Charging an electric car at home: how it works with your own wall box
- Stromverbrauch, kWh/100 km: kombiniert 13,8 - 12,9; CO₂-Emission kombiniert, g/km: 0; Effizienzklasse: A+
Charging an electric car at home: how it works with your own wall box
Would you like to upgrade your garage or carport into a private charging station for your electric car? Then you need to keep a few things in mind. These are the most important tips.
- What are the costs
- What are the construction requirements
- What do you have to consider when installing a wall box as a tenant
- Why it makes sense to choose a green electricity plan for charging your car.
Is the 230 V household socket adequate for charging?
You can connect your electric vehicle to the standard 230 V household sockets. The charging process takes the longest with this connection. Because the standard household socket outlet is not designed for continuous operation, high temperatures can occur in the cables. Especially in older houses, which often have outdated electrical wiring, always have an electrician confirm whether the technical conditions are adequate for a charging station and what additional measures need to be taken to ensure safe charging. Given these restrictions, the standard socket outlet is only suitable for short-term charging when out and about.
When do I need a wall box?
The wall box is a special charging station for electric vehicles and is safer, more efficient and, above all, faster than a simple household socket. The wall box is primarily distinguished by its higher performance, i.e. more kilowatts (kW): instead of 3.6 kW from the household socket, the wall box provides 11 kW. The wall box is connected to the 400 V connection and installed on the wall in the garage or carport for the electric car. In addition to the name ‘wall box’, other less common names are also used for the charging station such as ‘wall charging station’, ‘wall connector’ and ‘home charging station’.
The Type 1 and Type 2 plug variants are the most widespread wall boxes. Here, too, the speed makes the difference: with a type 2 plug, every electric vehicle can be quickly recharged via both private wall boxes and at public quick-charging stations. This is one of the reasons why it is the first choice of most car manufacturers in Europe. Also important: the cable length needs to be planned generously as the charging socket may be in different locations, depending on the vehicle.
Can I also install a wall box as a tenant?
As a home-owner, you have free reign when it comes the installation; on the other hand, in a home owners' association you may need permission from the association to install a charging station. This can be done at the annual owners' meeting. Add your request to the agenda ahead of time and have the other members vote on it.
In principle, you can also install a charging connection in rental apartments. However, certain requirements must be met. First of all, you should clarify the matter with the landlord, and discuss whether he would be prepared to bear part of the costs. After all, this upgrades his property for the future. In addition, the billing modalities have to be clarified, i.e. which meter is used for billing and what happens to the charging station after you move out.
In an apartment building, you need a fixed parking space as a prerequisite for the installation, such as a parking space in an underground car park. Then you need to clarify whether the necessary power cable is available. As a rule, the user must also bear the costs of the installation. Whether this is worthwhile has to be calculated on a per-case basis.
What does the calculation for a wall box look like?
Typical charging stations for private electric vehicle users cost between 700 and roughly 2000 euro. The low priced boxes are only fuse boxes with cables and without any further features. In contrast, the more expensive models measure the power consumption, can be shared with several tenants and the consumption can be classified accordingly. The smart boxes can be controlled via an app and also require Wi-Fi access. In addition to the costs for the wall box itself, there are also the costs for installation by a qualified electrician. The amount of these installation costs depends on various parameters:
- How far is the box from the fuse box?
- How many wall openings must be made for the wiring?
- To what extent must cables be laid?
Which structural requirements must be fulfilled for wall boxes?
A three-phase 400 V alternating current connection, the high-voltage connection, is important for the charging in your own garage. You also need this, for example, to operate an electric stove, so it should be present in every house. As a rule, having an electrician install the high voltage connection in the garage is not a problem. It is important that the wall charging station is connected to its own circuit, which is protected by a circuit breaker and a residual current circuit breaker (RCD). The separate FI switch costs around 250 euro. The FI switch is already integrated into some boxes. However, these models are usually more expensive than those without a switch.
What else needs to be considered when installing the wall box?
The wiring to the connections of the electric vehicles should be as short as possible and installed as close as possible to the vehicle. The supplied connection cables are usually 5 to 7 metres long. Ideally, the sockets should be placed approximately 1 to 1.5 metres above the floor so that the cables can connect almost directly to the socket.
Because many specific requirements have to be observed during installation, a specialist should always install the charging station. The local energy provider can also help when searching for a qualified electrician. Often, they also offer to carry out the assembly themselves – including installation and commissioning – or assist with hiring a qualified electrician. Volkswagen dealers who offer electric vehicles can also help to find a partner.
11 kW or 22 kW – What charging capacity do I need?
Wall boxes cannot be run on just any connection. In order to ensure that the mains power supplies the required power, it must be registered with the local energy provide a before installation. The standard 11 kW output is generally available without any problems. This is sufficient to charge the electric car’s battery overnight. Some electricity suppliers invoice installation costs for charging performance higher than this. So if you would like to charge your vehicle especially quickly and need A 22 kW connection, you have to take these additional costs into account and these can even exceed the price of the station and installation.
Is it worth measuring the power consumption of the wall box separately?
Measuring the electricity consumption of the electric car charging process separately is worthwhile in order to monitor the consumption. People who can invoice their vehicle costs to their employer or deduct them from their taxes probably require separate recording. Some charging stations already feature an integrated counter that fulfils this function. However, this does not always comply with calibration law. If you want to be on the safe side, the electrician can install a meter in the switch box for approximately 150 euro. This puts you on the safe side when it comes to the legal requirements.
According to estimates, 50% of electric car drivers charge their vehicle at home and 20% at work
Is electricity for electric cars cheaper or more expensive than household electricity?
If all technical requirements are met, you can order the electricity from any desired supplier. If you purchase the electricity for your house and electric vehicle from a single source, the electricity costs will also be identical. The average price for household electricity in Germany is around 30 cents per kilowatt hour. In addition, some energy providers also offer special vehicle electricity tariffs. In order to be able to use an energy plan like this, the electric car has to be charged via a separate meter with a ripple control receiver as a ‘controllable consumption device’, as it is referred to in the Energy Industry Act (EnWG). Meters like this are also installed on heat pumps or electric storage heaters. Naturally, the discount has its reasons: because electric mobility customers should primarily use the electricity at night when capacities are available. At peak load times, such as in the evenings or mornings, the network operator interrupts the power supply to the charging station in order to continue it at times of lower capacity utilisation. This can save around 5 cents per kilowatt hour. As a rule of thumb, anyone who considers the environment when recharging should definitely choose a green electricity tariff. This ensures that the emission-free car is charged using electricity generated in a coal-fired power station with fossil fuels.