Solar based self-sufficient smart sensor nodes are broadly used for remote monitoring purpose especially for applications, where the assessment for human is hostile. For the power supply of these smart sensor nodes, solar panels and battery are usually used. In order to collect the solar energy more efficiently, the solar penal of the sensor node should be directed optimal. In this paper a study at Schnarrenberg with the coordinate [48.8°, 9.2°] in Germany has been done, to determine the optimal tilt and orientation angle, which maximize the received solar energy at an inclination in the worse months, nevertheless without weakening of the solar energy of other months. Finally, with the calculated average monthly solar energy on this inclination, the minimum value was taken to determine the peak sun hours to size of the solar panel. Our approach is evaluated by applying the hourly solar global and diffuse irradiance on the horizontal surface from the open metadata of the German Weather Service, between 2013 and 2017. The evaluation results can be used for distributing sensor nodes along high voltage overhead lines in the framework of PrognoNetz research project.