How Do Electric Car Chargers Work?

Charging an electric car can seem almost miraculous – you just plug it in, wait, and then hit the road. But have you ever wondered how electric car chargers actually work?

The truth is, it’s not as simple as it seems.

That’s why Eco Happy has created this comprehensive guide to tell you everything you need to know about how electric vehicle (EV) chargers work. We’re going to tell you about the different components of an EV charger, what occurs during the charging process, the role of the different charging standards, and the different types of EV chargers that are currently available.

Plus, we’ll get you up to speed on EV charger installation, public charging networks, the environmental benefits of EV charging, and a whole lot more.

What Are Electric Car Chargers?

Electric car chargers, also known as electric car charging stations or Electric Vehicle Supply Equipment (EVSE), are devices specifically designed to charge an electric car. There are two main types of electric car charging stations: DC charging stations and AC charging stations.

By communicating with the EV, the charging station regulates the flow of electricity and manages the entire charging process.

Some EV charging stations take hours to recharge a battery while others can add a large amount of power within just a few minutes.

Electric car charging points can be installed in your home and there is also a network of chargers in public spaces around the UK. However, the number of public chargers you have close access to depends on your location.

How Electric Car Chargers Work

Ok, so you now know what an electric car charger is – but how do they work, and are all electric car chargers the same? Let’s take a look at exactly how these chargers work and how they differ from each other.

Components of electric car chargers

Charging cable

An EV charging cable is an essential component for all types of electric car chargers. It’s made up of three parts:

1. A length of wire
2. A connector that plugs into electric vehicles
3. A connector that plugs into a power source

The cable safely delivers power from the power source to the battery of the electric car. Different types of cables with varying power ratings are available so that you can effectively charge your car depending on its specific requirements.

A Type 1 charger is used for slower charging stations with power ratings between 0.37 kW and 7 kW. Type 2 chargers are used for faster charging stations with power ratings of 3.7 kW, 7 kW, and 22 kW. Type 2 chargers are the standard chargers for Asian and European electric vehicles.

For home charging, it’s important to consider the length of the cable you purchase. You can also choose between flat and coiled designs.

Connectors

The connectors act as the interface between the vehicle’s inlet port and the EV charging point. There are several different types of connectors, including:

• SAE J1772 (Type 1): This has a maximum output power of 19.2 kW and supports single-phase AC charging for Level 1 and 2 EV chargers.
• Mennekes (Type 2): Primarily used in Europe, this connector supports both single-phase and three-phase AC charging. Its maximum output power is 22 kW and it’s used for Level 2 chargers.
• CCS (Combined Charging System): This combines the J1772 connector with two high-speed DC charging pins. It supports single-phase and three-phase AC charging for Level 2 chargers and has a maximum output power of 22 kW.
• CHAdeMO: This connector has a maximum output of 50 kW and is used for rapid DC charging.
• Tesla Supercharger: This is only compatible with Tesla’s rapid chargers. Tesla Superchargers are very powerful and have a maximum output of between 72 kW and 250 kW.

When EV charging, the type of connector you need depends on the type of charging station and your vehicle’s inlet port. It’s crucial that you understand the different types of connectors so that you can charge your vehicle properly and safely.

Control unit

The control unit communicates with electric cars to regulate the flow of electricity to the battery and to ensure the charging process is efficient and safe.

It has several control and protection functions, such as:

• Continuous verification of the integrity of the protective conductor
• Verifying the correct connection of the vehicle
• Managing the charging period of the vehicle to optimise electricity consumption

Some control units also have a communication controller that gives feedback to the vehicle’s control system and passes on the required values to the power electronics.

User interface

The user interface, as the name suggests, is the part of the charger that the user interacts with. It’s designed to simplify the charging process and provide an intuitive user experience.

EV charging station interfaces usually feature bold typography, touchscreen displays, and colour schemes that make it easy to navigate the various options and enhance visibility.

Many chargers also allow EV drivers to download companion mobile apps that provide session histories, charging statuses, and map views for public charging stations.

Public charger interfaces should have convenient payment options and clear instructions on how to use them. They may also include troubleshooting workflows, diagnostic information, and live support to assist users and provide a satisfying experience.

LED indicators are often used for charging speed indications, to signify charging status, and for cable management guidance.

The charging process

Now, we’re going to break down how all of these components work together to charge electric cars.

Step 1

Using a charger that matches your car’s inlet port, attach one end of the charging cable to the charging station and one end to your vehicle. Your car and the charging station communicate with each other once the connection is established.

Step 2

Information about the car and charger’s limitations and capabilities are exchanged between the two. This includes things like maximum power and battery level.

If you’re using a public charger, the charging session is authorised once your car has been authenticated with a charging network app or card.

Step 3

The charger passes either AC or DC electricity to the car, depending on the type of charger. If it’s AC electricity, the car’s onboard charger converts it into DC – the type of electricity needed to charge the battery.

Step 4

As the electric vehicle charges, voltage, current, and temperature are constantly monitored by the charger and the car. This is to prevent damage to the battery or the charger and to ensure safety.

If any issues are detected, the charging process will stop automatically.

Step 5

The onboard battery management system optimises battery health and longevity by regulating the charging process. To achieve this, the system usually slows down the charging process when full battery capacity has almost been reached.

Step 6

Once your car is at the desired power level, the EV charging session comes to an end. You can then disconnect the cable from the car and the EV charging station.

The role of charging standards

As mentioned, there are different types of charger connectors. There are also several different types of charging standards used for EV charging stations.

You’ll notice that some of the standards have the same names as the types of connectors we covered earlier. This is because these standards were named after the specific connectors that were associated with them in the early days of electric vehicle charging.

These are the different types of electric car charging standards:

• CHAdeMO: This standard is most common in Europe and Asia and is used for fast DC charging.
• Combined Charging System (CCS): This standard is used for both AC and DC charging. It’s common in both the US and Europe and is supported by major network operators.
• ISO 15118: This standard is used internationally to enable “Plug & Charge” capabilities for electric vehicles. It allows electric cars and chargers to communicate seamlessly and securely to authenticate and authorise the charging process.
• Open Charge Point Interface (OCPI): This enables EV charging point operators to exchange information about charge points. It’s used for many things like tariffs, roaming, reservations, handling registrations, and authorising charging sessions.

The reasons these standards are so important include:

• Interoperability: They make sure that public EV chargers are compatible with a broad range of electric cars so that different types of vehicles can use the same chargers.
• Communication and data exchange: They allow EV charging point operators to communicate and exchange crucial information securely and efficiently. This may include information like user credentials, billing details, and technical directives.
• Safety: These standards help to ensure the safety of the vehicle, charger, EV drivers, and passengers. They also protect the user’s data from potential cyber threats.
• Seamless transactions: They make it easy for drivers to pay for their EV charging sessions at public stations.

Types of electric car chargers

Level 1 chargers

Level 1 chargers, also known as slow chargers, are the slowest type of electric car chargers. They’re AC chargers which are only found in home charging stations and are plugged into a standard 120-volt household outlet.

They usually have a maximum power output of 1 kW to 1.8 kW and take around 11 to 20 hours to fully charge an electric car from empty.

Due to this, many electric car owners with home charging stations choose to charge their vehicles overnight.

Level 2 chargers

Like Level 1 chargers, Level 2 chargers are also AC chargers. However, they’re faster and can charge an electric car from empty in around 3 to 8 hours.

The power outputs of Level 2 chargers range from 3 kW to 22 kW, and although they’re also commonly used for home charging, they require a 240-volt power source.

Level 2 chargers can also be found in workplaces and other public spaces.

DC fast chargers

DC fast chargers, or Level 3 chargers, can charge an electric car to 80% battery capacity from empty in about 20 to 30 minutes. The power output for these chargers ranges from 50 kW to 350 kW, and some of the newer chargers can even go as high as 400 kW.

It’s not currently feasible to install a DC fast charger in your home, which is why you’ll only find them at public charging stations.

Electric Vehicle Charger Installation

In the UK, it’s usually cheaper to charge an electric car at home than to use a public charger. On average, it costs around 48p per kWh to use a public EV charging station, while it costs around 32p per kWh to use a home charger.

Additionally, charging at home allows you to take advantage of cheaper, off-peak tariffs which can save you even more money.

But if you do decide to buy a home charger, what does the installation process involve? Let’s take a look.

Home EV charging station installation process

• Step 1: Your property is assessed to determine the best location for the charger and electrical requirements.
• Step 2: Any necessary electrical work is carried out. This can include placing and connecting the charger, routing wires from the electrical panel to the charger’s location, and ensuring the charger’s power supply can be supported by the electrical system.
• Step 3: Once the charger has been installed, the installer performs the required electrical testing and gives you a demonstration of how your EV charging point works. They may also show you how to use the accompanying mobile app.

Home EV charging point costs, incentives, and requirements

The costs of electric car charger installation can vary greatly but it’s generally around £800 to £1,200. However, homeowners in the UK may be eligible for a £350 grant from the Office for Zero Emission Vehicles (OZEV) to help offset some of the costs of installation.

If you decide to have an EV charging point installed, you’ll need to have off-street parking at your home, as this is a common requirement.

Public Charging Networks And Services

As electric vehicles become more and more popular in the UK, public charging networks are also continuing to expand. There are now several different providers of public EV charging points around the country that offer a variety of services.

The major players

The largest electric car charging networks in the UK are:

• BP Pulse (Chargemaster): With more than 8,000 EV charging points across the country, BP Pulse is one of the biggest networks in the UK. It has fast, rapid, and ultra-fast chargers, meaning its chargers’ power outputs range from 7 kW to 150 kW.
• Shell Recharge: This network has more than 8,600 EV charging points in the UK which include 50 kW rapid chargers and ultra-rapid chargers.
• Chargeplace Scotland: This network is funded by the Scottish Government and operated by SWARCO. It has more than 2,000 EV charging points in Scotland.
• Tesla Supercharger: The Tesla Supercharger network includes around 880 EV charging points across the UK. Its chargers have power outputs ranging between 120 kW and 150 kW.
• InstaVolt: This network consists of over 800 DC fast charging points in the UK. InstaVolt is also planning to add another 600 EV charging points to its network.

Subscription services

The costs of charging an electric car can mount up quickly, which is why it’s important to take advantage of the subscription services and membership benefits offered by EV charging networks in the UK.

Some network providers charge as much as 50p to £1 per kWh when users charge their electric vehicles. However, if you sign up for a subscription service with a network provider, you can receive discounted rates and sometimes even free charging sessions at specific locations.

For example, BP Pulse (Chargemaster) subscribers can charge their electric vehicles for 44p per kWh and gain access to free charging at a number of stations across the UK.

When you sign up, you get a month’s free subscription and £9 credit for the five following months. The subscription costs £7.85.

Even if you have a home electric car charger, it may still be worth signing up for a subscription to one of the major EV charging networks. This is due to the likelihood that you’ll still need to charge your electric vehicle when you’re out on the road.

However, if you have a home charger and only use your electric vehicle for short journeys, it probably isn’t worth it.

Roaming agreements

Roaming agreements allow drivers to charge their electric cars at the charging points of several different networks while only having an account with one network.

These agreements are designed to promote the use of electric vehicles in the UK and to make EV charging much more convenient for drivers.

Roaming network agreements are made up of three different layers:

• Layer 1: The charging network of a specific network provider like Shell Recharge.
• Layer 2: A more extensive local or public charging network.
• Layer 3: Hub and peer-to-peer roaming agreements made with other charging networks like BP Pulse.

Several networks in the UK offer these roaming services, including BP Pulse, Shell Recharge, InstaVolt, and IONITY. This means that EV drivers can use a single radio frequency identification (RFID) card or app to charge their electric cars at stations operated by different networks.

It’s hoped that access to seamless charging will encourage continued growth in the adoption of electric cars within the UK.

Challenges And Future Developments Of Electric Car Charging

As the use of electric vehicles continues to grow, there are plenty of challenges that will need to be addressed to facilitate the shift away from combustion engines.

This will require the need for rapid technological developments to ensure the charging of electric vehicles doesn’t become inconvenient.

Let’s take a deep dive into these challenges and the emerging technologies necessary to match the pace of change.

Charging infrastructure challenges

Range anxiety

Range anxiety is the fear that an electric car won’t have enough battery power to reach its destination, and that there won’t be an accessible charging point on the route.

While this is becoming less of a concern for certain areas in the UK, it’s still present in many regions due to a lack of public charging points.

This issue is particularly acute in the UK as around a third of the country’s households don’t have a driveway, meaning home chargers can’t be installed. Clearly, there is a huge need for adequate public charging infrastructure if electric vehicles are to be adopted as widely as hoped.

Grid capacity

Of course, as the number of charging points in the UK increases, so will the strain on the national grid. This will require a strategic deployment of charging points and additional grid reinforcement.

Currently, solar power and battery storage are two solutions being considered to support local-level charging. Technologies like this should also reduce the need to reinforce the grid extensively.

Finding the right mix of charging points

To support EV drivers without off-street parking and those making long-distance journeys, the right balance of rapid DC charging stations and on-street units needs to be found.

Reliability

To encourage the use of electric cars, stations must be able to deliver adequate power at peak times and downtime needs to be minimised. The aim is for the charging experience to be seamless for EV drivers.

Emerging technologies

Wireless charging

One of the most exciting developments in electric vehicle charging is the emergence of wireless charging technology. This enables electric vehicles to be charged when parked over wireless charging pads.

By eliminating the need for a cable and a physical connection between the car and the charger, the accessibility and convenience of charging are greatly increased.

Ultra-fast charging

Ultra-fast charging stations are already relatively common in the UK, as they allow EV drivers to add hundreds of miles of range to their batteries in minutes.

As these stations continue to be rolled out, they’re certain to alleviate range anxiety and make long-distance journeys in electric vehicles much easier.

Vehicle-to-grid (V2G) integration

V2G technology, or bidirectional charging, means that an electric car can discharge energy back into the grid. Essentially, it means that EVs can become mobile energy storage units which can assist in stabilising the grid by putting energy back into it during peak times.

Environmental And Economic Impacts Of Electric Vehicle Charging

The move towards electric vehicles is mostly driven by the need to find a more environmentally friendly alternative to combustion engine vehicles. But what are some of the environmental benefits of EVs? Plus, are there any economic benefits too? Let’s explore both of these questions.

Energy consumption and efficiency

EVs are far more energy-efficient than combustion engine vehicles. Around 59% to 62% of the energy they use from the grid when charging is converted into power at the wheels. On the other hand, only around 17% to 21% of energy stored in petrol is converted into power at the wheels.

In terms of efficiency, rapid DC charging is the best form of EV charging, with many studies indicating it is over 90% efficient. Studies also show that Level 2 charging is around 89% efficient, while Level 1 charging is about 83%.

If rapid and ultra-fast charging stations continue to be prioritised in the UK, energy consumption should continue to decrease while efficiency rises.

Reduced greenhouse gas emissions

The greatest environmental benefit of EVs is that they don’t produce any tailpipe emissions. Additionally, the power used to charge them can be generated from renewable sources like wind, solar, and geothermal, which further reduces the EV industry’s greenhouse gas emissions.

In fact, studies have shown that EV charging emissions can be reduced by 53% if the charging process is powered by renewable sources.

Economic benefits and job creation

It’s estimated that the expansion of the UK’s EV charging infrastructure will require between £8 billion and £18 billion in investments over the next 10 years. This level of investment is certain to create opportunities for companies in different sectors which will stimulate economic growth and job creation.

As more and more charging points are required across the country, there is likely to be a boom in employment opportunities within the construction, manufacturing, and technology sectors.

Clearly, the widescale adoption of EVs won’t just be good for the environment but will also have a positive impact on the UK’s economy and job market.

Electric Vehicle Charging Safety Tips

Both EVs and chargers are designed to be incredibly safe and it’s unlikely you will experience any safety issues when charging your electric vehicle. Still, there are a few tips you should follow to charge your vehicle efficiently and securely.

• Follow the guidelines: Always read the manufacturer’s guidelines in full before charging your vehicle for the first time. If you’re unsure about any of the information in the manual, contact your local dealer for clarification.
• Use certified equipment: The charging point you use should be certified by a nationally recognised testing lab like Intertek Milton Keynes or 3C Test Limited.
• Don’t use damaged chargers: If you notice visible damage to your home charger or a public charger, do not use it. There is a high risk of causing damage to your vehicle if you do.
• Proper installation: Home EV chargers must be installed by a qualified electrician. Usually, the provider will offer to install the charger for you using one of their qualified electricians.
• Residual current devices: A qualified electrician should install a residual current device as standard along with your home charger. This is vital for turning off the power if a fault is detected which can help to prevent fires.
• Don’t use multi-socket extension leads: When charging your EV at home, avoid using multi-socket extension leads. They’re not designed to handle the high power of an EV charger and using one can lead to fire risks.
• Regular inspection: Make sure you check your charging cable frequently for signs of wear and tear. If you notice any damage, don’t use it and replace it as soon as possible.

How Does EV Charging Affect Battery Health And Degradation?

• Frequent rapid DC charging: Frequently charging your electric vehicle with a rapid charger can accelerate battery degradation. This is because it puts stress on the complex electrochemical system of the battery. It’s recommended that you only use rapid chargers occasionally.
• Charging to full capacity: Each charge cycle wears an EV’s battery down slightly, which means it’s not ideal to charge your vehicle’s battery to its full capacity every time. Keeping it within the 20% to 80% range could potentially increase the battery’s lifespan by a few years.
• Slower charging methods: Regularly using slower AC charging can reduce the stress on your EV’s battery and reduce degradation. This is one of the reasons you should have a home charger installed if possible.

FAQs

How does cold weather affect EV charging?

Cold weather can affect EV charging in a number of ways, including:

• Slower charging: The ideal charging temperature for EVs is between 20 to 40 degrees Celsius. In lower temperatures, the battery needs to use energy to heat itself which can lead to a slower charging process.
• Reduced range: Low temperatures impact battery efficiency and can reduce the range of an EV by as much as 20%.
• Battery management: Some pre-conditioning features that allow EV drivers to warm up the battery when driving might not function properly in cold weather, leading to reduced efficiency.

What are the safety features of EV chargers?

Aside from the residual current device, there are other EV charger safety features, such as:

• Overcurrent protection: This prevents excessive current flow from EV charging stations which helps to prevent overheating and fires.
• Emergency shut-off switches: Charge points are fitted with emergency shut-off switches that stop the flow of energy during emergencies.
• Weatherproof design: Charging stations are designed to withstand weather conditions like snow, rain, wind, and hail.

Which charging networks can I use if I travel to Europe?

If you’re travelling from the UK to Europe in your EV, the best network to use is Plugsurfing. It gives you access to more than 200,000 charge points across the continent and the card or key costs just €9.95 (£8.50).

Depending on the country/countries you’re travelling to, there may also be various local networks you can use. Before travelling, research the specific networks, cards, and apps that are available in the countries you’ll be visiting. This allows you to plan ahead and avoid stressful charging situations during your travels.

Final Thoughts

As you can see, chargers for electric cars come in various forms, operate on different principles, and have an array of different charging speeds.

Understanding how they work, the factors that influence charging efficiency, and the environmental benefits of EV charging can help you to make more informed decisions about your own charging habits.

EV chargers aren’t just tools for refuelling vehicles; they’re key players in a transition to a greener and more sustainable future. As the UK’s EV charging infrastructure continues to expand, there will be huge benefits for the environment, the economy, and the job market.

If there’s anything more you would like to know about electric car chargers, feel free to contact Eco Happy.