By Greg Illes
A lot of us have seen the after-market circulation fans for RV refrigerators. They are small, battery-powered units that purport to help keep the inside of a fridge at uniform temperature.
The premise is accurate and air circulation provides several benefits such as even temps, reduced humidity, less ice and so forth. But, unfortunately, the after-market products leave a lot to be desired. They require periodic battery replacement, which most of us can manage (maybe) — but they also provide very little air, have a high failure rate, take up shelf space, and are in general very poorly reviewed.
Taking all this into consideration, I decided on a permanent fan installation. My requirements were simple: reliability, decent air flow and very low current consumption. A brief survey of digikey.com turned up a 12V ball-bearing fan that pushed out adequate air and needed only 25 milliamps (that’s 0.025A) of current. Even running full-time, it takes this fan 160 hours (almost a week) to use up 2% of my coach battery capacity — essentially a non-consumer.
Mounting the fan took only a simple piece of aluminum bent to a shallow angle, and two sheet metal screws to fasten it to the sturdy inside wall of the fridge. Getting 12V power to it required removing the fridge control panel (two screws for a Norcold fridge), finding the 12V line which powers up with the fridge ON switch, and using a simple wire-tap splice. Another one for the ground lead, and we were merrily spinning the fan whenever the fridge was switched on.
For this prototype installation, I covered the wires with white duct tape (shown), but after a trial run I will drill some holes so the wires don’t have to route past the door seal. It works fine either way, but it will be just a little “cleaner” with the wires hidden.
I have a week’s time operating it now and I can easily see the differences. The cooling fins stay frost-free, and all the items and areas in the fridge are equally cool. It also really helps a lot when new items are put in the fridge — they get down to temperature more quickly now. The days of cold cheese and warm beer are finally over.Here are the particulars on the Digikey fan:
Digikey part 381-2500-ND
Volume 19.4 CFM
Power 0.3W (25mA at 12V)
photo: Greg Illes
Greg Illes is a retired systems engineer who loves thinking up RV upgrades and modifications. When he’s not working on his motorhome, he’s traveling in it. You can follow his blog at www.divver-city.com/blog.