Solar Basics is a video series by Solar Power World created to help installers learn about the business, tools and tricks of the solar power trade.
Rule number one: Never use soap to clean a dirty rooftop solar project. Learn how to clean solar arrays while avoiding filmy residue that can impact energy production in this Solar Basics video, based on the story: Pro tip: Never use soap to clean dirty solar panels.
Firewood Greeley Co says
Absolutely! you need a good-quality soft brush and a squeegee with a plastic blade on one side, and a cloth-covered sponge on the other, with a long extension arm.
Solarman says
Way back in 2005 it was Sanyo that recommended and (specified) dish washing liquid and specifically stated, not the kind that has additives that are “gentle on your hands.”
Now vinegar and hydrogen peroxide sounds pretty good. Harsh chemicals could also dry out the seal around the panel and cause moisture entrainment. I found in my particular area, once or twice a year was plenty and a final rinse with water and a soft rubber squeegee kept the panels producing over the years. The problem I did find is there are some bugs that like to lay their egg sacks right on the panels. These don’t easily wash off or squeegee off and leave a waxy shadow on the panels. The surfactant of a soap, seems to work well on these waxy leavings, often use of vinegar might effect older panels with light catching coatings to enhance light capture.
Semper Solaris says
Great points, but I’m always nervous when it comes to harsh chemicals on the solar panels as like you stated, it can cause moisture entrainment. I usually recommend to customers that a hose and brush is the easier way to go as soapy water does leave residue, but sometimes the extra dirty panels need some additional TLC.
Bugs are another issue like you stated so depending on how dirty or what the issue may be, there are different cleaning strategies for solar panels.