Uses for electricity meters


Electricity meters can be integrated in many places and fulfill different purposes in the cFos Charging Manager. The cFos Power Brain Wallbox and the integrated cFos Charging Manager (also available separately for Windows/Raspberry Pi) support all types of electricity meters listed below:

  • S0 electricity meter: The simplest and cheapest type of electricity meter. When connecting the S0 output, you must pay attention to the polarity, since nowadays it is usually a semiconductor output that only leads in one direction. Use a twisted pair of wires for this. If you do not register any pulses, you must swap the lines at the S0 input. An S0 electricity meter is included with our cFos Power Brain Wallbox. You can use this universally, eg for measuring the charging capacity, the house consumption or the generation capacity of your solar system.
  • Modbus Electricity Meter: Electricity meter supporting the Modbus RTU protocol. The cFos Power Brain Wallbox has an RS-485 connection for Modbus RTU. For the Raspberry Pi or Windows PC you need an RS-485 adapter (e.g. our Modbuskit.
  • Smart Meter: Often installed in photovoltaic systems. This is usually a bidirectional meter that is connected to the grid transfer point and can measure whether you are currently drawing or feeding in electricity. These meters usually speak Modbus TCP, ie if your photovoltaic system is connected to your home network, you can address this meter directly.

There are phase-resolved and non-phase-resolved electricity meters. Phase resolved electricity meters count the electricity on each individual phase.
Meters with bidirectional measurement can differentiate between consumption and feed-in. A bidirectional electricity meter at the grid reference point is recommended if you want to charge excess solar energy (see below) or if you want to have an overview of your electricity feed-in/electricity consumption for your entire house with a photovoltaic system.

Grid purchase

You connect the electricity meter to the network transfer point. The cFos Charging Manager can then use this meter to determine the consumption or power generation of your photovoltaic system and calculate the solar surplus. If you have a photovoltaic system, you need a bidirectional electricity meter to charge excess solar energy. Alternatively, you can use the consumer-generator measurement method, ie you install appropriate meters for all consumers and generators.

Example of purchasing electricity

Consumption of the electric car/upgrading of third-party boxes

You can install the electricity meter directly in the cFos EVSE or connect the electricity meter behind any EVSE without an electricity meter. So you can keep an eye on the power consumption of a single EVSE. If you add a EVSE without an electricity meter to the cFos Charging Manager, you can clamp an electricity meter behind this EVSE. You can then add these as devices in the cFos Charging Manager and then attach them to the EVSE in the EVSE settings. A warging trash box with an attached meter appears to the cFos Charging Manager like a EVSE with an integrated meter. The cFos Charging Manager can then take into account the actual charging capacity of the car and thus charge intelligently.

Example for SunSpec solar inverters

Dynamic charging current regulation with consideration of house consumption

You connect the electricity meter in such a way that you measure the electricity consumption of the house without the cFos Power Brain Wallbox. The cFos Charging Manager will then reduce the charging power of your wallbox during peak loads to prevent overloading. This also works with multiple wall boxes. Alternatively, you can also use the cFos Charging Manager to set how much power is available to the house in total and allocate a fixed buffer. With an electricity meter, load balancing works dynamically and you can reduce your buffer. Dynamic charging current control with S0 electricity meter

Example of dynamic charging current regulation