My public 22 kW charging station

How do you get your own charging station?


The charging station itself was left over from Sm!ght, an EnBW subsidiary and is an in-house development. My charging station is an "EnBW LS 3.0" with the 3.2 doors that comply with the German "Eichrecht", which is a very complicated calibration law. Mine in particular was a remainder which I bought. Many people know the type and their relatives. Sm!ght started with a smart lantern. This was equipped with many sensors and measured, for example, the air quality. As a further extra, a possibility for charging electric cars was implemented. For example, such a lantern still stands at the Schwarzenbachtalsperre in the Black forrest. After the lanterns as a charging station were more exciting for many customers, the light itself was removed in further stages of development. This is ultimately the version I have. There is nothing left of the lantern and the sensors, it is just a charging station with the option of retrofitting a parking sensor. My charging station in particular was built in 2017 and was in test operation for the NetzeBW project in Freiamt (Germany) where they tested what happens to the grid when everybody in a street is driving electric.

The latest and last development from Sm!ght regarding the charging station has the well-known hump that the display is further down and the type 2 plug is in front. Which is ideal for wheelchair users.


Meine eigene öffentliche Ladesäule mit 2x 22 kW



But since Sm!ght gave up the AC charging station business, this station was left over and I was able to get hold of it at a very good price. Otherwise the station would have been scrapped. I also got a cage for the foundation.

Heidelberger now sells the heritage of the Sm!ght stations and develops them further with its subsidiary Amperfied GmbH.



Why not a cheap wall box?


In Germany we are fortunate that we have calibration law for charging stations, called German Eichrecht. If this only meant that calibrated electricity meters had to be installed, the calibration law would actually be a good thing. But it mostly overcomplicates things to the maximum. Since the station is older than calibration law, I first had to convert it to match with the calibration law. This is only possible with the components approved by the calibration office for this station. For this purpose, I had to remove fully functioning and calibrated meters and controllers and replace them with controllers that measured just as precisely and were minimally re-soldered. I also had to lay a few cables a little differently so that the path from the meter to the type 2 sockets was a few centimeters shorter. In addition, install doors with a larger display window so that you can see the values on the electricity meter even better.

However, I still wanted to have the station as a base, since this type has already been approved by the calibration office. That would not be possible with a standard wallbox. This fact alone is also why it should be difficult to do something like this yourself here in Germany. Because you can't just take any box and sell electricity to people, it has to be a "eichrechtskonforme" charging station and in this you can't even replace the ABB 32 A fuses with Hager 32 A fuses. Everything must be perfect as it was approved by the calibration office . Down to the last screw.



How do you connect a charging station?


We have an empty pipe in the foundation for the power and data lines. In our case, we laid 5x 16mm² cables from the house connection to the charging station.

Fuses and the like are in the charging station itself. In principle, it also has its own house connection box, so that you could also connect it directly from the public power grid and install your own electricity meter. But then we would have to pay for an additional house connection and dig up the street. Therefore, the internal house connection of the station is looped through, behind it are the fuses for the type 2 sockets and the internal electronics.

The house connection is also one of the reasons why it is a type 2 station. Of course we think CCS is super cool. But that is firstly much more expensive to buy and secondly the house connection would not go along with it. A battery-buffered solution would of course be even cooler, but we don't want to invest that much.


But because the charging station runs on our house connection, we also installed a Siemens electricity meter directly after the electricity meter in the house. The charging station can throttle if we are charging a private car in our garage and there is too much going on at the station. Usually, however, load management does not have to take effect, it is simply a safety measure. Even if the station can deliver 2x 22 kW, there is usually a maximum of one car charging and only at peak times there are two, although 90% of the cars can only do 11 kW anyway. I have already reported here in detail how the load management works. In addition to the two public charging points, we also have 5 private charging points. Also with load management.


smart #1 & VW BuzzID



When supplied with electricity, the charging station also needs access to the Internetnet. In normal operation on the street and with its own power connection, you would simply let it run via the integrated SIM card. But since that would also be additional monthly costs and we already have a network in the garage next door anyway, we connected the station via Ethernet.

The data connection runs via this access. So the exchange with the backend, the message in the apps whether it is free and also the activation via app.



How do you bill at the station? What does the electricity cost?


What the electricity costs depends in principle on what kind of provider you use it with. The station itself runs via the backend from next step mobility GmbH. They also took care of registering the charging station and all the bureaucracy on the subject.

You can use the charging station via all charging station apps and providers, roaming works on it like you know it from any other public charging station. Everything is possible, from EnBW mobility+ to Maingau and cards from foreign providers. The billing then works via the backend of next step mobility GmbH and we get the fixed kWh price agreed with them. It doesn't matter who charged at it. Because we don't charge blocking fees, we don't get them. I have already explained in detail in this article how exactly the money comes from the customer to the station operator. Here is the info graphic again:


Weg des Geldes Infografik EN



I can't give exact prices. But in general there is a monthly amount to be paid for the backend and then of course we get something for the kWh sold and charging processes. Thanks to our own house connection and network, there are no monthly costs.



Is my charging station financially worth it?


No, it's not. In order to cover the costs (electricity & backend), approx. 120 kWh must be sold monthly. This corresponds to an optimistic 6 charging processes, more like 8. About 200 kWh run through the charging station every month. This results in a "profit" of €25. That never pays for the station, the conversion to conformity with calibration law, the paved area in front of it, the installation and supply line or even the lighting for the charging station. All this sums up to an investment of about €15-20,000 at regular prices. Let alone spare parts, should something break and regular maintenance every 12 months. And we are already at a relatively well-frequented charging station. In our village there is a holiday park, campsite, gym and an outdoor pool, all within walking distance. In addition, we have very low monthly costs, if the station needed a SIM card and its own power connection, it would have to sell a multiple of the electricity to be able to cover its own costs.


Another difficulty is, of course, being able to operate and configure such specific hardware. Without the former Sm!ght employee Simon Gutjahr, who now works at EnBW in the mobility+ team, I would not have been able to put the station into operation, maintain it and install any updates. Then I would have to switch to something completely different, which would definitely be even more expensive to buy and I would also need paid support from the manufacturer.


Meine eigene öffentliche Ladesäule



Why operate a charging station if it's not worth it?


It was clear to us from the start that the station would not be worthwhile. Before we had this, we had a NewMotion box that did not comply with calibration law and was therefore free. From this we already knew how the demand would be. We set up the charging station because we enjoy it and are curious. There are some quite exciting experiences that you have with such a charging station. Also, both my father and I are in the charging business, so we already had the network to pull this off and knew how it basically works. Nevertheless, there were still many new things for us during the construction. There's a difference between being in project management and standing there with a shovel digging the foundation. It's also exciting to see how it's used.


For example, we have observed that a paved space in front of the station appeals to significantly more people than just a gravelled one. Nevertheless, some people ask whether the station is public or just for us. It is also interesting to see how regular customers use it and that they usually have very predictable routines.


For photos on the website and, for example, to try out the load management, our own cars are occasionally charge at the station. We have a charging card for this, which the backend knows and we can then charge our electricity free of surcharge. We just pay what we would pay for it on our private wall boxes. But it is clearly intended for the public and the majority of them are also involved. For us it was very important that the station appears in the usual apps and can be unlocked with all cards.

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