In this post, I disclose the features that make a good electric vehicle (EV) charging device. I’ll dive a little deeper into the technology and finally will give you some pointers to consider when building EV charging networks.
I’m focusing more on charge points used in private charging services - basically AC chargers. However, we see also some small power DC units that are installed in these locations. Maybe more in the future.
This information is relevant to the providers of electric vehicle charging services to their customers (EV drivers). These providers are often called charge point operators and they can be energy companies, EV charging operators, hotels, supermarkets, facility management companies etc.
EV charger is the unit that is used to charge electric vehicles’ batteries. It has several names like charge point, EVSE, wall box, charging station, socket, connector etc. We divide EV chargers into two categories:
So, we have two types of charging technology in the field. AC is where the EV battery is charged by the car, and DC is where the conversion of the electric grid alternating current to direct current is done by the electric vehicle charger. There are also DC chargers with lower power ratings ex. 20kW but I’m not focusing on the DC technology that much in this post.
The AC charger is communicating with the electric vehicle (EV) using a standard called IEC61851. The main function of an AC charger is to provide electrical safety features between the vehicle and the electrical grid. So, in plain terms, an AC charger is an advanced electric switch with built-in safety mechanisms and advanced services and features are provided by the EV charging platform.
It is important to understand that the most advanced features of electric vehicle charging service lay in the EV charging platform and the charger is simply following the commands delivered by the EV charging platform.
AC Charger consists of the following overall components.
The strength of the housing is measured with an IK-value. This stands for impact protection and the value range is from 0-to 10 (where 10 is the best protection). For EV Chargers the minimum value should be IK08, but in many cases, manufacturers produce IK10 units.
The water and dust resistance of the casing is measured with an IP value. This stands for ingress protection and the value is two-part. The first digit stands for protection against solid particles like dust and the second is for liquids like water. The range is from 0-to 9 but there are also additional markings possible. More on that here
On EV Chargers I would choose a unit with an IP rating that is at least IP54, but you can install units with IP44 or indoor (parking halls) even lower.
The housing of the charger is also what affects most how easy the unit is to install. The housing dictates the mounting points for wall or ground installation. It also dictates the routing of the feeding cable from the electricity network into the charger.
In Europe, this is a Type2 socket or cable. You can select your product with a socket where the EV driver carries their cable with them and uses that to connect the car to a charger or fixed cable charger where no additional cable is needed driver just uses the cable attached permanently to the charger. Fixed cable is certainly more user-friendly and should be considered whenever possible.
"fixed cable is more user-friendly"
The controller is the brain of the unit. It is an electronic device that is communicating with the vehicle and at the same time commands the electricity on or off towards the vehicle.
Picture: Bender EV charging controller, also certified by eMabler
The controller unit is using an electrical device called a contactor to open and close the electric circuit towards the vehicle. These contractors can be a separate component in the charger, or they can be soldered directly on the circuit board of the controller.
The charger controller is also providing outbound connectivity for the charger. This means there is usually an internet connection capability from the controller. This is done either with ethernet, Wi-Fi or a 2/3/4/5G modem. However, many 2G (GSM/Edge) networks are soon phased out and therefore 4G is currently the best option - 5G likely in the future. This is also why many chargers have an antenna for wireless communication. Also, the accessibility of the ethernet connection connector is crucial when thinking about how easy the unit is to install.
There are a few mandatory components that EV chargers need to have.
The chargers should provide a way of communicating thru an internet connection. There is standard wired connectivity like Ethernet wiring. If using wired connections on your chargers couple of rules to follow:
You can also make the connection wireless with the chargers. Here are some rules to follow if using wireless communication like Wi-Fi and mobile data networks.
Communication with an EV charging platform is done with a protocol called OCPP which stands for Open Charge Point Protocol. It has been developed by a consortium called Open Charge Alliance.
Although it’s a relatively widely used standard (as it has been adopted by the whole EV charging ecosystem) it has limitations. For example, it does not strictly describe charger configuration parameters. These types of things that are open for interpretation has led to the need for interoperability testing against charger manufacturer device and EV charging platforms.
Currently, the most popular OCPP variant is 1.6J, but soon, more EV chargers with OCPP 2.01 will arrive on the market. We work with different EV charger providers to ensure the chargers work properly with the eMabler API-First EV Charging Platform - now and in the future.
The connection of a charger to an EV charging platform starts by installing the unit and making proper wiring or wireless setup on-site. The second part is commissioning the unit. This consists of specifying to the device what connection method to use, Ethernet, Wi-Fi or mobile data networks. Then giving the device a unique ID for it to communicate with an EV charging platform and finally provides the EV charging platform endpoint URL for the charger to start the communication.
All this can be done on-site after the power has been connected to the unit. There are several ways different manufacturers provide access to make these settings. It can be a mobile app connecting to the unit with Bluetooth, or a web page you can access directly from the unit if you know what IP address it got from your network setup. You might need to connect a separate USB cable between your unit and a laptop, or you might need to use a dedicated application on your computer to do the commissioning setup.
Commissioning can also be done in the factory where the unit is produced. This requires some commitment from the manufacturer, as they need to place the settings on the EV charger at the factory. If commissioning is done on the factory only thing left on site is to connect electricity and communication.
The reality is that installing and commissioning the chargers is still complicated. It takes time and errors happen easily. This is an area where eMabler can substantially help its customers, partners and EV charger manufacturers.
"installing and commissioning the chargers is still complicated"
End of this post I give you some pointers on what to look for when reviewing if a charger is good.
Ease of installation
Read the installation instruction provided by the EV charger manufacturer. This usually tells you much about how much time the manufacturer has spent thinking about the installation.
Ease of commissioning
I would say that commissioning is currently the weakest link of most EV chargers. Commissioning often requires the use of a computer on the site, special competence and several parameters that can make the installation fail.
Usability of the unit and its stability
This can be hard to estimate before the unit has been tested by us.
Price
Of course, the price of the unit plays a key role when comparing different manufacturers.
There is a lot to consider when choosing EV chargers for your network. We often help Charge Point Operators to develop their long-term vision i.e. how they want to develop their services and what to consider when choosing their EV chargers. Therefore, we recently launched the Charge Point partner program to ensure better reliability of EV charging services, a lower total cost of ownership and convenience for the EV driver.
We see the following trends in EV charging services:
Be careful not to build your EV charging service on a single provider but instead use modularity. Over the short history of EV charging, we have seen several hardware and platforms booming and then vanishing. Build your services so that you can over time develop them (even change providers) and stay competitive in the market.
In the upcoming hardware reviews, we use these key points as a basis for our valuation of different manufacturers' units. Hopefully, this post has shed some light on what EV chargers are, especially AC ones, how they work and what to take into consideration when comparing them.
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Based in Helsinki, Finland. We believe that eMobility is the way forward, having worked in the industry for over a decade and we see a great boom in eMobility. We’ve also seen many platform providers develop closed ecosystems and realized that there’s a need for a more flexible solution that focuses on end-user experience.
That's why we decided to build an open platform that lets you integrate your EV charging data into any existing systems, contact us.