They are just bypass diodes. They are supposed to help during partial shading. Mine do not have that problem. If you check back my panels put out 600 watts in full sun. Now they only hit 200-225 watts in full sun. I was looking at the fronts of the panels and now have a discoloration. On some of the cells. Also I still have them in series parallel. So cells are damaged. When I have time I will check each panel in full sun. Post results when I can.