whats your thoughts on keeping solar panels clean will it make a difference? I'm in two minds to give them a wipe down...I'm making 10 amps with the wind Gen going as well. It's not all that silent wind!
I measured the output amps from 420W of solar panels on a caravan before and after cleaning. Skies were mostly clear and in full sun. I think I was getting about 9 amps before cleaning. There was plenty of accumulated dust on the panels. After a good clean I got...... 9 amps! So I was very surprised. Unless there is so much dirt that the panel is "shaded" then I don't believe the difference is worth the effort. I'll just let the rain clean them from time to time.
Common Sense would indicate to clean them. 
As the angle of the dangle increases, performance will drop off faster. Solar panels are rated for full output at 1000 w/m2. And you can actually get more w/m2 than this on a nice sunny day. So if you do a test on a nice sunny day, you may have 1100 w/m2 to burn through the crud on your panels resulting in the rated output being achieved, and after you clean the panels, you will still be getting about the same output. But as the angle of the sun increase and you still have the crud on your panels, their performance will drop away faster.
Maybe do your dirty/clean test at 4pm and see if there's any improvement.
Well, I could be wrong again as usual, (oh that's right "Useless answer") but I'll be cleaning my panels.
A lot of dirt can make a difference. Before I mounted my 80W panel properly it was lying in the cockpit. If the boat swung so that the boom shadow feel on it the power out dropped noticeably. Cant remember exactly how much, might have been around 10%.
I believe one of the problems with solar panels is their ineffectiveness as the temperature gets above about 27 degrees. Keeping them clean is suggested for home solar panels and this probably keeps them shiny and reflects heat.
In addition to improving efficiency, cleaning also removes salt crystals. Salt crystals are nasty, as they act as magnifying classes. Intensive heat can not only degrade the panels, but conversion efficiency decreases with high temperatures.
