GP Joule

Charging park with intelligent load management

Customer profile

Turn your own problem into a solution – GP Joule entered the electromobility market with this motto in 2015. Needs-based solutions were scarce, and so companies were becoming providers of e-mobility and charging infrastructure themselves – almost on a green field basis – with expert partners. GP Joule Connect has worked closely with Phoenix Contact E-Mobility GmbH since 2015.

Jonas Elbroend (left), Hardware Product Development, and Piet Gömpel, Software Product Development at GP Joule in Reußenköge, Germany

Jonas Elbroend (left), Hardware Product Development, and Piet Gömpel, Software Product Development at GP Joule in Reußenköge, Germany


The basic element of a new charging park is always the charging station. “Deficiencies, for example in terms of stability, user convenience, energy efficiency, and mains connection, are difficult to fix after the fact,” says Jonas Elbroend, based on his own experience as a hardware product developer at GP Joule Connect. “The built-in charging controller needs to control the current during the charging process, and also needs to be able to be controlled from a higher-level system.” Furthermore, the charging controller should be flexible so that different charging modes can be selected.

Other charging functions on the wish list included a 6 mA DC fault detection system and a 30 mA residual current device to protect the charging points and to switch the load. For charging mode 3, case B with charging socket, a voltage monitoring function should also be included in the charging controller for unlocking the charging connector in the event of a power failure.

For the load management system to be implemented, the charging points should be distributed in rotation across the three line conductors. This ensures that the maximum unbalanced load – specified by the energy provider – is not exceeded. Given the circumstances, the hardware and software must also be perfectly harmonized.

Charging controller

The correct charging controller (lower two rows) is the basis for optimum load management


The question of how the charging park’s energy supply is ensured through the available connected load is of fundamental importance. “An energy management system is needed to control the charging park energy flow,” explains Elbroend. “This can either be autonomous – in other words, responsible for one charging park – or it can be part of a comprehensive building management system.” In an autonomous system, the available connected load is the only specified value for managing the charging park.

“The Ethernet-capable CHARX control advanced charging controllers and CHARX manage software from Phoenix Contact facilitate ideal energy management,” explains Piet Gömpel, software product developer at GP Joule Connect. “The controllers are managed by the software via Modbus TCP. It also manages approval for the charging process and regulates the charging current.”

One of 30 charging stations at GP Joule

GP Joule can extend the charging park successively as necessary

Charging park operators can either bill charging processes locally or using a billing system. GP Joule itself uses the software’s export function for billing and forwards the consumption data. In contrast, in the public sector, charging processes are usually billed by a back end provider. The backend provider receives the consumption data via OCPP – the protocol is an integral part of CHARX manage.

GP Joule now operates over 30 charging stations in Reußenköge and over 20 more at other locations. Extending the number of charging points is easy with the license model for 10, 30, or 50 charging points. “Our customers often start out with a basic installation with just a few charging points,“ says Gömpel. ”With an upgrade license, the system can be extended flexibly at any time with additional charging points.”

Administration in the office

With CHARX manage, employees have access to diagnostics information on the charging status and occupancy time

With CHARX manage, the parameters for the charging park, individual charging points, load management, and connection to the billing system are configured easily in a web-based interface. From any PC via a web browser. If, for example, the operator is logged in, relevant settings can be viewed or changed.

If a central terminal with touch PC and RFID reader is available to the electric vehicle driver to register, the charging point can be selected and the charging process started through an intuitive user interface. Alternatively, a box PC can be used and each charging point can be equipped with an RFID reader for user registration.


Using this approach, GP Joule Connect brought around 300 charging points into operation in 2019. To meet the demanding customer requirements regarding operation, energy management, and availability, functions for using cloud services are also implemented in the CHARX manage software.

As Jonas Elbroend says in summary, “CHARX manage from Phoenix Contact is tailored to companies that want to use between ten and several dozen charging points in the future and which have professional requirements for energy management, operation, and upgrade security.“

As Piet Gömpel adds, “With CHARX manage, our charging solutions can be used flexibly in different environments in charging parks. We can use it to offer our growing customer base a complete solution, from analysis, planning and implementation, all the way to operation.”

Kontakt (en)
Phoenix Contact India