Charging rules

Screenshot cFos Charging Manager Documentation - RFID / PIN

Every few seconds, the Charging Manager evaluates the charging rules assigned to the EVSE and those of the users stored for this EVSE. Each set of charging rules for the EVSE and for the user is searched in the order entered. As soon as a charging rule applies, it is applied and all subsequent rules are ignored. If at least one charge rule is specified, but none is found, charge current 0 applies. This happens for the rule set for the EVSE and the rule set for the user. If a rule for the EVSE and for the user applies, the Charging Manager uses the lower charging capacity.

For each rule, you can specify the days of the week for which it should apply.
There are 3 types of rules:

TimeThe rule applies from the set start time to the set end time
InputThe rule applies when a digital input is set or deleted
SolarThe rule applies when the solar power (the sum of all producer meters) is above a certain threshold

Each rule contains a "Power" value and a mode.
The meaning of this "Power" value can be switched depending on the mode, in

AbsoluteThe value is considered as absolute wattage for charging
In PercentThe value is the percentage of the maximum power of the EVSE (here you would possibly go to percentage of solar power in a later software update)
Production Power AbsoluteThe value is ignored and the total solar power is taken as the charging power
Production Power in PercentThe value indicates a percentage of the solar power
Production minus PowerCharging power is equal to solar power minus fixed value
Surplus chargingThe documentation for this loading rule can be found on this page.

The Charging Manager interprets the result of the evaluation as a "wish" of the charging station for a certain charging power. This is distributed to the charging vehicles according to the available charging power.

With this system, for example, you can only allow charging within certain times:
Rule 1: Time: From 8:00 to 12:00 "In percent" 100

Solar controlled charging

Rule 1: Solar, 8,5 A (8500 mA) solar power, "Production minus Power" 1500, so charge when at least 8,5 A (8500 mA) solar power is available, but always leave 1,5 A (1500 mA) for the rest of the household.

Screenshot cFos Charging Manager Documentation - Surplus charging

Rule 2: Solar, start current limit: 6.5 A (6500 mA), "Solar surplus", this activates excess charging with the existing surplus from a feed-in of 6.5 A.
In both cases, you can specify a maximum time limit. This means that after the rule is active and the current limit is undershot, the rule is still used for the set time. This prevents the Charging Manager from switching off charging in the event of brief clouds.


The current strength is given by a formula, see instructions for formulas. The stream can be run as continuous. With the conditional operator you can switch the loading on and off.


Charging starts as soon as the electricity price is less than or equal to a value in euros. Alternatively, you can also specify a price level that must be reached. As an electricity provider with a variable electricity price, the cFos Charging Manager currently supports Awattar and Tibber. So that the price-based charging rule can be used, you have to select the energy provider on the start page, Settings of the Charging Manager. For Tibber you still have to request the OAuth token. For this purpose there is a Tibber web link under "Configuration", which becomes active as soon as you have selected Tibber as your energy provider. Tibber defines the price level as follows: Very expensive: 140% above 3 days average, expensive: 115% above average, normal: 90% -115% of the average, cheap: below 90% of the average, very cheap: below 60% of the average . The cFos Charging Manger takes over the price level from Tibber and calculates it accordingly for Awattar.


You can use a formula (see Formulas) to specify when the loading rule should be active. If the formula returns a non-zero value, the loading rule becomes active. It becomes inactive when the formula returns zero and the underflow time has expired. Meter values, inputs and charging manager variables can be queried using formulas.


You can also use charging rules with a switching input. The cFos Power Brain Wallbox, for example, has 2 S0 inputs. To use these, you can set up a cFos Power Brain S0 meter as a device with the "Display" role in the cFos Charging Manager. Assuming this meter has the device ID M1, you can address the S0-1 input with +M1#0 or -M1#0 ('+' means the rule is active when the S0 input is closed, '-' when it is open).

For example, if you want to control the charging current using an external switch, or if you use a ripple control receiver that switches a relay according to the specifications of the energy supplier, you can use the following charging rules:

Screenshot cFos Charging Manager Documentation - *** ml: String not found [name='cfos_cm_doc_a_inputs']

The 1st charging rule states that the car should be charged with 8A when the S0 input is open.
The 2nd charging rule ensures that the car is charged with 16A if rule 1 does not apply. So you are switching between 8A and 16A here. You can also use the 1st charging rule by setting 0A to pause the car if the relay is opened.

The 2nd charging rule is necessary (as explained above) because as soon as at least one rule is present, the charging manager sets the charging current to 0 if no rule applies. If you only want to charge the car when the input is closed and not otherwise (key switch), a charging rule with +M1#0 and 16A is sufficient.