EV chargers provide a grid connection in the form of a cable to recharge the batteries of an electric vehicle. There are four types, according to Graham Kenyon, managing director and principal consultant of G Kenyon Technology. The first EV chargers were made to plug into a standard socket, and the charger was included in the vehicle. To increase safety when charging, monitoring of protective earth and residual currents caused by faults were included in the charging lead. That is called Mode 2.
As greater range was required, and vehicles moved from plug-in hybrid to full battery types, demand on the electrical installation increased; a charger needed to understand how much power would be available to charge the battery, so the charger wouldn’t damage the battery. So the next evolution, Mode 3, increases communication levels over Mode 2, so the vehicle can understand the amount of power coming from the electrical supply and provides for communication between the charging point and the charger, which Kenyon refers to as handshaking, mimicking the old word from dial-up modem technology. AC charging systems take mains voltage at 230V or 400V for three-phase hook-ups, according to BS EN IEC 61851. Finally, Mode 4 charging, which is used for systems over 70kW, can potentially handle hundreds of Volts and hundreds of amps. The charger itself converts the grid’s alternating current (AC) to the direct current (DC) used in battery circuits. Electronics facilitates communication between the vehicle battery management system and the charger itself.
RELIABILITY
Whatever the complexities of their installation, chargers vary in their serviceability depending partly on the components used (and the capital cost), ranging from a single board on a relatively low-power charger up to replaceable modules on standard switchgear for higher-power units.
Kenyon argues that EV chargers’ reliability will improve as more units are produced. That’s a point echoed by EV charger supplier Vital EV, whose director Alex Roe says that a common misconception in industry is that they are fit-and-forget technology. He adds: “There is room for improvement on the integrity of the power modules. I think that will continue as manufacturers become more experienced in building and deploying them.” Still, Roe says that chargers should last for more than 10 years, according to the manufacturers’ claims (it supplies chargers from Kempower, Alpitronic, Autel, Heliox and Quench Power). Standard warranty is two years.
Roe recommends at least an annual check of the equipment, or more frequently depending on use. According to the director, the main serviced elements are the power module and the control module. The software needs updating; the unit needs cleaning, and may need air filters changing. The cabling needs to be tested and cleaned and replaced if necessary. The whole system must be tested with a vehicle.
Vital EV delivers such checks as part of contractual service level agreements. Their terms are negotiable but Roe recommends a level of coverage that includes four-hour technician callout and fix within 24 hours (the firm employs more than 20 mobile technicians). In the first instance, support is through a 24/7 call centre, which Roe says can diagnose and resolve many problems remotely.
SKILLS AND TRAINING
Roe says that this new industry of electric charging is not prepared for the scale of demand that is predicted; although the numbers of electricians employed now to carry out service and maintenance are sufficient now, they will soon be outnumbered. (City and Guilds estimates a 14-times expansion from the 35,500 charge points currently by 2030).
As a result, he is encouraging qualified industrial electricians to consider switching to work on EVs. The company is looking for those that have successfully completed an apprenticeship and hold a Level 3 qualification in electrical installations, and knowledge and understanding of the UK electrical regulations (18th edition). Advanced courses in test and inspection or in EV installation are bonuses, but not required. The company will provide additional training as well.
Kenyon adds that sector differences complicate electrician qualification routes. He says: “One of the problems with the electrical industry in the UK is that we find it difficult to have a universal electrician. It would be very different working on a baggage handling system to a domestic electrical system, in that what you can and can’t switch off, and the safety implications of that, compared to automatic controls.
“This is important because EVs are going to appear in lots of different places. It isn’t right to say that we have an EV specialist working in every installation on EV charging equipment. There are different hazards working in a street versus a private car park, and different hazards again in a public car park. It’s still something for employers to consider what is appropriate, not to take away from the basic existing electrical standards in the UK.”
He points out that last year City and Guilds launched three different qualifications for electric vehicle charging installations within standard 2921: design and installation of domestic and small commercial, design and quality assurance of large-scale and installation and maintenance of large-scale installations.
In other news, professional engineering institution the IET has updated its code of practice for EV charger installations. The new fifth edition, which was written by Kenyon, includes new legislation including Part S of the building regulations, which came into force in June 2022, as well as additional testing guidance and requirements about telecommunications.
Picking up that last point, the electrical expert adds: “For domestic and commercial charging points, there is a requirement for comms to be fitted, and they facilitate communication with the smart grid; that is required by legislation.” This is because EV charging is just the start of an evolution toward much greater interaction with the grid.
“There is a move for the district network operator to become a distribution system operator. It’s not just a grid through which electricity flows from the DNO to the consumer; it also goes from the consumer back to the DNO and maybe back to the grid.
“While this is happening at the domestic and commercial/industrial scale, there is also grid storage too. Major distribution transformers are having batteries fitted and plans are afoot in Leighton Buzzard for example for a solar farm to have onshore wind, and lots of battery storage, and that is associated with a park-and-ride facility working with electric buses, and the ability to charge vehicles while they are waiting. These things are being looked at in all different levels within the district network; not just locally but nationally as well.”