How to charge my electric car at home with solar power?
To charge your electric car with solar power, you need a photovoltaic (PV) system, a charging station (wallbox) and optionally a battery storage and an energy management system.
You should know that without battery storage you can only use solar power at the moment it is produced. If you want to charge your electric car with solar power, the most effective way is during the day when the sun is shining. In addition, the PV system must be sufficiently large to cover both the electricity demand in the house and to charge the electric car. e-cars are charged with at least 1,4 kw for technical reasons. This is how much power should be left after subtracting the household demand. the higher the power of your solar system, the greater the share of solar power in the electric car. If no solar power is available, your car will be charged with electricity from the grid.
Can I charge the electric car at a normal socket??
Theoretically, charging is possible at a standard household earthed socket, but this should not be assumed not recommended for safety reasons. Household wall outlets are not designed for hours of continuous use under high currents greater than 10 amperes and should therefore be only in emergencies used for charging electric vehicles. They can overheat and become a safety hazard. You should always prefer a permanently installed charging station. In addition, the charging power of 2.3 kilowatts (kW) is low and it usually takes more than 10 hours to fully charge a standard e-car battery.
Why is it worth having your own charging station?
The most important link between the PV system and the electric car is the charging station, also called a wallbox. Wallboxes are specially designed for charging electric vehicles. The usual charging power ranges from 1.4 kw to 22 kw (for home use). This results in average charging times of 2 to 6 hours, which depends not only on the power of the wallbox, but also on the charging power of the electric car.
What to look for when buying your own charging station?
When selecting and purchasing a wallbox, be guided by the requirements of your e-car. Wallboxes are available in various designs: they differ in their construction, charging capacity, plug type and purchase cost. There are charging stations with sockets in which the cable carried in the car is connected. More common are wallboxes with a fixed cable and plug, which is plugged into the car like at the gas pump.
Can I connect and install a charging station myself??
No, charging stations may only be installed by a specialist electric company and must be registered with the grid operator in advance or, if necessary, must be. Approval. It is best to have the existing electrical installation checked in advance. If possible, always choose a larger cable cross-section (or, if applicable. empty conduits) than is actually required for the current charging station. The effort required to expand the charging capacity at a later date is then much lower. You should contact the specialist companies directly on this point.
Where the charging station must be installed? What do I do if I don’t have a garage or live in a rented apartment??
A home charging station is best installed in the immediate vicinity of your own parking space. The charging cables – some of which are installed on the wallboxes – are available in different lengths. The exact length you need must always be weighed up individually.
Consumers without a fixed parking space (also known as "lantern parkers") are currently dependent on public charging stations, which are currently offered by various parties (municipalities, energy supply companies and automotive companies).
Tenants with a permanent parking space or underground car park on the premises of the housing complex can now request the installation of a charging station from their landlords at their own expense. Basis for this is the § 554 BGB. A guide to the acquisition of a domestic wallbox for tenants and owners can be found on the ADAC website.
Which charging power is the right one for the charging station??
Wallboxes are available with 11kw and 22 kw power output. The higher the power of the charging station, the faster the vehicle battery can be charged.
A 22 kw wallbox charges twice as fast as an 11 kw one, provided that your e-car’s charging system can also handle 22 kw of power. The indicated power of a charging station refers to a 3-phase charging. However, some e-vehicles only have a 1-phase charge controller. This means that, for example, with an 11 kw wallbox, only a maximum of 3.7 kw (with 16 amp fuse) can flow – i.e. one third of the rated power. Here’s what you should consider when choosing a car and a wallbox, especially if you want to charge as quickly as possible.
Wallboxes fall within the regulatory scope of the low voltage connection ordinance (NAV). There is an obligation to register from the grid operator and from 12 kw (§19 NAV) one Permit requirement. Please note that a wallbox with an output of 11 kW is subject to registration with your network operator, and a wallbox with an output of 22 kW is also subject to approval.
Are there subsidies for charging stations??
Wallboxes are currently subsidized by the kfw-forderbank of the federal government from tax funds. A prerequisite for applying for the subsidy: the electricity used for charging must come from renewable energy sources, for example from your own PV system or from an eco-electricity tariff. 900 € subsidy per charging point (a charging station can also have several charging points). Support is available for wallboxes with a capacity of 11 kW that are intelligently controlled and can communicate with other components of the power grid (e.g. energy management system or smart meter gateway). Energy management systems are also eligible.
Please note that any installation work – even if it is only for the laying of cables for the electronics – should only be commissioned after the application has been approved. Otherwise your application may be rejected.
Further subsidies from the federal state, the municipality or from your energy supply company are also possible, however, these are usually not combinable with the kfw subsidy. The funding landscape is constantly changing. check your options, which subsidies are possible, which can be combined and which are applicable for you as a private household!
Do I need a second electricity meter?
The installation company should always consult with the local power company beforehand to determine whether a charging station can be installed at the desired location and, if so, under what conditions. This is always a case-by-case decision by the grid operator.
If you have large electricity consumers such as instantaneous water heaters or night storage heaters in your house, the existing electricity meters may be overloaded with a higher load from the e-car. Therefore, especially for larger charging stations (e.g., solar panels), some grid operators might consider the use of an energy management system.B. 22 kw) require a separate electricity meter, which then requires an additional electricity contract and metering space.
As soon as the electricity for the electric car is billed via a separate meter, the solar electricity can no longer be used directly for charging the electric car. You would then have to work with your electrician to find a solution for using your own green electricity for the vehicle after all. One possibility could be a smaller charging station to avoid the additional electricity meter.
There are also charging stations that already have integrated electricity meters. However, these must be billable. You can also obtain information on this from the specialist or manufacturing company. If you have no choice but to install new meters, this will make the installation much more expensive.
Is it worth having a battery storage system to increase the amount of solar power used for charging??
To increase the proportion of solar power in your e-car, you can also purchase a betterie storage system. This stores the electricity produced by the PV system during the day and also makes it usable at night.
From an ecological point of view, a battery storage system makes sense, but as of mid-2021 it is not yet very economical.
The purchase costs of a PV storage system are still too high compared to the amount of electricity you can save by using it.
What are the advantages of an energy management system??
For optimal use of solar power from the PV system and battery storage, it is advisable to purchase an energy management system. These controllers can adjust the charging speed of the car to the current output of the PV system. If there is a lot of solar power left, the charging speed is increased; if there is little sunshine, it is automatically reduced. More detailed information about energy management systems can be found here.
Bi-directional charging: using the electric car as a power source
Bi-directional charging means that e-cars can not only be charged with electricity, but can also be available as a source of electricity. Prerequisite for bidirectional charging is that the wallbox and the vehicle also support it. Combined with intelligent energy grids and management systems, renewable energy can potentially be used more effectively in the future. The technical requirements for bidirectional charging are available, but not yet implemented in the market. For widespread applicability, there are still many regulatory issues that need to be fundamentally clarified.
Two models that could be implemented in practice in the future are V2H – vehicle to home and V2G – vehicle to grid. With V2H, e-cars can be used as a source of electricity at home. V2G refers to the linking of the electric vehicle with the power grid, so that it can also feed in power when needed. However, the latter is not so easy to implement in practice and may only play a role in the future.