Why a Wallbox is Preferable to a Domestic Socket, Image Source: Shutterstock Why a Wallbox is Preferable to a Domestic Socket, Image Source: Shutterstock

Many new electric car owners find it tempting to simply plug their electric vehicle into their domestic socket and start charging. The manufacturers even provide the necessary charging cable with many models. However, this cable is often listed as an “emergency charging cable” on the price lists. And for the following reasons it shouldn't be anything more than that.

Efficiency: Big energy losses drive up energy consumption and charging costs

It is impossible to completely avoid energy loss when charging an electric car. During the charging process, some energy is always lost as heat due to the electrical resistance of the cables and converters. Key factors that influence this small amount of energy loss are the diameter and length of the cable as well as the charging power and time spent charging. However, anyone charging an electric car via a domestic cable has to accept significantly higher energy loss, since the car's onboard charger only achieves optimum efficiency at high charging powers.

In the case of the Smart, the manufacturer Daimler lists different energy consumption levels for different charging scenarios. With the 22-kW onboard charger connected to a wallbox, the electric Smart needs - in ideal conditions - only 12.9 kWh for 100 kilometres of driving. When connected to a domestic socket, the reduced efficiency of the onboard charger means that the same vehicle will need 18 kWh of charging power for 100 km. The cost of this difference of 5 kWh adds up over time. At standard electricity prices, charging at the domestic socket costs a good €1.50 more per 100 kilometres. Someone who drives 10,000 kilometres a year in their Smart will see about €150 more on their electricity bill than someone with a wallbox installed in their garage.

Safety: Have your domestic sockets checked before connecting your electric car to them

For that reason, we expressly advise having conventional sockets inspected by an electrician if you want to charge your electric car with the emergency charging cable. Car manufacturers and electricians' associations also point out that domestic sockets used for electric cars must comply with the current safety standards. If you want to be on the safe side, a wallbox is your best choice.

Domestic sockets are often not designed for the high permanent load associated with charging an electric car. In some experiments, domestic sockets connected to electric cars reached a temperature of more than 80°C in only 15 minutes. In the worst case scenario, the supply cable can burn through and cause a fire.

Charging time: Quicker with a wallbox

With a wallbox things are much quicker. Even with a moderate charging power of 11 kW, the 60-kWh battery would be fully recharged in less than six hours, i.e. overnight or during a normal workday. With top-of-the-range 22-kW models, charging the same battery take less than three hours.

Current electric car models easily achieve distances of more than 400 kilometres. However, to make that possible they have correspondingly large batteries on board; 60 kWh or more is not unheard of. Since, for safety reasons, domestic sockets should charge at no more than 2.3 kW, charging with a home socket takes a long time. If you connect an empty 60-kWh battery to a domestic socket, you will have to wait more than 26 hours until it is fully recharged.

Only wallboxes can offer additional functions

There is no way around a wallbox if you want to use one of the many additional functions. A clever charging station offers extensive control and statistical functions, enables the convenient use of cheaper electricity tariffs at night and the efficient integration of a solar system or stationary storage system. Some features also make the charging process more convenient, such as user registration via RFID or built-in cables. In addition, many wallboxes have essential safety features built-in, including fuses and residual current sensors.

The Mobility House has a large selection of safe, quick and efficient wallboxes from many established manufacturers. Entry-level models start at just €600. Get in touch with us. We’re happy to help you find the best charging solution for you.

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