cFos Charging Manager

cFos Charging Manager - load management for charging electric cars

The cFos Charging Manager is aimed at operators of parking lots that are to be equipped with wall boxes for charging electric cars. The aim is to provide the individual electric cars with as much charging power as possible, taking into account the available total power by means of load management - often without even having to increase the existing house connection power.

Note: We are currently seeing an increased volume of inquiries from homeowners' associations, multi-family houses and associated communal garages/parking spaces. Since it is often unclear to interested parties what the first steps in implementing load management look like, here is a planning aid for parking garages and a practical example of an underground car park.

Previous solutions are expensive and mostly limited to a specific provider of wallboxes. A manufacturer-independent system offers investment security.

The cFos Charging Manager allows you to set up your charging infrastructure according to your wishes. For this purpose, the cFos Charging Manager supports a number of wall boxes from different manufacturers by means of load management. We are constantly working on expanding the list of supported wall boxes.

To plan your charging infrastructure, first select the desired wall boxes. For large systems, the individual wall boxes should be as inexpensive as possible so that the total costs remain manageable. The cFos Charging Manager therefore also supports low-cost models and then makes any missing functionality of the wallboxes available elsewhere.

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Img Single family house with solar system

Single family house with solar system

1-2 EVSEs, Charging Agent, intermedita meter for home consumption measurement, S0 meter for EVSE consumption measurement

1 wall box with 22kW and instantaneous water heater would overbook the existing house connection capacity. Thanks to load management, the charging power for the car is reduced when someone is showering or cooking. With 2 wall boxes, the charging power would be distributed to both cars. Solar power is used to charge the cars during the day.

Img Garage 50 parking spaces

Garage 50 parking spaces

with go-e boxes and central ABB B24 (Modbus to Raspberry PI) in an apartment building

In several places in the garage there are RFID readers that communicate with the cFos Charging Manager

Billing and Authentication

OCPP wallboxes, like many other wallboxes, have built-in electricity meters that the cFos Charging Manager can read and make the kilowatt hours used available for billing. With simpler wall boxes, you can install your own meter. We recommend laying your own Modbus for networking the intermediate meters.

OCPP EVSEs typically have an RFID reader for authentication. Many other models also have their own RFID reader. In this case, you teach these EVSEs new RFID cards. Then these EVSEs check the RFID card and automatically activate the charging process. The cFos Charging Manager remains informed about the charging process and can regulate the charging power.

For EVSEs without their own RFID reader, release can be done via a Web interface of the cFos Charging Manager by entering a PIN. You can also connect an RFID reader to the cFos Charging Manager or network it with one or more RFID readers. The cFos Charging Manager then takes over authorization and release of the EVSEs. Mixed operation of EVSEs with and without RFID readers is also possible

Control of charging power

The cFos Charging Manager uses load management to try to distribute the maximum connected load installed in the building as well as possible to the electric cars to be charged. The cFos Charging Manager calculates the available charging power every few seconds as follows:
House connection power minus consumers in the house (e.g. apartments or machines) plus producers (e.g. solar systems).
Grid purchase (positive for purchase, negative for feed-in) minus charging power of the EVSEs. A bidirectional counter is recommended here.

To record consumption (and generation), Modbus-capable intermediate meters must be installed:
Either you install an intermediate meter for each consumer and generator or you install a central meter on the house connection. In both cases, the cFos Charging Manager reads the meters via Modbus (we recommend the ABB B23 112-100 with direct measurement for outputs up to 40kW and the ABB B24 112-100 with transformer measurement with appropriate transformer coils for higher outputs. Both can be easily configured via Modbus Read out RTU. However, the cFos Charging Manager also supports many other meters, see table " Which meter can do what? ".

Many intermediate meters output so-called S0 pulses (e.g. 1000 pulses per kWh). The cFos Charging Manager can also evaluate these pulses per counter using a USB FTDI adapter

By recording consumption and generation, the cFos Charging Manager always knows how much charging power to distribute to the EVSEs in use. You can assign different priorities to the individual EVSEs. The available charging power is first distributed to the EVSEs of higher priority and the remaining power is then distributed to the EVSEs of lower priority. This way you can, for example, quickly recharge emergency vehicles while long parked users are "refuelled" during the day

The prioritization scheme also supports the temporary shutdown of wall boxes if the minimum charging power is not reached. In addition, there is a monitoring of the phase symmetry to prevent individual phases from being loaded beyond the level prescribed by the VDE during single-phase charging.

Charging rules

Using charging rules, load management can be configured for each user and for each wallbox, several charging rules can be configured, which determine the charging power according to specific criteria. You can use this to configure certain times, for example, when the charging power is limited.

In addition, the charging power can be changed depending on a switching input, for example when the energy supplier signals certain tariffs. Another possibility is to control the charging power depending on the available generation power of a solar system (e.g. by excess charging).

Material list

  • Wall boxes and cabling
  • 1 Raspberry PI 3 or 4 plus power supply unit or Windows PC
  • One USB <-> RS485 adapter (FTDI, virtual COM port) per Modbus RTU
  • Intermediate counter
  • Additional FTDI adapters for S0 counters
  • additional RFID readers for cFos Charging Manager (may require additional Raspberry PI)

It is recommended that the cFos Charging Manager is connected to the Internet and can be accessed from "outside" for maintenance purposes.

cFos Charging Manager prices

  • License per charging point: From 94.01 euros (incl. 19% VAT)

Detailed price list for the cFos Charging Manager and hardware kits

System requirements

  • Windows 10 or Raspberry Pi 3 or 4.
  • Recommended: Internet connection for automatic setting of the time, software updates and access for remote maintenance. If there is no landline connection, you can also use an LTE router with a SIM card.

Details for the network operator

Manufacturer / TypecFos eMobility / cFos Power Brain 11kW (22kW)
Number of charging pointsDepending on how many EVSEs you use - one charging point per EVSE
Number of identical charging devicesDepending on how many EVSEs you use
Max. grid demand power in kVA11 kVA or 22kVA
Max. grid feed-in power in kVA0 kVA
Control range of charging power kVA to kVA6 kVA - 22kVA
Active power controllable (yes / no)Yes
Type of charge (AC or DC)AC
Alternating current or three-phase currentAC for 1-phase connection, three-phase for 3-phase connection (controlled by the car's charging equipment)

Manufacturer's declaration

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