Fast Charging Study case

Samsø is an island 15 kilometers off the Jutland peninsula in Denmark, and its community has been pioneering the green energy transition for more than 20 years.

In 2007, the people of Samsø were able to declare their island 100% energy self-sufficient with wind, solar and biomass energy, an achievement that was largely due to widespread support and investment. Samsø Energy Academy’s ambition is to offer a broader sustainable perspective based on the UN’s 17 Sustainable Development Goals. One of the key projects at the moment is to make Samsø completely independent of fossil fuels by 2030. This project includes targets to reduce local electricity and heat consumption and for all transportation on, to and from the island to run on electricity or biofuel as propellants.

We at FLEXeCHARGE are proud to contribute to the green energy transition of Samsø with our intelligent Load Management solution for an EV fleet of an ambulant nursing center. In total, six charging stations have been equipped with the FLEXeCHARGE Decentral Load Manager. In collaboration with the Center for Industrial Electronics (CIE) at the University of Southern Denmark (SDU), the charging station use patterns and charge profiles have been analyzed for the charging infrastructure with and without Load Management. After the first months, the results were already very promising, with an average reduction of charging times of over 30%. This reduction was possible thanks to the different features provided by the Load Manager, which work together to obtain the most efficient charge possible. First of all, let’s mention the clustering function.


Charging points that are part of a local area network can be separated into independent load management clusters that act entirely independently. For each cluster, a maximum current can be defined, and the available charge power is allocated without considering the state of other clusters. Clustering can be used for situations where the charging currents for a specific number of charging points must be limited or when all charging stations are connected to the same LAN but have different power supply topologies.

Samso ev charging

Let’s take a look at the graph below. In this case, the charging infrastructure is composed of four charging stations sharing a main power supply. The maximum current limit of the main supply is limited to 50A, either by a soft limit due to other consumers or due to a maximum current rating of a supply component. This means that the 50A threshold should never be exceeded for the entire charging infrastructure.

CLUSTERING samso fast charging

 The main power supply is divided into two power cables, each of which feeds two charging stations. The maximum current of the charging station power cable is 32A. This allows each charging station to theoretically supply 32A if a single electric vehicle is charging and 16A if two vehicles are charging. All charging stations are connected to a LAN with Ethernet, WIFI, or a Powerline Communication (PLC).

In a scenario where load management is not present, one would need to hardcode the maximum limit per charging station to 50A divided by 4, which results in a maximum charge current of 12.5A for each station, no matter how many EVs are connected.

When using the FLEXeCHARGE Load Manager, two clusters can be defined with a maximum limit of 25A. This means that the charging current is doubled if only one of the stations in one of the clusters is occupied. This halves the charging time for connected electric vehicles compared to an infrastructure without load management.

Done Charging

Through a recent update, we deployed the Done Charging feature that detects when the EVs are fully charged and automatically reallocates the charging currents. Our customer is now enjoying an average charging time reduction of over 56%

If an EV, which is in the Done Charging state, requires to return to the charging state, the Decentral Load Manager has a build-in Done Charging Duration after which it offers the EV to continue charging. By default, the Done Charging Duration parameter is set to 15 minutes. This means that an EV that is in the Done-Charging state gets the opportunity to continue charging every 15 minutes.

Our customer is now enjoying an average charging time reduction of over 56%

📍 EV fleet at Tranebjerg, Samsø 

Reduced charging times increase the utility of the EVs and provide the foundation to further increase the number of charge points without costly grid extensions.