A high level tank at Rohrdorf/Meßkirch in the Swabian Alps, is used to supply drinking water to surrounding communities. The tank itself is located in an outside section and thus not connected to the public grid. To control the water distribution and to secure the operation of the system, a continuous and autonomous power supply of 24 V DC over the year is an indispensable requirement.

To cope with this requirement, 10 solar modules, each 180Wp/24V, have been mounted on the roof of the service building, totalling 1.8 kWp, and supplemented by one wind turbine, Ampair 600/24V, with charge controller. For the energy storage, a battery bank consisting of 4 Gel batteries with a total of 460 Ah at 24 V has been used. For easy and quick installation at site, all electronics have been pre-wired on an installation board and tested before dispatch. Thus only the cableing of the battery bank, the wind turbine and the solar modules had to be performed.