Kölner Verkehrs-Betriebe/SBRS GmbH

Charged up in 60 minutes

Charging infrastructure is one of the major stumbling blocks as we switch to electric mobility. For example, if urban bus routes are changed to e-mobility, they will also need powerful charging stations. The Cologne Public Transport Authority (Kölner Verkehrs-Betriebe/KVB) shows how this could look at its northern depot. Also present: a VX25 enclosure system from Rittal.


Kölner Verkehsbetriebe/Cologne Public Transport Authority
Cologne, Germany

Powerful charging stations for about 100 e-busses in Cologne

Charging overnight in the bus depot

Charging via roof-mounted pantographs on the buses

System comprises 53 charging points with DC voltage

Maximum power of 150 kW

Demand for high stability of enclosure



Charging system by SBRS

Electrical engineering technology is installed inside Rittal enclsoures in a separate building

Due to high degree of efficiency and low level of loss, no active cooling necessary

One Rittal VX25 enclosure for each of the 53 charging points that contain power electronics, comntactors and automation technology for the chargung management



The KVB relies on electric buses. An efficient charging infrastructure is needed to operate a fleet of over 100 buses. The battery capacity – around ten times larger than a car’s – shows that charging e-buses is anything but a trivial task.

We never had any doubts about the quality of the new VX25, as we had good experiences with the previous model.
Markus Heine, Project Leader with SBRS GmbH

Having planned, built and launched the charging system for Cologne Public Transport Authority’s northern depot, the plant engineers of SBRS have demonstrated how efficient charging infrastructure of this kind can be realised. The fleet of buses is charged overnight, using only green electricity. The connection between the vehicle and the charging station is not made via plugs but through roof-mounted pantographs on the buses. The system, comprising 53 charging points, charges buses with DC voltage, delivering maximum power of 150 kW. 

At its heart is the highly efficient SBRS intelligent load and charging management system. “In principle, it’s possible to fully charge the buses within 60 minutes,” says Markus Heine, Project Leader at SBRS. “However, in normal operations, they’re charged over a period of three hours or so to achieve maximum efficiency.”

The electrical engineering technology is installed inside enclosures in a separate building. Thanks to the high degree of efficiency and therefore low levels of loss, no active cooling is needed for the enclosures. There is one VX25 enclosure each of the 53 charging points, and the power electronics, contactors and automation technology for the charging management are all installed inside these enclosures. With the components inside each charging point weighing over 400 kg, the stability of the enclosures used is crucial. The power semiconductors for the DC charging technology are modular in design. This means it’s easy to scale the charging capacity up or down in line with requirements. The enclosures have perforated doors on both the front and the back – and the only type of cooling that takes place is passive. The only fans fitted are for the power semiconductors.

The flexibility that the system offers in terms of expansion is another argument favouring the VX25. “What we get is a one-stop solution that includes everything from the enclosure and its installation components to the base and accessories such as a door switch,” emphasises Heine. Two other particular advantages that helped win over SBRS were the very quick availability of the enclosures and the modular system of the VX25, which means that fewer different components are needed.