and the ones most suitable for your needs.
With varying levels of charging speeds and certain criteria for installation, the 7kW and 22kW chargers are two of the most popular fast chargers available in the market.
Read on to find out what they do, how they are different from one another, how much they cost, and is it worth paying more for a 22kW EV charger:
Before we discuss the differences between 7kW and 22kW chargers, and which one would be more suitable for you, let’s look at the three broad categories of EV chargers: slow, fast, and rapid.
The difference is apparent in their names and the systems get gradually faster in terms of the time it takes to charge your electric car’s battery.
Slow chargers have power output between 2.3kW and 6kW, although the most common ones are rated at 3.6kW.
When charging on a three-pin plug, the electric car will typically draw around 2.3kW, while dedicated EV chargers will work at relatively higher charge outputs.
The charge times vary depending on the charging output and the EV being charged, with a 3kW unit taking around 6 to 12 hours for a full charge.
Slow charging is a popular option among EV owners who usually charge their cars in their homes overnight. They can also be found in workplaces and public points where people stop by for longer periods of time.
That being said, due to longer charging times, slow chargers are less common in public charging points and stations and tend to be older devices.
While slow charging can also be done via a three-pin socket, it is highly recommended that it be used merely as a backup option. For EV charging at home and in the workplace, a dedicated EV charger installed by a certified installer is the way to go.
Typically rated between 7kW and 22kW, fast chargers are at least twice as fast as slow chargers. Most dedicated EV chargers have this kind of output, with several homes in the UK also having an 11kW output.
Charging times vary depending on the vehicle and the charging unit, with a 7kW charger easily charging a 40kWh battery in around 4 to 6 hours, and a 22kW charger doing the same in 1 to 2 hours.
Fast chargers are usually found in workplaces or public charging stations such as car parks and supermarkets where you are likely to leave your car for a couple of hours.
You can also install a fast-charge wallbox charger in your home, provided that your house electrics can support it, such as in the case of 22kW three-phase EV chargers, which we will discuss more in a bit.
Rapid chargers are the fastest way to recharge your EV, with the most common AC ones rated at 43 kW and DC ones rated at 50 kW.
They are most commonly found at motorway services and in locations close to the main route where people usually need a quick recharge to be back on their way.
Depending on the EV model, rapid chargers can charge a battery to 80% capacity in just 20 minutes. Also, all rapid charger units have tethered cables and can only be used on EVs that are capable of rapid charging.
You might think that more power is better and that 22kW is the better option than 7kW since it is faster, but that might not always be true.
The charging power and speed best for you depends on several factors, such as the type of EV you own, the power supply your property receives, and of course, how important fast charging speed is to you.
That being said, if you think about it, 7kW isn’t all that slow either. It is a third of the total power going into a residential property and is capable of adding 20 to 25 miles of range to an EV.
If your EV is parked at your office throughout the day, a 7kW charger can add 150 miles of range to the car during the day. For people commuting below 10 miles, this is more than enough.
You also need to determine the number of EV chargers you require on your property since every building has a set amount of electrical power that they receive.
22kW chargers may use up all the available power and you will have only a few 22kW chargers that charge the electric cars unnecessarily quickly.
With relatively slower 7kW EV chargers, you can install more chargers that can be shared amongst several EV owners, and which will provide the required charging speed without putting any burden on the main power supply.
There are also a few criteria that need to be met in order to install 22kW EV chargers. Your property’s electricity supply must be three-phased and your EV must be capable of charging at that speed.
Since most homes in the UK have a single-phase power supply that provides up to 7kW to charge up an EV, most EVs charged at home are done at 7kW.
Also, since most EVs are not compatible with 22kW three-phase charging and do not have the required charging cables, they will charge no faster than 7kW, even while using a 22kW charger.
When discussing the differences between 7kW and 22kW EV charging, it is important to talk about the difference between single-phase and three-phase power supplies.
Alternating current (AC) power supply can be classified into single-phase and three-phase. Both allow EV owners to charge their cars through single and three-phase power outlets, respectively.
The difference between them is that in the former, the power flows through a single conductor, whereas in the latter, it flows through three conductors. As compared to single-phase charging, three-phase charging has a higher power transfer capacity of 22kW.
22kW EV charging refers to the rate at which the electricity transfers from the EV charger into the EV. It is thrice as fast as 7kW charging and can only be supported by properties that have a three-phase incoming power supply.
Since most homes in the UK have a single-phase power supply that provides up to 7kW to charge up an EV, most EVs charged at home are done at 7kW, making 22kW EV charging a rarity in homes.
A three-phase power supply is more commonly found in commercial settings such as offices, shops, factories, restaurants, and shopping centres; therefore, 22kW charging is more often seen in workplace office chargers and public car parks.
To check if you have a three-phase power supply in your property, you may contact your electricity provider and ask them. If not, you can also have your current system upgraded to three-phase.
Keep in mind, though, that it may be expensive to upgrade your power supply from single-phase to three-phase, with the cost ranging between £3,000 and £15,000, depending on your local electricity infrastructure.
The average time it takes to charge an EV depends on 4 factors:
When talking about fast chargers, a 22kW three-phase charger can charge three times faster than a single-phase 7kW charger.
Also, the capacity and health of the battery and the power of the charger play a crucial role here. The bigger the size of the battery and the slower the charging output, the longer it will take to charge it from empty to full.
To get a better idea of the relation, an electric car with a 100kW battery will take around 27 hours to charge with a 3kW charging point, around 11.5 hours with a 7kW charging point, and around 4.5 hours with a 22kW charging point.
When compared to a 7kW standard EV charger installation, the cost of fitting a 22kW charger is usually higher since it involves more material and labour.
You will need more material and bigger cabling for a 22kW installation, and while the accurate costs depend on the amount of electrical work involved, it would naturally take more resources to connect and test everything.
The additional amount depends on the specific job but you can expect to pay an additional £700 to £900 on top of the installation.
For home EV charger installation, you can receive a grant of up to 75% of the EV charger’s cost under the Government’s Electric Vehicle Homecharge Scheme (EVHS), with a cap set at £350 per installation.
To benefit from the grant, you must:
In order to support businesses with the upfront costs of installing commercial EV chargers, the Office for Zero-Emission Vehicles (OZEV) offers a Workplace Charging Scheme (WCS) that can also be used to reduce the costs by up to 75%.
The grant can be used to claim up to 20 single or 10 double charging stations. However, to be eligible for funding your business must:
For 22kW EV charging to be worth it, you need to have an EV that can actually charge at that much power and the required three-phase infrastructure on your property.
Since a majority of electric vehicles can only support up to 7kW and not many homes will be able to have a 22kW charger installed due to a single-phase power supply, a 22kW three-phase charger is not worth it for home installations.
Since most EV charging in homes takes place overnight, even if you have a three-phase power supply and a compatible electric car that could charge between 11kW to 22kW, it wouldn’t make a difference since it wouldn’t matter how fast or slow the charging took place.
However, if you have EVs that can charge at this rate and have a sufficient power supply on your property, you should definitely go for 22kW chargers.
22kW three-phase charging may also be useful if you have multiple electric cars. For instance, if you have a few EVs at home, having a faster charger option may offer you more convenience. A 22kW in this scenario would allow you to charge your cars faster, making it easier to share a single charger.
Also, it is now becoming more common for new domestic builds, such as houses with 6 or more bedrooms, to have a three-phase power supply from the get-go, in which case, it could be a good option to consider getting 22kW fast charging.
Coming to commercial properties, a three-phase power supply is more common in places such as offices, shops, factories, restaurants, and shopping centres; therefore, it would be a good idea to install 22kW EV chargers in business settings and public car parks.
In the end, it all depends on what you need and which type of charger works best for you. You need to keep in mind the number of electric cars you have and how often you need to charge them.
Whichever type of EV charger you install on your property, make sure it’s the right one so that you can enjoy all of their benefits that include convenience, cost-savings, and playing your part in making the environment cleaner.
According to the UK’s building regulations, all new homes and non-residential properties, including properties such as offices and supermarkets, as well as renovated properties with more than 10 parking spaces, are required to install EV chargers from 2022.
Newer regulations also state that the charging equipment needs to be “smart” to be able to monitor the electricity consumption during charges and send the accumulated data to the OZEV (Office of Zero-Emission Vehicles).
Therefore, if you are an EV owner or are planning to buy one in the near future (which you will have to since the UK government is already working towards it and has declared a ban on the sale of new petrol and diesel cars by 2040), now is a good time to speak to a professional EV installer and look into the best options.
At Calder Electrical, we install EV chargers in line with the current regulations and can offer a government incentive to reduce the installation costs for both domestic and commercial properties.
There are various chargers currently in the market and it can be a little confusing to choose the best one for your needs.
We will take out the hassle and provide you with the most suitable and affordable option, ranging from the standard systems to the smart ones that are becoming increasingly popular.
We are authorised and registered OZEV installers and our charge points come with a 3-year warranty. We offer all kinds of different options to choose from, such as wall-mounted to freestanding pedestal units with different types of chargers and charging speeds.
Contact us here or call us on 0800 612 3001 for our expert opinion and professional services!
Photo by Ernest Ojeh on Unsplash
