Wallboxes are now available from a wide range of providers and grid operators. The registration portals of the grid operator are used to register an 11 kW wallbox. A wallbox with a charging capacity of more than 12 kW must be additionally approved by the grid operator. This is followed by the installation, which is best left to experts. Nowadays, complete services from registration to installation are offered from a single source by electricians. In the case of a rental property, it is helpful to discuss in advance with the landlord who will pay the costs of the wallbox installation.
The charging time at a wallbox is influenced by various factors, including the capacity of the wallbox, the charging capacity of the electric car and the current charge level of the vehicle battery. Wallboxes generally enable charging capacities of 3.6 to 22 kilowatts. The average charging time for the battery is between two and six hours. With a charging capacity of 22 kilowatts, the battery can be fully charged after around just two hours. A wallbox with 11 kilowatts charging capacity is sufficient for overnight charging. For charging times of eight to ten hours, the charging power can be reduced to conserve the battery.
It is not advisable to install a wallbox on a wall without the corresponding specialist knowledge. Ideally, the installation should be carried out by a specialist company. Electrical installations must comply with strict safety standards to minimise the risk of accidents and fire. Qualified electricians have the required knowledge to ensure compliance with these standards. In many regions, permits are required for the installation of charging stations. This should be taken into account.
The supply line from the power connection to the wallbox must be equipped for considerable charging dimensions to rule out overheating or even cable fire. The ideal ratio of cable cross-section, cable length and charging capacity is crucial for safe installation. As a basic rule: the thicker the cable cross-section, the more power is available from the wallbox. The cable cross-section of the corresponding wallbox cable type is specified in square millimetres (mm²).
Common cable cross-sections are: 2.5 mm², 4.0 mm², 6.0 mm², 10.0 mm² and 16.0 mm². With a charging capacity of 11 kW and a current of 10 to 16 amps, the minimum cable cross-section is 2.5 mm². If a more powerful wallbox is used for up to 22 kW battery charging with 32 amps, the cable cross-section must be 4 mm².
In theory, it is possible to charge an electric car via a 230-volt earthed socket. But this should not become the rule. With a charging capacity of 2.3 kilowatts, it takes between eight and 24 hours to fully charge the battery. Conventional household sockets are not designed for continuous high current. According to car manufacturers, normal household sockets are therefore only intended for emergencies.