Off-grid-enabled storage system for self-consumption increase in Freiburg

Project Info

  • Construction Date

    October 2014

  • Category


This object is a house in Freiburg with 3 separate apartments. The investment was made by the owners’ association. The client’s desire was to integrate the existing PV system with grid feed inverters in an off-grid-enabled storage system for self-consumption increase. The customer has placed great emphasis on ensuring that in future no energy is fed back into the grid and a grid autonomous operation is possible when needed. For this reason, the existing feed-in inverters (Sunny Boy 5000TL and Sunny Boy 1200) were replaced by a Studer VarioTrack 65 and a Studer VarioString 120. Together with the Xtender, the charge controller is operated in the DC-Priority mode and provides optimal operation in parallel to the public grid. By 2 MPP-trackers and the high input voltages of the VS-120, the existing PV generator 1 could be connected directly to the VarioString without changing the stringing. Only 2 additional branch connectors were attached to the PV generator 2, not to exceed the max. input voltage of the VT65 of 150V.