Snail trails under the microscope

This beauty we found during one of our recent PID hunting expeditions. Looks like a rout of snails have had a game of football on this module.

Snail-trails are caused by air & moisture ingress through the back-sheet, and the usually through a micro-crack, causing the silver-nitrate compound in the grid fingers to bubble, bleed and/or discolour into the EVA encapsulation. The easiest visual phenomena to spot whilst walking around solar farms!

Under Electroluminescence this shows up as a severely cracked module and depending on the age of these cracks would determine how much power impact there would be. This is a particularly bad module however.

Almost like a piece of art ;o)

The question is, do snail trails and micro-cracks effect power output? The answer is yes! But in a large range of severities. The only real way to know is to conduct a lab-grade flash test to STC. But before that you need to know if the expense is justified, so a high-resolution quantitative aerial survey would be the way to go.

Happy snail-trail hunting ;o)