My solar modules are completely clean and dry all the time. When I installed the solarud units, I thought that after a rain shower the water would slowly rinse down the solarud modules but I found that it constantly rinses down and immediately after the shower there is only a thin film of water on the modules that dries very quickly. There is no water on the modules ever. Before I had a rim of dirt about 15cm wide on each module, since I have the solarud units installed, Nothing anymore. This is how it looked before, the darker areas show water still standing on the modules after a rain shower some time before: