If you want to operate EVSE behind the energy supplier's flat meter, the cFos Charging Manager must, as usual, regulate the power of all EVSE so that the house's connected load is not exceeded. In addition, however, EVSE and flat consumption (e.g. showering, cooking, etc.) must not exceed the flat's connected load. In this case, you can install an intermediate meter that measures the consumption of the flat (without the EVSE). You then enter the maximum charging current of the EVSE as a formula instead of a fixed value. E.g. for an 11kW EVSE 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 EVSE is designed and the current that remains in the home after subtracting the consumers. If you want to connect the intermediate meter so that it records the entire connected load, i.e. flat consumption plus EVSE, enter the following formula:
min(16000, 29000 - M3.current + E3.current)
Here E3 is the device ID of the EVSE in the Charging Manager.
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. 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 EVSE and groups so that the maximum house connection power is not exceeded. Now you can add more EVSE as devices and use the corresponding group number in their configuration. A group can also have additional generation and consumption meters that can increase or reduce the maximum charging current of the entire group.
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 EVSEes attached to it) as a single EVSE. As maximum charging current, enter the value in mA per phase with which all EVSE of the Slave Charging Manager are connected to a busbar. 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 EVSEs connected to it. By cascading Master and Slave Charging Managers, you can build very large systems.
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.