Solar panels for auger southern observatory: “SPIDERSHADOWS”

During the winter of 2009, technicians of the Pierre Auger Observatory (PAO) inform about how during a visual inspection they detect failures in the surface of different solar panels. The inspection was not casual, but due to problems with the level of charge of the batteries. Because of the aspect of the failure, we will name it “spiders” (arañitas). Other anomalies, related to the expected ageing, have been also observed: panels with blued cells, browed surface and others. In the present paper, we will describe each of the observed failures, their possible causes and their effect on the solar panel operation. The full data sample we used has been obtained either on dedicated laboratory test or by direct measurement in the field.