We had been talking before about solar power, and this past long weekend I finally had a chance to put my solar panel to the test. We were dry camping for 4 days; which would normally either cause a great deal of strain on the battery, or we would have really had to ration power.
The solar panel I have is this one:
Coleman 40 Watt panel
Where we were camping we had morning sun, and then shade by 3:00. That meant shade for a full hour of the peak sun. However I did find that there was still significant power coming from the panel in the shade. I didn't have my good power meter with me; my judging of power use was based on how low the power dropped when using things like the water pump.
I had also unplugged the solar panel at 4:00 the day before we were leaving, and then didn't plug it back in until noon the next day when it looked like we might be staying an extra day. (Losing the morning sun charging I had the pervious days.) We still pulled out of the campground with 12.3 volts showing on the battery; my battery is "full" at 12.55 volts. And yes, that 12.3 volt measurement was taken an hour after taking the panel off; so it isn't artificially high.
For this to work, you have to also keep in mind that I have LED lights. As I always say, the LED bulbs are the first step in conserving power when dry camping. The one thing that was a massive power draw for us was the water pump. As we were camping by the beach and I was the only person in the group with a trailer, the outdoor shower got a workout. We had to refill the fresh water tank, and didn't come close to capacity on the waste tanks. So easily 75 gallons of water pumped through; which is a huge power draw. We also had quite a few lights on, and we even leave on light going all night. We also had the TV and BD player running for about 3 hours per night; once again both of those drawing 12 volt power from the battery.
So the solar panel worked well. A buddy had lent me his 1000 watt Honda generator, but I'm glad I didn't bother bringing it.