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Apartment building: Operating EVSEs behind the flat meter

If you want to operate wallboxes behind the energy supplier's flat meter, the cFos Charging Manager must, as usual, regulate the power of all wallboxes so that the house's connected load is not exceeded. In addition, however, Wallbox and flat consumption (e.g. showering, cooking, etc.) must not exceed the connected load of the flat. In this case, you can install an intermediate meter that measures the consumption of the flat (without the Wallbox). You then enter the maximum charging current of the wallbox as a formula instead of a fixed value. E.g. for an 11kW wallbox and a connected load for the flat of 20 kW, i.e. 29A per phase, like this:
min(16000, 29000 - M3.current)
Here M3 is the device ID of the above-mentioned intermediate meter in the Charging Manager. So the minimum current is taken for which the wallbox is designed and the current that remains in the home after the consumers have been subtracted. If you want to connect the intermediate meter so that it registers the total connected load, i.e. flat consumption plus wallbox, enter the following formula:
min(16000, 29000 - M3.current + E3.current)
Here E3 is the device ID of the wallbox in the Charging Manager.
Note: The cFos Charging Manager assumes that a flat and the wallbox have the same phase rotation with regard to the house connection. A meter that is used to measure the power of the flat is therefore not phase-rotated with respect to the flat.

Operating EVSEs in charging groups

Figure cFos Charging Manager with charging groups

If your installation consists of several sections that are limited in their supply line (e.g. by a busbar or specific wiring), you can set up a group for each section in the cFos Charging Manager. Add a device called "EVSE Group" in the Charging Manager. The number of the group is derived from the device ID. For example, if the device ID of the "EVSE Group" is E5, the number of the group is 5. It is best to give the "EVSE group" a meaningful name and description. As soon as the charging group is set up, a select box will appear for all other meters and wallboxes, with which you can set the group to which the device belongs. As the maximum charging current for the group, enter the value with which the group is connected per phase. The charging current that the Charging Manager allocates to this group is limited by this parameter. Furthermore, the Charging Manager limits the power of all wallboxes and groups so that the maximum house connection power is not exceeded. A group can also have additional generation and consumption meters or its own grid reference meter. This allows the maximum charging current of the entire group to be dynamically controlled depending on consumption or generation. Generators enter the group, but also the entire system, as a PV surplus, if applicable. As in the "main group", you can assign charging rules for PV surplus charging in the individual charging groups. You can also assign your own priorities within the charging groups. Each group has its own priority scheme according to the priorities you set for the individual wallboxes within the group. Groups can be nested, i.e. a group can in turn contain groups.

Network several cFos Charging Managers

Similar to the groups above, you can also use several cFos Charging Managers in a network. You can add a device of the type "EVSE Charging Manager Slave" in the cFos Charging Manager. Enter the IP address and port of another Charging Manager in your network as the address and port. The Master Charging Manager will then treat the Slave Charging Manager (and all wallboxes attached to it) as a single wallbox. As maximum charging current, enter the value in mA per phase to which all wallboxes of the slave Charging Manager are wired, i.e. the same value that you have also entered in the cFos Charging Manager Slave under the general Charging Manager settings as maximum total current. The slave Charging Manager can, as usual, have additional generation and consumption meters (on the busbar) that increase or reduce the charging current of the wallboxes connected to it. By cascading Master and Slave Charging Managers, you can build very large systems. You must activate load management in the slave. It functions as an independent load management system to which the maximum current is dynamically limited by the master.

Simulation - Can the cFos Charging Manager meet your requirements?

You can check for yourself whether the cFos Charging Manager meets your requirements and is suitable for your specific configuration by simulating a system of virtual EVSEs and meters. If a function is missing, please feel free to contact us. We are always happy to receive suggestions.
Set up EVSEs and meters of the type "HTTP Input" in the Charging Manager configuration according to your desired configuration (additionally, if required, groups, charging rules, etc.). Set the role of the meters according to your requirements (e.g. consumption, generation, grid reference). In order to be able to set values for these EVSEs and meters in the simulation, the device name must start with "Sim-", e.g. Sim-EVSE1 or Sim-Meter-Home-Consumption. Now click on "Simulation" in the main menu. A new page opens in a new tab or browser window. This allows you to observe the behaviour of the Charging Manager on the tiles on the start page and set values in parallel on the simulation page. Note: When you close the simulation page, all simulated devices are reset to default values (i.e. zero). If you run the simulation with a Charging Manager that is already in active operation, you must make sure that no power overruns occur. For example, you could simulate a meter for generation so that the Charging Manager thinks that more power is available for charging than is available at the house connection and thus possibly cause circuit breakers / fuses to trip.

On the simulation page, you can now specify values in the tiles of the devices, which the cFos Charging Manager then takes over and includes in its calculations. For example, you can plug virtual cars into the EVSEs and charge them and see how the Charging Manager distributes the available power to the EVSEs. You can define additional generators and consumers and assign values to them, etc. If you define a simulated meter with role grid reference, the simulation calculates the meter values of this meter based on the devices assigned to it, i.e. it takes all consumers and EVSEs as grid reference and all generators as feed-in. Storage units with positive power are considered charging, while storage units with negative power are considered feeding. The value of the meter for grid consumption is calculated from the sum of all consumers minus all generators. You can additionally specify an offset in the tile of the grid reference meter, to which the calculated grid reference is added.