Back to the OP.  Yesterday with the fridge 1/2 full with water and beverages the temp during the daytime stabilized at 43-44 degrees which is better but the outside temp was cooler as well, only getting up to 88 degrees.  This morning at 6 am temp was sitting at 42 which didn't please me as outside temp was 74. 

Decided to clean combustion chamber yet once again in light of all this fussing.  Turned to electric, causing the fridge temp to drop from 43 to 36 degrees in about 3 hours.  Let combustion chamber sit in mineral spirits for 2 hours and then blew out with compressed air and re-inserted.  At noon I turned off the electric (fridge was at 37) and turned propane back on.  Here it is 3.25 hours later and the temp has not changed, outside temperature is 80.  So things are looking up at this point.  Trying to figure out if there may still have been some crud either inside the combustion chamber or inside the orifice - doesn't seem likely as both had been cleaned out 2 times before doing it again this morning.

I wasn't comparing 12V FPSC to propane Dometic, but 12V FPSC to Dometic on 12V. That is why I will continue to use the Dometic on propane when not connected to shore power or towing and use the FPSC to supplement for meats and other things that really do need to stay cold, even in hot weather.

You got a steal of a deal. Keep it nice, it might be a collector's item before too long. I don't think you can get a FPSC now, except for high end computer builders who spend big bucks to buy tiny ones to cool their overclocked CPUs to -40C or some such craziness. 

You can't compare the Dometic on 12V to the Danfoss, the Dometic absorption cycle COP is probably around 0.5 vs around 2 for the Danfoss (or FPSC). The absorption fridge is terribly inefficient but there is so much energy content in propane that it more than males up for it RV applications. 

IIRC (which I might not, it was 35 years ago) the Secop controllers provide low voltage square wave output to the hermetically sealed compressor motor. So they are a kind of inverter, just like brushes and commutator are a kind of inverter. That is what a brushless DC motor design does, it replaces the com and brushes with transistors do the polarity switching, based on a position sensor within the motor. You can't hermetically seal a brushed motor so this was the solution. The variable frequency 3 phase AC motor drive systems were originally developed for big industrial motors and have now made their way into EV's. But for a little bitty fridge compressor those are overkill, at least so far. 

Yeah, there are 12V positive and negative wires or terminals, but the windings of the compressor are something else. Otherwise, with typical 12V DC motors, we would need brushes and commutators, and these compressors do not normally have those.

Although, I have not torn into one to verify that.

At any rate, I did the typical solar powered fridge experiment most of last year...I found that to have more compromises than a propane powered fridge. Just sayin.

+1 to Podwerkz. I added a cooler similar to this one to the inside of mine:

I also had a couple of muffin fans from computers in the house and I added them to the outside top cover, set to blow out to help extract hot air from the rear compartment. between the two, my refrigerator seems to keep temperatures better provided I periodically clean the propane system. Still, on hot days, especially with the sun beating down, the temperature in the refrigerator will rise into the 40's or 50's, especially if the AC isn't running to help keep the inside of the 'Pod cool. The heat coming from all sides is just too much for an absorption refrigeration system to handle. It would probably need twice the insulation to be able to keep cool in 90+ degree temperatures.

OTOH, I was able to purchase a Free Piston Sterling Cooler which operates on 12V, either from an automobile style 12V plug directly or through a transformer for AC power use. This thing is able to keep right around 4C (about 39F) even in high 90's temperatures. It was used by drug companies for transportation of medications (no biologics or organs), and was donated to ReStore where I purchased it. Unfortunately, it is nearly impossible to find new ones at any sort of reasonable price. It is very efficient, and will not kill the battery overnight as it takes much less power to run. The newer Danfoss compressor refrigerators are also supposed to be efficient enough to use, but I have no experience with them.

The thermostat works similar to your fridge at home, the cooling unit runs longer, or maybe continuously, to cool the interior when you set the unit to a 'higher' setting, which is a cooler temp.

You might try moving the thermistor on the cooling plate, or adding one of those little battery powered RV fridge fans inside the fridge, or adding an extra 12v fan on the exterior condenser fins, all of these can help, but otherwise these units are not the most powerful fridges ever made. On the other hand they sip propane...extending our ability to stay 'out there'...

What I would tentatively conclude from that is that your gas and electric sides are both working about equally well, and obviously the fridge is cooling. Where I'm heading is I'm not sure there is anything wrong with it at this point. 95 is hot, it might not be able to maintain really cold temps is all. 

I think you're on the right track by adding more cold water/ice to the fridge. That will definitely help  stabilize things more. Water (or any kind of drink) has very high thermal mass (1 btu per lb per deg F to be precise, and 144 btu per lb to melt ice). If you put say cold canned drinks in there (compared say to a gallon jug) you will also have a lot of surface area to transfer heat between the water in the cans and the air in the fridge and that will help keep the afternoon temps in there lower. Try it and see, but as you say, put the liquids in cold and give it a couple of days to re-stabilize.   

Finally able to report back after a few days of testing.  Running electric I found fridge temp at 6 am 35-36 @ 6am going up to 48 - 50 during the hottest part of the day 2-4 pm where temp would rise to 48-49 degrees.  On the propane side fridge temp at 6 am would be 35-39 and at the hottest part of the day 2-4 pm temps would be 49-51.  This was done with a totally empty fridge with the exception of a pan of water placed in the freezer in the evening - each time under all circumstances ice would be made by morning.  Outside temperature during the hottest part of the day varied from 90 - 95 F.

My next test is to find out if these are normal operating temps with the existing outdoor temps and putting pre-cooled items (water and beverages) inside so that it isn't totally empty.  It will now be 50% filled with the above - will be interesting to see if this will allow the interior temps to be more stable during those hot parts of the day.

2 questions still emerge.  Are these temps that I give 'normal'?  Are these similar to what your temps are under somewhat similar conditions?

I have been told that the electric mixer valve may be faulty, that when I turn up the call for colder temps, (eg. - from 3 to 4 bars or 4 to 5 bars) that I should observe a larger flame which will produce more heat to cook the ammonia more vigorously giving me a colder temp.  When I went from 4 to 5 bars I did not observe a larger flame, it appeared to my eyes the same size.   Is that true, have you observed a larger flame when doing this?   Thanks for your patience, this has been quite a learning experience thus far.

Oh yeah...minor detail.

Well, at least my post may function as a public service announcement to folks who may not have realized how important a level RV is to fridge function...

If it got down to 37, then it is likely working well. The only way I know of to check the regulator is to do a pressure test. You could purchase one from Amazon or make one. The site linked below talks about making one. The actual instructions are linked within the page.

Edit: This is the link for how to build a manometer:

Thanks Stephen.  Never thought about a faulty regulator.  The one I have is the original from January 2011.  IF the regulator is bad wouldn't I see a problem running the burners on the stove or a lack of heat when the furnace runs?  Also is there any way to check or test the regulator to see if it is in proper working order?

Update on fridge temp.  This morning at 6:45 fridge temp got to 37, fantastic.  However now it is 10:30 am and it now reads 39.  However I also have a thermometer sitting a few inches from the refrigerator lower grill in the direct sunlight and it is reading 98 so hopefully that is why the temperature is rising.  In a couple hours the sun will be far enough south so the fridge side will be totally in the shade for the duration of the day.

One other thing that could be happening is that the pressure of the system might be low. If I recall correctly, the pressure should be 11" water column. I've seen instructions on how to make a tester. There is a small threaded port in the junction where the flexible hose ends that has a plug in it. That could be used to attach a tester.

You could try replacing your regulator and see if that makes a difference. They can go bad over time and not allow the proper pressure.

Originally posted by marwayne Jato, Cleaned up the fridge outside and turned it on, went from 23* C to 6* C in about 4 hours on LP

That was the good news as the next day the fridge temp went up to 57 during the daytime with outside temperature at 95.  Fridge was in the shade, facing north.  Had my son with grandkids up for the weekend.  He had to show off his new 25' speedboat so we spent most of the weekend tooling around on Torch Lake, plenty to see on a lake that is over 19 miles long. 

Now that they left I can get back to business.  I took off propane lines and blew them out from the regulator to the combustion chamber.  Let the combustion chamber part sit in mineral spirits for 20 minutes and blew out with compressed air.  Then did another stint with WD 40 soaking it well, letting it sit for 10 minutes and then blew that out.  Assembled everything and fired up about 1 hour ago.  Outside temp is 84, fridge temp has dropped from 86 to 83.  Will see if anything improves after all this fussing, which I rather do than purchase a new fridge!