by LazyJones » Mon Jul 14, 2008 4:05 pm
Hello,
I am in the solar business and you are all correct in many ways. The best way to deal with camping in the shade is to drag a solar module out into the sun. Unfortunately, sometimes they will "walk off" if you leave them out while running down to the store or going fishing. If your trailer is in the sun when it is not camping, the best bet is to put the solar on permanently, and then use a larger battery bank. However, this also adds more weight to your little rig while towing.
Flexible solar modules are about as efficient ( power output per area ) as the thin film Chinese stuff at Harbour Freight. Regular solar modules with standard silicon cells will put out the most amount of power per square foot and they tend to be more rugged than the Harbour Freight variety.
When you put a solar module in the shade, you can measure a little bit of voltage, but very very little current. Current is what you are trying to push into your battery by having more voltage in the solar module than the battery voltage.
Line loss will be very low if you use a 10 or 12 Ga wire in your two wire 50 foot extension cord. Most modules are producing power at a higher voltage than your battery wants anyway. The line loss is usually measured in voltage loss, so if you lose 1/2 to 1 volt out of a 16.5 volt module, no problem.
Hope this helps a bit.
Gary, solar guy
