Car Park and Workplace EV Charging – who needs 22kW?

Electric vehicle charging can take place using either AC (alternating current) or DC (direct current). Most chargers installed in homes and workplaces tend to be AC chargers, these are cheaper to source and install, and are normally a maximum of 22kW per socket/outlet. DC chargers tend to be available at service stations and dedicated sites, and can be anything from 30kW to 400kW+ per outlet.

I need to install multiple EV chargers in my car park / workplace, what would you recommend?

The answer to the above question is not straightforward, if you require an extremely quick turnaround and charge time, then dedicated DC charging points are the way to go – however, these units are relatively expensive, and can require a huge electricity supply per outlet. For normal office-type workplace car parks, where people are going to be in the premises at least 3-4 hours per day, then multiple AC chargers are going to make more sense, and it will give more colleagues access to charging points.

Do we need 22kW per EV Charging socket?

22kW per socket is NOT always necessary. There are relatively few cars on the market which can charge using the full 22kW AC capacity. A 22kW charger sends AC electricity to the vehicle, however batteries require DC electricity to charge. Each vehicle has an ‘onboard charger’ (OBC) which converts this AC feed to DC, this OBC is the limiting factor. When using AC charging your vehicle can only charge at the maximum power the OBC can handle (DC charging bypasses this OBC altogether, but can be harsher on the battery). All electric vehicles can use a 22kW AC charger, but most won’t be able to make use of the full 22kW available.

22kW AC chargers require three phase electricity, and having multiple 22kW chargers may use up your available capacity very quickly. It can make more sense to spread the available capacity over multiple single phase 7.4kW chargers, these chargers can still add around 40-48 kilometres (25-30 miles) of range for every hour on charge – more than enough to cover the average commute.

For example, instead of installing six 22kW EV Chargers, this same capacity would cover eighteen 7.4kW chargers – allowing more people to charge at the same time.

 

For more information on charging your EV, and how long it takes: How long does it take to charge an electric car at home? | EVBox