Solar-powered circulation fan

The first idea I had was to purchase and place a small game camera behind the small round glass.  I talked my self out of that because of the cost.  I stumbled across an old 6" DC fan I used to use for my hoop house.  I used an old solar panel to power it, and it worked really well.  In this case I plan to use a smaller 4" DC fan that will be wired into the solar combiner box.  When the sun is out it will use a small amount of power to move the fan.  My thoughts are this will help cool the trailer in the summer.  I know by changing the color from white to khaki it will also change the amount of heat generated.  In the winter time the fan will help dry out the inside and hopefully keep my gear from getting to musty smelling.