News article

How does an Electric Vehicle (EV) charger actually work? 

EV charging with GRIDSERVE

Whenever you waft silently into a charging bay, plug in and then grab a coffee from Costa, do you ever think about what is going on behind those high frequency whines and massive fridge-like shapes? Well, let us tell you.

At GRIDSERVE, we’re proud of our small benevolent army of engineers that are making sure all the EV chargers at more than 190 locations are consistently full of electrons and working flawlessly, day and night. Whether you’re using an Electric Forecourt®, Electric Super Hub or Electric Retail Hub, we know speed, ease of use and availability of High Power EV chargers are the priority, so we’re doing everything we can to further expand this award-winning network.

When it comes to juicing up, we tend to have a double act performing all the hard work. Backstage is something called the power cabinet, an anonymous white box that is often hidden from view. Its job is to safely convert the high voltage, three-phase Alternating Current (AC) GRIDSERVE receives from the grid into Direct Current (DC) that can directly charge your car’s battery. All batteries runs on Direct Current, so you can think of your electric car and our EV chargers in a similar way to your mobile phone and its charger. Only much bigger.

Why does the grid use AC then, we hear you ask? Partly because AC can be transmitted across long distances without much energy loss, and partly because AC power can be stepped up or down in voltage with simple and low-cost transformers.

How an EV charger works

Power electronics covered, we move to the main event. The EV charger itself tends to be located at the end of the charging bay, surrounded by safety bollards, clothed in jazzy stickers and featuring a digital screen to display pricing, a contactless payment terminal and one or two EV charging connectors. In most cases, you’ll find the more popular CCS connector, although we continue to provide CHAdeMO connectors to ensure every electric vehicle on sale can use our network.

A figure expressed in ‘kW’ or kilowatts is writ large at the top of the charging totem and this describes the maximum power: the higher the kW figure, the faster the charge rate will be. Our latest High Power EV chargers are 360kW-capable, meaning they can add 100-miles of range in less than 10 minutes. Given such high rates of power, the charging cables feature liquid cooling to ensure they can efficiently deliver such a high amount of current to the vehicle. This explains why those cables can often feel quite heavy.

Despite that peak power output, it’s worth remembering that all electric vehicles are controlled by their in-car battery management systems. So, the maximum rate at which anybody can charge is always dictated by the vehicle, rather than the charger.

After removing the connector from its holster and plugging into the vehicle, the EV charger communicates with the vehicle’s battery management system and the GRIDSERVE data centre to facilitate the so-called ‘handshake’.

Every EV charger on our network is fitted with fibre optic comms and adheres to the Open Charge Point Protocol (OCPP) cloud platform, the internationally recognised standard for communicating in the EV charging industry.

From processing payments to recognising customer accounts, or even facilitating future services like auto charging, there are so many connected devices within this chain and they all need to be able to understand one another to avoid miscommunication.

Following a series of gateway checks, including protocols for contactless payment, the charge will start. In real time, the EV charger is then monitoring all communications, calculating how much electricity is needed, at what charging speed and at what cost.

This information is shared with the best-known EV charging apps – so all drivers know the real-time status of this charger – but the data is also analysed by GRIDSERVE Technologies to gather insight regarding this specific charger’s performance, which can then be benchmarked against the rest of the network. It’s this information that helps to foster a pathway for continuous improvement, which is how we keep improving the EV charging experience for all our customers.