Larry: This is a new install, and it's not 'on-line' as of yet.
With the angle mount, mother nature should help.
Another job (rooftop) nearby has a 'bird' issue with gulls from an abandoned landfill, and another landfill accross the river. They have a maint guy do a hose down about every 2 weeks, and a contractor to low pressure washdown quarterly, or more often if needed.
Perhaps, this could be the start of a new cottage industry? Like 'Harrys Panel Wash'?