Re: Where To Locate a Solar Panel?
Reply #27 –
My flex panels (unisolar) are not as long as yours but only 60-watts (@12vdc). They are much less prone to shadow problems due to the way they're wired. I should have bought a third one to use on my 21' Streamline (fishing trip) trailer; just have two 30-watt hard panels for that. You can see the fishing trailer with the little 30-watters in use at Adventures in Paddling the Pacific Northwest. Advantages to the little panels is that I can move them around as the earth rotates to keep them aimed at the sun. Those panels gave us enough power for TV, radio and lights for a week's vacation camping in So. Cal. (before we got the FT).
You don't actually HAVE to have a charge controller, either; as long as you perform that function yourself. And if you use a germanium diode instead of a silicon diode you won't have that 0.6volt drop; but germanium diodes of sufficient current capacity are hard to find. Ebay is probably the only hope. I had one on our sailboat in the 1980s and it worked beautifully.
On the trailer I just connect the panels directly to the battery (they have built-in diodes) and use a digital voltmeter to determine when they need to be disconnected (once the batteries reach about 14.5vdc). You could do this with larger panels if you were careful but I'd worry about wind throwing bigger panels around but if you don't want to mount the panels on the roof top it's certainly do-able. I wouldn't get anything larger than the panels John Haygarth is using and I'd figure out a decent way to secure them.
Craig
Topic: Where To Locate a Solar Panel?