A solar panel cleaning brush assembly including a trolley frame having parallel first and second side frame members. A first guide member is connected to the first side frame member. A second guide member is connected to the second side frame member. A first belt rotatably disposed about a perimeter of the first guide member directly contacts a first array edge of a solar panel array. A second belt rotatably disposed about a perimeter of the second guide member directly contacts a second array edge of the solar panel array. At least one brush set is connected to the trolley frame, the at least one brush set having multiple fixed, non-rotating brushes each frictionally contacting and spanning across a module face of individual ones of multiple solar panel modules defining a solar panel array.