Experience report: Electric car invite in community garage

Experience report: Electric car invite in community garage-community

Finally! The electric car has been there for 18 months. However, I can only load it on a household current connection of a neighbor, with which I have temporarily exchanged the parking space in our community garage. Ok, a continuous performance of one kilowatt ranges overnight too. Of course, a sustainable solution for the 52 parking spaces can not be. It had to be a last management. The research and phone calls were tedious and expensive. The standard OCPP (Open Charge Point Protocol) to German “Free Charging Point Communication Standard” sounds super modern. I did not want to do it. After all, we want to be future-proof.

But the solution had to be able to grow along, because in the first weeks I found only two other comrades. An initial investment of 20.000 € we did not want to stop threes. In addition, we did not want to have ongoing costs and avoid a high complexity. So we decided for a very simple and proven and scalable communication system. Communication between the Load Management Controller and the Inline Wallbox models simply runs over a data cable, also known as a telephone cable, which on SOG. Potential-free contacts is connected. The Wallbox reports that you want to load, the load management looks, if it still has electricity. If so, it sends the enable signal to the wallbox and already begins to load the chic new car.

But whether the connection power is really enough? The network operator wanted to provide us only 30 kW in continuous operation from the house connection capacity of 39 kW. So a bit was expected. And indeed: performance is sufficient for 50 vehicles when a load management is used. An average daily requirement per car from 5 kWh provided, all cars can be loaded purely mathematically in 8- 9 hours a day. There is even room for the solution of the SOG. Network. The network operator is throttling or pausing the power supply for a few hours in the evening to stabilize the entire power grid. For this he renounces the network fee of 4- 6 cents per kilowatt hour. This savings will reach us the electricity supplier. If necessary, the network operator would connect to a SOG. Convertible measurement for estimated 3.000, – Add to 30kWs.

The concept was prepared in a few weeks with the help of a specialist consultant and our electricaler and made a cost estimate. We wanted to start very small and expected that further neighbors would connect to our example. The entry into force of the reform of housing ownership rights, the Wemog Housing Ownership Modernization Act on 1. December 2020 gave us the necessary thrust. In an extraordinary owner assembly, our concept of a charging infrastructure was excelled without opposing. Then it could start.

The Last Management Controller for the first 10 charging points was purchased. Another thick working current cable was drawn, cable sprights over the joint passenger with the transverse parking spaces mounted and the first working current and data cables relocated to three parking spaces. There were two types of property. A community ownership of users on the basic installation and individual ownership of the cables, electrical components in the distribution box and the self-procured wallboxes at the parking spaces. After the assembly work started, further neighbors became attentive and then we were already six co-owners with seven parking spaces. The initial investment could therefore be shared by seven.

At the current scope of the basic installation, ten charging points / parking spaces can be operated. Then the investment costs are approx. 15.000 €. Any other neighbor who wants to participate in the educated user community is compensated for the old users part of their participation. This ensures that at least in the first few years before the depreciation, everyone bears the same proportion of the basic installation. This group of users who has given their own contract is open to all other neighbors who want to participate in the next few years and decades.


Electromobility and thus local emission freedom only makes sense if the electricity comes from renewable energy sources. It is best to produce as close as possible to use. So that would be the own photovoltaic system on the roof of the parking garage. In this example, 50 kWp could be installed, the CA. 50.000 kWh could produce a year. Material could be operated with the self-generated solar stream in conjunction with a memory and smart charging management over 25 E cars. However, the regulatory factory does not allow this (summer 2021).

The author Jurgen Conrads is ready for further information about the following mail address: NGLIS62 @ Web.DE (NGLIS stands for user community charging infrastructure). Simply write and refer to this article.

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5 thoughts on “Experience report: Electric car invite in community garage”

  1. Interesting insight and concept, thanks for the report. The average driving performance of cars in Germany is approx. 20.000km a year, ie ~ 55km a day. Averaged over the underground car park of an ownership community should be there for everyone more than enough electricity. I myself have been in my new building already put the stream in the garage, the wallbox is still missing for the manufacturer’s delivery difficulties.
    But I still have an interesting anecdote: a colleague of mine commutes 80km (one way) to work and could not come to any wallbox for months for months. In the beginning, something nervous does not bother him anymore. At the Schuko he can relax overnight loose. If it would not be “almost gifted” by promoting, he would not be installed anymore. The fewest people are likely to drive every day so far. Myself I have z.B. just under 10km to work, which I drive in fine weather with the e-bike.

  2. First of all, thanks to the author for the very good report on experience with our load management.
    If you want to find out the average charging power in a underground car park, this can be done with our online computer:
    https: // http://www.Eautolator.Net / calculator

  3. Very nice article. He shows that you can use a little connection power many vehicles. Let’s go from the average 13.600km per car from and a cancer consumption of 17 kWh (not everyone does a Tesla) then you need per car. 2.300 kWh per year. Only rarely does anyone invite much to and on the frequent driver comes in the community also a little driver.

  4. 30 kW for 50 cars? These are 0.6 kW, if everyone loads. Sure, 50 cars are not now, but maybe 5 and everything seems to be remotely. But if in eight years after the long weekend everyone wants to complete his battery to start the next working day, the system is exploded. And the batteries are greater. You will not rent more where there is no 11 kW per parking space.

  5. Our underground car park is about the same size but so far I’m the only one who wants a wallbox ☹️ all other silence or are reprint – with all arguments against the emotobility that is known.

    No matter, I’m doing the beginning and games the icebreaker – Due to the new law, I finally got the release of the path


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