3 way frig. vs. 2 way

[Funstini]

I guess I'm just the opposite of what it seems everyone else is doing. I had a 3 way frig. loved it, used propane every time I used the camper. With the first frig. I got about 5 years out of it, second frig. not so much. Each time I lost my refrigerant, had a tendency to take the camper on some pretty bad roads and my thinking was it was the vibration and the rocking that got the frig. and coolant. Meantime I pull a Jeep to take on those nasty roads, and just make camp at a lower elevation. I thought a 2 way Dometic was the way to go. Up graded my (2) 6 volt deep cycle batteries to Lifeline's with a 180 watt solar unit. I do use a dish tuner and TV at night, but ended up using my Honda generator a couple times at night just so the batteries would not go lower that 12.4. I hated it ..... never enough battery power at night to maintain a good charge in the morning. I dry camp for weeks at a time, but hate firing up the rig and the generator on a day to day bases. I have noticed the Dometic is a power hog and maybe the Isotherm has a lower draw. But I guess I'm saying ..... I miss my 3 way. Each to their own.

Funstini

 

[RC Pilot Jim]

Hi Fun,

Compressor fridges are more expensive because you need 2 batteries, plus at least 150 watt solar on the roof, Definite plus for the 3-way

2-ways Will run 30* off level.vs 3-way has to be level. Will cool 95* below ambient temp vs 40* 3-way. I can turn my portable Engel on at Lake Havasu, AZ in June when the temp is 110*. and the camper is closed up. Come back in 30 minutes - temp 39* and it will hold that temp as long as the battery lasts. Engel cycles at 1.5 amp draw in 80* temps.

Isotherms are supposed to draw 3-4 amps when cycling NOT 5 like the Dometics do.

Edit
3-ways run 50 degrees below ambient temp. They are not efficient above 90 degrees.

 

[cwdtmmrs]

Jim, it just isn't true about a properly installed 3-way only holding 40* below ambient. You do have to adjust the temp control at night and during the day though.

cwd

 

[RC Pilot Jim]

Thanks for your input CWD.

Great that you are the exception to my and others experience. What year is your camper? What make your Fridge? What part of the country do you live in? All these comments on WTW are from everyone's experience. Perhaps the new ones are more efficient than the older ones. Or the efficiency gets worse over time. Or not keeping it level have caused cooling issues over time.

I was commenting on my experience of a 3-way from the 90's when we had our Lance camper, and many comments from others on WTW who have been switching to compressor because they are complaning that the absorbtion units wont cool below 40* of ambient temp.

My experience I tried to stay camping in outside temps below 85 degrees (in part because I had NO A/C). Park in the shade, Keep fridge side in the shade. Place two fans in the heater box. Place a small fan inside (to cut down on condensation). Have to keep it level. When we towed the boat to Needles, CA in April and May (temps 90-100*) we didn't experience the condensation issues...Just the trouble keeping the fridge temp around 41-42*.. We used a drink cooler and minimized the times opening the door especially since the "cold falls out when you do open it".

Our Engle portable compressor top loader has none of the down sides of Absorption (3-ways).

Four Wheel Camper through Tom previous owner (retired end 2016) produced an excellent video "Gallery" on different parts of a Four Wheel camper. As an aside I never knew "ATC" existed until two months before we bought the Eagle. My opinion was influenced by the various videos I was constantly viewing as I went through the decision process. Tom did "Refrigerator choices and Functions" This link takes you to their video library. Scroll down the the refrigerator section.

I reviewed it and Tom quotes an about 50* efficiency below ambient temp. "The Dometic Guy" says they are not efficient ABOVE 90 degrees. Makes sense because food will spoil if temp is higher than 39-40 degrees..

Doing a little research through Google I found the Following article : "camping friges there not all the same" And this one from
"The Dometic Guy"

 

[Funstini]

Yeah, I had no problems with my Norcold 3 way (other than losing refrigerant) and I was in some pretty hot places in the southwest. Always kept my food around 40 degrees. I long for the good old days, thought things were supposed to get better. I have never watched my batteries as much as I have lately, I just don't want to have to worry about them. Thanks.

 

[Bill D]

I enjoy my 3 way fridge as well. Turn on propane, turn on fridge, set to auto or gas. I usually have it set on setting 4/5 and I find things are nice and chilly. On setting 5/5 things can start to freeze.

I don't need a inclinometer, thermometer, or a physics degree to know it works well for me. I'm usually never in temps above 30C/86F

I personally wouldn't want to run on AC or DC. Propane is a much simpler solution for me. No need to add extra solar panels, a trimetric etc. At $4 per bottle of propane I could run the fridge for 50 summer camping seasons and it would still be cheaper than adding additional solar power and an extra battery (which has a high consumable cost).

 

[cwdtmmrs]

Jim, My camper is circa 1995 with the original Dometic Rm2193 1.9 cf 3-way. I live in SoCal (Inland Empire). You wouldn't catch me camping above 70* nighttime temps. Level to 1/2 bubble sideways or lengthways is fine. My fridge did not work well either until I completely reworked the installation for proper air flow and venting.. FWC's installation is terrible. My fridge will now easily keep 40* on propane when it is 100* outside. The surprising thing is how well mine works now on DC when traveling. On trips to Bishop up 395 it will keep 36*-38* on DC no matter what the ambient temp, and it has been 110* or better in Kramer Jct when I stop at the Pilot. I have a digital thermometer that records high/low and current temps, so I am not just guessing on the performance. I just don't want the extra weight and hassle of solar and extra battery. As Funstini stated, Each to their own.

cwd

 

[RC Pilot Jim]

CDW,

When you did your rework do you have any pictures or notes on the process? I'm sure there are others out there that would be interested in learning how you made your 3-way so efficient.?

Four Wheels 3-way install:
Back-in-the day the story was 3-ways mounted in pop up campers were difficult to cool. Our Lance was a 1977 with icebox converted by Lance to a Norcold 5 cubic foot 3 way in 1987 (we bought it used in 1986). The hard side campers have a chimney that extends to the roof. They are more efficient than the popups.

 

[cwdtmmrs]

Jim, this discussion comes up every couple of years and a search should bring up quite a few results. I almost never document my projects, but I did start with the improvements that "Roger" posted in Aug 2011, "Fridge fan exhaust" and went from there. I also got a few tips from one of the gentlemen that works at American RV in Azusa Ca. who said one of his former jobs was refrigerator installations for another RV company. Absolutely true about a pop up trying to exhaust out the side vs. a hard side through the roof in terms of efficiency. BTW, I have 2 Coleman "Survivor" (made by Dometic) 32 qt portable 3-way ice chests that I use when tent camping. They have little ice cube trays and have made ice in any temps.

cwd

 

[Ramblinman]

I think the 3 Way fridges are underrated. Because FWC/ATC is built in SoCal many owners camp in very hot weather in that area. I do not experience really hot weather - even in Baja cause I go in Jan/Feb. I camp a lot in Western Canada - read frequent cloud and rain - negating some of the solar viability. Readers should beware and take in to account who is offering their experience and where they live and the environment they operate in may be different than yours.

My 3 Way is a 2010 and works great - with out the added power draw and all the doo dads that go with it. And I save a couple of $$$$ for other projects or gas by not adding the expense of the electric fridge, batteries, panels, controller. In the hottest weather I supplement the fridge with a frozen water bottle from the freezer the night before - works for me.

 

[Funstini]

Apparently the Dometic RM 2354, 3 way is now a RM 2354 RB1F, has something to do with the cooling of the unit, and they have added 1 or 2 fans to help with the cooling. I will call the manufacturer tomorrow and get a update. I'll pass it on.

Funstini

 

[cwdtmmrs]

Funstini. I just re-read your original post and have to agree with you about power management with all the "stuff" that the camper's electrical system must supply. I have LED lights, a water pump and a furnace that I only run long enough to get the camper comfortable and then switch to my Wave 3 heater. I have a 9 year old 55 AH Optima yellow top that I have not once check the SOC and have never run out of electricity. I do drive the truck almost everyday and the 120 amp alternator manages to do the job. KISS. That's just me

cwd

 

[Funstini]

Called Dometic this morning and got the information. Apparently the RM 2354 is the newest model of a 3 way, and the RB1F is just the trim, ..... rt. hinge, black panel, 1 (don't remember but nothing ground breaking) and the F is for a fan. She didn't say if the fan was for a hook up or if it had the fan installed, but was planning on remodeling the fan cooling anyway.

Funstini

 

[TDFuego]

CWD

Your comment "how well mine works on DC.." is interesting. I have the same RM2193, yet it drains my house battery while driving in less than an hour. Unit is on an Eagle with gravity venting. Voltages all over 12V with Blue Sea Charging Relay in camper. Battery is Deep Cycle Interstate about 4 years old, but always kept charged (except when checking the 12v operation) even when parked. Have not load checked the battery, but all cells test ok. Resistance on the 115 watt heating element is within or at Dometic specs. Is there something I'm missing?

 

[cwdtmmrs]

TDF, I don't know. That question is better answered by the more electrical astute on the forum. I used to run the fridge on propane when traveling before the upgrades to the installation and electrical system. I would think that your alternator would be able to support the extra 10 amp draw on the house battery. My house battery is connected to the truck via # 4 and # 10 wires and a 100 amp constant duty relay to a 120 amp alternator that puts out 60+ amps @ idle. I have driven 12-14 hours without issue, but I do turn the fridge off if I am going to be stopped more than 15 minutes or so. The battery is 9 years old and mounted in the truck bed forward of the passenger wheel well. The battery load checked Ok when I had the camper off in Feb.

cwd

 

[TDFuego]

CWD, hey, thanks for the input. I have not checked my alternator, but it's rated at 120A. I've load tested the battery (it's okay), checked the heater element for proper resistance, and it checks okay. At idle I get 14DCV at the fuse box (this is after the controller), but I get 13DCV after I turn on the 12V fridge. One electrical expert suggests my alternator may not be putting out enough amps. Who knows? Thanks again for your input, I'm going to build a baffle for the gas, and go with that when on the road, what the hell, live dangerously! TDF

 

[cwdtmmrs]

TDF, It is easy enough to check how many amps your alternator is supplying with an amp meter. I think 14 volts might be a little low What gauge wires are you using to the alternator?

cwd

 

[TDFuego]

CWD: Okay, thanks agin on the amp advice. After fruitless efforts elsewhere, took truck to mechanic, alternator is failing. Anyway, my shop only had available 80 amp altornator.. I wanted at least a 100 amp unit. Do you have any advice on a brand? (I too long trusted the alternator okay based on voltage readings, big lesson here) Thanks for the help.

tdf

 

[cwdtmmrs]

TDF, that is kinda good news. At least it's fixable. I don't know what kind of truck you have, but high output alternators are available almost anywhere. I would put at least 120 amp unit in and maybe even higher depending on your truck's electrical needs. My 120 amp puts out a solid 60 amps @ idle. I bought it off eBay from a company called Ace Alternators in Whittier Ca. 877-903-4150. They have been there for years and are the actual rebuilders with real people to talk to. I think I paid under $120 with shipping. Hope this helps.

cwd

 

[TDFuego]

CWD, Yup, everything you told me has helped. I got a 140 amp off of ebay. Did it before I read this, so I used a different supplier. I talked to them and all seemed reasonable, so I've got my fingers crossed. I drive a 2000 Taco with a supercharger which, according to my supplier, will use essentially the same alternator as the naturally aspirated engine--I took him at his word. Was a bit pricey at $155, but what the hell.

Looking to also add a couple of cooling fans, I see you have done this. My FWC Eagle has an open lead at the fuse box that will work for these fans, but all the ground fittings on the fuse block are taken up. I'm not sure now about how to ground. My electrical knowledge will easily fit a teaspoon with a lot of room left over., I'm sure I have some options for grounding, but clueless as to what they are. I've read most of the "venting" threads on this site, but found no simple wiring diagrams/photos.

Thanks again for all the wise directions you sent me.

tdf