I haven't been using the trailer much this summer but did notice that things (beer)weren't staying cool while in the fridge as the trailer sat in my driveway. Freezer compartment was OK. As I have a short trip coming up I figured it was about time to get around to it and add a fan or two to help keep things cool. I knew about this trick and your recent enquiry prompted me to get going on the project.
Following this guys advice
I added an inexpensive computer fan ($1.00) fan in the outside compartment yesterday. I simply tapped into the existing 12 volt wiring that was feeding the
refrigerator, wedged the fan in, pointing up to blow air over the coils and out the top.. Temperature here hit 30C (85F) and the trailer was sitting in the direct sun most of the day.
The improvement in the performance of the fridge was very noticable as the beverages were cold when I got home at 7pm. I will make the installation permanent with the addition of a rocker switch and/or some type of thermostat control. I am now either going to look for a fan for the interior or see if I can wire something up directly to my
battery.
The fans I am using draw 0.25 amps which my system can handle as the
solar array is constantly recharging. If you are not constantly charging your
battery then you need to take this constant draw into consideration.