Solar installation for electric cars

Charge an electric car with photovoltaic electricity and save money.

Charging an electric car with solar-powered electricity: How do I save money?

In light of feed-in tariffs declining and electricity costs rising, self-consumption of photovoltaic electricity is becoming increasingly important. Instead of feeding the electricity you’ve produced yourself into the grid for a low profit*, you should consume or temporarily store as much electricity as possible yourself.

The savings for each self-consumed kilowatt hour today is up to 26 ct., since you don’t have to purchase expensive electricity from the grid (electricity costs: up to 33 ct/kWh) or store your self-produced PV electricity temporarily in the power grid at high cost.

Flexible consumers play an important role in being able to use as much of your self-generated electricity as possible.
An electric car is particularly well suited to this purpose, since an electric vehicle is usually stationary for far longer (22 hours per day on average) than it is charging. This means your electric vehicle can be flexibly charged at a time that suits you, helping to ensure that as much of the PV electricity you generate yourself can be used.

* The feed-in tariff in Germany for new installations in July 2022 is 6.23 ct/kWh for installations generating up to 10 kWp, 6.06 ct/kWh for installations generating up to 40 kWp and 4.74 ct/kWh for installations generating up to 100 kWp.

Solar installation for charging your electric car: What are the advantages?

Increase PV self consumption Increase PV self consumption

Increasing PV self-consumption

In light of feed-in tariffs decreasing and electricity prices increasing, it is no longer economical to purely sell PV electricity. You should therefore use or temporarily store as much electricity as possible yourself.

Cutting costs for charging your vehicle Cutting costs for charging your vehicle

Cutting costs

Self-generated PV electricity gets your electric car moving at a cheap rate. You save 26 ct/kWh in costs compared to drawing electricity from the grid. 

Protect the environment via green energy Protect the environment via green energy

Protecting the environment

When you use electricity generated from renewable energy sources, greenhouse gas emissions can be reduced by up to 70 % over an electric vehicle’s total useful life.*


Charging an electric car with solar-powered electricity: What do I need for that?

Make use of solar energy for your electric car Make use of solar energy for your electric car
Charge your electric car with power from your solar installation Charge your electric car with power from your solar installation

If you’d like to efficiently charge your electric car from your solar installation, you need a system consisting of three components

Icon: Additional meter Icon: Additional meter

Additional meter

  • Installed behind the ESC meter; measures the surplus electricity. 
  • Passes this data on to the smart control system. 
Icon: Smart control system Icon: Smart control system

Smart control system

  • Processes this data; uses the data to create the charging strategy. Also considers other factors (departure time, desired state of charge, etc.)
  • Passes the charging strategy on to the charging station.
Icon: Charging station electric car Icon: Charging station electric car

Charging station

Implements the smart control system’s charging strategy and communicates with the vehicle.

Your system doesn’t necessarily have to comprise three separate pieces of hardware. Some charging stations already have the smart control system integrated, enabling them to create their very own charging strategies. If your charging station does not have a smart control system, you can use a solar manager (also known as an “energy manager”). It processes the data from the auxiliary meter and develops the strategies for several consumers.

The schematic diagram below shows the PV installation’s potential consumers. In addition to the charging station, the home and electricity storage device can also be connected to the solar-powered electricity. In the future, the electric car will even be able to replace the domestic electricity storage device shown here. This technology is known as Vehicle-to-Home (V2H)

Infographic intelligent control system for charging solar energy Infographic intelligent control system for charging solar energy

Supplying your electric car and private household with solar-powered electricity

1. Installing a solar solution

The Calabrese family lives in a single-family home and recently started driving a VW ID.3. The family would preferably like to charge the vehicle using the photovoltaic installation mounted on the roof of their home, so they can make use of the solar-powered electricity the installation generates to the greatest extent possible and therefore be entirely emission-free on the road as often as possible. To use the solar-powered electricity, the Calabrese family has installed a solar solution consisting of an auxiliary meter and a smart control system.

2. Charging electric car with solar-powered electricity

This solution will allow the Calabrese family to supply an electricity storage device, their home and a charging station with electricity from the photovoltaic installation.
Having an appropriate usage profile (of both the electric car and auxiliary consumers) is critical if they are to consume as much of the generated PV electricity as possible themselves. Appropriate solutions, such as electricity storage devices, can help with temporarily storing excess PV electricity for subsequent use.
Based on their driving and charging profile, the Calabrese family can cover 70 % of their electric car’s energy needs using solar-powered electricity.

3. Saving money and driving emission-free

Given the VW ID.3**’s average consumption (20 kWh/100 km) and annual mileage (10,000 km), it would require 2,000 kWh of energy annually. In this case, 1,400 kWh could be covered by self-generated solar-powered electricity, enabling emission-free travel over 7,000 km. Assuming a maximum cost saving of 27 ct/kWh, this results in an annual savings potential of approx. € 380.

You can find more tips on how to save money with your electric carhere.

**Reference vehicle: VW ID.3, consumption according to the General German Automobile Association: 19.3 kWh/100 km, rounded up for the sample calculation. Charging losses were not taken into account here.

Charging solutions for charging with solar-powered electricity

To find the right charging solution for charging with solar-powered electricity, it’s helpful to figure out which of the above items you already have, and which ones you still need. If you already have individual components at your disposal, you must take special care to ensure that new individual parts are compatible with your existing system.

Looking for a charging station that’s compatible with your existing system?

We have individual components that will complement your system perfectly.

You can find an overview of the individual systems’ compatibility here. Excel auf EN?

FAQs: The key questions about charging with solar-powered electricity

Do I have enough solar-powered electricity to charge my electric car?

Generally speaking, an electric car is sitting idle for a very long time when it’s parked at home. The amount of energy required to cover the daily driving distance is very small in comparison. This gives you the flexibility to charge either at a lower charging power and/or at certain times, depending on the solar surplus. So you can still charge your electric vehicle with some PV electricity when you’re out during the day and come back from work in the afternoon. The average daily mileage is 50 km. With a charging power of 4.2 kW, you could recharge this required range in less than two hours.

What is the difference between single-phase and three-phase charging?

A vehicle needs at least 6 amps (A) per phase to start charging. Some vehicles even need 10 A. This translates into a minimum charging power of 1.4 kW for single-phase charging and 4.2 kW for three-phase charging. Charging stations generally have a three-phase connection. This means the charging process would only start at a surplus of 4.2 kW.

Some PV charging solutions can therefore switch between single-phase and three-phase charging with a view to charging even with a smaller PV surplus. In fact, for private individuals, the majority of charging takes place with 100% PV electricity in the single-phase range.

Explanation of the figures below: The figure on the left shows a charging solution without any phase changeover. In this situation, you would only charge the current proportion of electricity marked in light blue. The figure on the right describes a charging solution with phase changeover. Here, the proportion of electricity marked in dark blue could be available for charging too.


Solarstrom laden ohne Wechsel zwischen einphasigem und dreiphasigem Laden Solarstrom laden ohne Wechsel zwischen einphasigem und dreiphasigem Laden

Image source: SMA - Abbildungen auf EN?

Solarstrom laden mit Wechsel zwischen einphasigem und dreiphasigem Laden Solarstrom laden mit Wechsel zwischen einphasigem und dreiphasigem Laden

What are the charging strategies for charging with solar-powered electricity?

An ideal PV charging solution should offer the following three charging strategies outlined below as a bare minimum.

Icon: PV-Ueberschuss Laden Icon: PV-Ueberschuss Laden

PV surplus only

  • Charging with 100% PV electricity
  •  Starting and stopping the charging process depending on the PV surplus
  •  Charging power depending on the PV surplus
Icon: Strommix Icon: Strommix

Electricity mix

  • Additional decision variable 
    • Specified amount of energy
    • Specified distance
    • Dynamic electricity tariff
  • Prioritized PV electricity charging, adding electricity drawn from the grid if necessary. 
Icon: Maximale Ladeleistung Icon: Maximale Ladeleistung

Maximum power

  • Charging with maximum possible power, regardless of where the electricity has come from.
  • In case a lot of power is needed fast. 

Can I charge my electric car with a balcony power plant?

In principle, balcony power plants are unsuitable for charging an electric car. In Germany, balcony power plants offer 600 W maximum power at present. For many electric cars, this does not achieve the minimum power required to start the charging process. So it doesn’t make sense to use a balcony power plant to charge an electric car.

Are you looking for individual consultation? We would be happy to support you.

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