Yeah John I messed with mine over about 600 hours just trying to find out the best "Target" temps to aim for also there are 2 ways of packing a fridge, One has a longer duty cycle than the other but the longer cycle can use more power, bottom lines is these 4x4 fridges are way better than any domestic fridge you can buy, regardless of the cost of either unit,
I'm trying to wrap my head around putting a fan inside. I suppose the obvious question would be the goal, is it to have an even temperature inside or to minimize cycling. If you agitate the air that's going to assist any heat transfer, which you may or may not be what you want. Usually the goal is to disturb the air inside the fridge as little as possible, since you want it to settle to the bottom and stay there. If you pack items that need to be coldest at the bottom and warmer stuff on top, then the fridge won't have to run as much to keep that temperature gradient.
I put a micro cooling fan in the back of my fridge facing back behind the cooling plate this was a MAJOR improvement keeping a uniform temp through out the fridge. It has a very low air flow, you can hardly feel it if you put your finger in front of it , but enough to keep the air circulated. I stuck it up in the corner on a piece of foam and 2 sided gorilla tape not wanting to drill holes. I also put a larger cooling fan on the compressor which also really helped lowering the heat transfer into the interior. Then I put a remote temp gauge inside the interior so I can accurately dial in the specific temp I want eliminating the guesswork of the exact interior temp. I ran the wires for the temp sensor and fan wire up through the drain pan tube so I wouldnt have to drill. These mods uped my efficiency 20-30% saving battery use. The reason for the high temp in pix just turned it on to take the pix. The switches are for Interior fan, temp gauge and compressor fan
I see that putting a fan down near the motor could help but putting a fan on the inside limits the correct storage for many foods, A fridge is not just a cold place to store food, Many foods require being stored at different temperatures which is why the Element in the ARB's does not go to the top of the inner walls because by doing that it creates at leased 4 different temperature zones, Fitting an inner fan creates just one temperature zone so what you end up with is foods that need to be cold end up either too cold or not warn enough and foods that need to be warmish end up too cold. Which in theory means you can only store one type of food, That works ok for a Freezer but not a fridge,
If fitting an internal fan was a good Idea then ARB, Engel, National Luna and Waeco would of done it years ago, The only time fridges are fitted with an internal fan is when one type of produce is needed to be kept at a certain temperature, Or when a domsetic fridge is supplied with a motor/compressor than is not man enough for the job, Having a fan in a domestic fridge again is more of a design flaw and should really be avoided, A fridge should have an internal temp range that varies from zone to zone/area to area by as much as 10*c/18*f and not by 2 or 3 degrees C*/F*.
Because many food types require different storage temperatures does not make it practical for fridges to be fitted with fans because you would need a separate fridge for every type of food that needed to be stored, Which is another good reason why fridges are made the way they are.