With the cFos Charging Manager and a solar system, you can make sure that your car is (almost (*)) only charged when solar surplus power is available. Surplus = generation minus household consumption.
For this you can set up a charging rule of type "Solar". As mode select "Solar surplus". As "Start current limit" select the surplus current that the solar system should generate, from which this rule should apply.
Rule 2: Solar, Starting current limit: 6,5 A (6500 mA), "Solar Surplus", this activates surplus charging with the available surplus from an average feed-in of 6,5 A.
To decide if the charging rule is currently in effect, the cFos Charging Manager uses a rolling average over approximately 15 minutes for solar charging rules, so that charging is not interrupted during short-term power drops, such as those caused by passing clouds.
You can read these averages by using the virtual counter "Produced Power, Avg." for the solar charging rules in the Charging Manager, or by setting up the counter "Grid Demand, Avg." in case of surplus. If you observe these meters for a few days, you will find suitable values for the solar rules.
The excess electricity is the electricity that would be fed into the grid. In order to determine this, the cFos Charging Manager must be able to measure it. The following options are available for this:
The generation power can be measured with an extra meter. Alternatively, you may be able to read the values from your solar system directly. Please refer to our list of currently supported devices.
Note: If you use meters that record the current in phases, the Charging Manager can control the charging power in phases and thus optimize it (especially for cars that charge one or two phases). In the case of meters that only output one power value based on the number of phases used, the cFos Charging Manager allocates the power evenly to the phases, which leads to certain inaccuracies. In this case (and also in the event of sudden high consumption) you should set a sufficiently high power reserve.
(*) The use of moving averages can result in a slight grid reference or feed-in in the border area.
If you know that the solar system can generate 4.2 kW of power or less, excess charging must be configured with a workaround. In this case, "balanced charging" is applied.
Note: Electric cars need at least 1.4 kW (ie 6A) per phase in order to be able to charge. With three-phase charging, this results in 3*1.4 kW = 4.2 kW.
Below 4.2 kW of solar power, the power for charging must be redistributed from the three phases to one phase so that at least 1.4 kW is available on this phase. For example, if you feed in 500W of solar power on all phases, you can draw 1500W on a single phase. Since the bidirectional meters of the energy suppliers work on a balance sheet, there is no mathematical purchase of the grid or feed-in.
Below 4.2 kW you have to switch off two fuses with which the supply lines to the wallbox are protected (only not the one with which the cFos Power Brain Controller is protected). Caution: You may not switch individual phases on or off during the charging process. This can destroy the car's charging device!. If you do not use a meter on the wallbox that can resolve individual phases, you must inform the Charging Manager that the car is now charging in one phase by setting the "Phases" configuration parameter accordingly. With a counter that can resolve individual phases, you can leave the phase setting on "determine".
If you later want to recharge the car independently of the solar excess, switch on the switched-off fuses before charging and deactivate the solar excess charge rule in the Charging Manager. Then you can charge with normal power.
The control in a power storage always tries to minimize the grid consumption and the grid injection. You can tell this to the cFos Charging Manager by setting up a meter with the role "solar storage". In this case, a discharging storage is considered a generator (the meter shows negative power values), which means that this energy is available to charge the car. However, a charging storage (the meter shows positive power values) is not considered as a consumer because the storage stops charging immediately when the charging power is used for charging the electric car. So, for meters with the role "solar storage", the cFos Charging Manager ignores its consumption.
If your electricity storage does not have a bidirectional meter, you can install an external meter. Usually bidirectional Modbus meters are recommended, but, depending on the arrangement of the meters in the installation, it may also work with several S0 meters (or other unidirectional meters), which must be checked on a case-by-case basis.