Freezer/Refrigerators, portable

T

thataway

Active member
I was going to discuss this issue, in " lessons from Lake Powell", but I have a "problem" which I am trying to solve.

We have a Dometic (WAECO--was Adler Barber)-portable chest refrigerator/freezer: 0 - 50 degrees, 50 quart size. It was purchased June 2012. We used it that summer, and at Lake Powell, it maintained 5 degrees (LED read out on the chest) with about 50% run time--and a 24 hour 30 amp draw out of a 110 amp hour AGM battery.

This summer at Lake Powell, we kept it "set" at 5 degrees LED readout, and the lowest we saw on the boat was 8 degrees LED readout. Most of the time it was 9 to 13 degrees--average 11 degrees. The compressor was running all of the time, and we were drawing about 60 amps per 24 hours out of two identical batteries in parallel--both 110 amp hours. No problem, since the food was well frozen, but it was a concern. Pat Anderson on Daydream had a similar size ARB--and it was running about 50% of the time, and Scott on Little Bit, had an identical (but newer), CF 50. His was also running about 50% of the time and set at 5 degrees.

I plugged it in at home, and dialed it down to 5 degrees, and it got down to about 6 degrees in our home-Ambient temp was 73 degrees. At Lake Powell, the Ambient was closer to 93 each day, and even at night in the mid 70's. I have called and may have found a tech who will check out the unit at our home (most of the "service centers" listed by Dometic have no idea even what the CF 50 is!)

So as an experiment, I put two 1/2 gallon containers of water, in the freezer, and turned it down to 31 degrees. In about 4 hours, the water was beginning to freeze, and the water temp was 32 degrees. The unit was cycling on and off to maintain the temp at 31 degrees, as indicated on the LED readout.

Next as a further experiment, I put a bottle of 70% isopropyl alcohol (freezing point minus 35*) in the freezer, to measure the temperature of liquid--simulating what a hunk of frozen food was at. I also put an indoor outdoor thermometer in the chest. I turned the freezer down to 10*F. After 3 hours the LED temperature reading was 18*, and has stayed there, for 5 hours now. The compressor is running constantly. At 4 hours, the alcohol was 13 degrees, and the I/O thermometer was at 5 degrees: at 5 hours, the alcohol was 10 degrees, the thermometer was 4 degrees: and at 6 hours the alcohol was 7.4 degrees, and indoor/outdoor thermometer was at 3 degrees reading in the freezer chest--(the LED readout continued at 18 degrees).

I figured that the caloric intake of freezing the water is at a balance with the freezer, and a reading of 18 degrees by the LED readout. (We don't know how or where this is measured). But we know the both the liquid temperature (alcohol) and inside the chest temperature is still going down (the I/O thermometer).

So, the problem may well be a "false" reading--and also a false coupling with the compressor circuit, instead of an actual compressor problem.

I anticipate that soon all of the water will be frozen, and the temp reading of the chest will begin to go down, and stabilize at 10 degrees LED reading--there should then also be an equilibrium with the temp of the chest (I/O thermometer) and the temperature of the liquid alcohol.

Thoughts of the group?
 
Yes, we are running on 110 Volt AC, and the Kil-o-watt reads 39 watts, and .56 amps. The cumulative showed 50% run time last night, with a stable (empty) freezer LED reading of 13 degrees. The cooling ability seems about the same with the 12 volt DC and the 110 V AC power supply. But we only read how many amps we put back into the battery when on the boat.
 
Sounds like the temp sensor is bad and forcing the compressor to work from that false number never reaching its goal. Is there a replaceable temp sensor on that model?

Greg
 
Sounds like the temp sensor is bad and forcing the compressor to work from that false number never reaching its goal. Is there a replaceable temp sensor on that model?
Click to expand...

Greg, does not look to be an easy swap--the sensor is probably in the wall. There is one record in the internet of a bad diode and a broken circuit board which gave a similar problem.

The temp sensor has been varying--but you make a good point--and I had attributed that the sensor had not gone down, as the caloric intake related to freezing the gallon of water. I will do further readings tomorrow, as the temp comes up, and I reset the temp to something in the 30 degree range.

It does take a bunch of calories to freeze a gallon of water (3780 grams) x 80, plus the cal to lower from 21 degrees C to 0 C….I'll check to see if all of the water is frozen now…

Greg, you posted that link when I was typing this reply--and this is certainly a possibility. So far I have not been able to talk to a tech at Dometic (not even sure where these units are built today, and if they are the same as there were 6 years ago).

Brent, these compressors (Danfoss) take very small amounts of refrigerant--2 to 3 oz. No sign of any leaks and the unit is cooling very well. I have built 3 eutectic holding plate, Freezer/Refrigeration units on boats,-combo engine driven/120 volt AC 2 compressor systems, and have a set of gauges etc, I would not touch one of these small systems. They are sealed units; no Schrader valves. One of my friends who had a marine refrigeration business would not touch one of the Norcold compressor units. The local tech I talked to felt it was not low on gas, because it was cooling well. Hopefully he will get by on Friday.

I rechecked the unit, and it has dropped to 16 degrees--the water is 100% frozen. The inside of the freezer is at zero (by the I/O thermometer) and the alcohol is at 6 degrees. I decided to leave the unit at a setting of 16 degrees for the night--and record what the KWH is over the night, after recording the KWH, and HR reading at 10AM. This will give me an idea of run time over the night--and then I will let the temp come up in the AM--and see where it stabilizes--lets say set at 24 degrees. Compare that with the 16 degree setting.

At the lake we had the "jacket" on the unit--and also had a 1/2" thick styrofoam cover, with foil on the top as addition insulation, plus kept it in the shade as much as possible, and had a white towel on just the top of the foam/foil. There is definitely heat loss from the top and sides: The ambient temp is 72.5* in the room, the top of the freezer is 66.6, sides 67.6, one vent 108.5, the other 90.2 (max readings).

I have to laugh--when I built boxes for the boat systems, they had from 4" to 6" of closed cell foam, with fiberglass interiors, and vapor barriers--with double gaskets, 3/4" thick. This thing has a single 3/16" gasket, right around a lip in the lid. Max insulation, in the top--maybe an 1 1//4"--sides appear to be about 1 3/4".

I think that Greg is correct that there is a sensor problem. Now to see how to repair it?
 
thataway":2nbhfv3n said:
I have to laugh--when I built boxes for the boat systems, they had from 4" to 6" of closed cell foam, with fiberglass interiors, and vapor barriers--with double gaskets, 3/4" thick. This thing has a single 3/16" gasket, right around a lip in the lid. Max insulation, in the top--maybe an 1 1//4"--sides appear to be about 1 3/4".
Click to expand...

I recently bought a CF-50 on the closeout sale. The new models look nice, but most sizes aren't available here yet from what I could see (only found the really small and really large), and it looks like they no longer have Danfoss compressors.... so who knows if they are better or worse... ("genuine Waeco compressors" now).

Anyway, I know what you mean. I'm used to sailboat iceboxes and these seem so thin! Especially the lid. I'm used to the super thick ones with stepped insulation.
 
I concur, it appears to be electronic vs mechanical issue.


These are expensive units and hopefully easy to troubleshoot and made to be repaired but most likely items cannot be repaired just "RnR It" - remove and replace and crazy expensive

We use dry ice at work for packing and shipping some specimens, the rest is shipped ambient temperature and with cold packs. It works well but expect dry ice is not easy to locate. Our high end dry ice storage box can hold dry ice for about week without evaporating


Go well
 
Only two years before it starts screwing up by running constantly. What's the warranty on those units? Seems like they should hold up better than that. I guess I would try to talk the manufacturer. Don't they have a tech line? If not, I myself would be looking at other brands that offered better customer service. JMHO
D.D.
 
DD,
Good questions. I have no experience with these units but have recently started looking at the possibilities here.

Bob, Thanks for bringing this up, and sorry for your hassle.

Harvey
SleepyC :moon
 
After reading this I'm likely to keep buying ice at the marinas. I have to stop every couple days for gas if we are on the run anyway. 800 dollars buys a lot of ice, no tech line needed. Plus no battery worries from refridge draw. Cancel the solar panels also. We use the resulting water for the dog drinking water anyway.
D.D.
 
Dave, the warrantee is 2 years. I purchased the unit on 6/06/12--so when I called it was out of warrantee. I sure agree that this price unit should last longer than it has. So far everyone I have spoken to at Dometic says call this local service facility--most of which are dead ends. One listed on the web site was an outfit about 2 hours away, which mostly sells sheds and carports, but also carries Dometic parts. Two I got on the phone were out of business. One is a fellow I use, but he contracts out air conditioning, and refers, the one local one has no physical address, and the phone is a cell…but if he can do the job? ? We will see. If not I'll have to start turning stones at Dometic to talk to a tech. A few years ago, I would have taken the unit apart, if I hadn't gotten an answer--today I am physically too limited by health issues.

This morning the LED read 16, the freezer I/O thermometer was at zero, and the alcohol was at 5.1 degrees. Currently the temp is up to 24 on the LED and the laser is 17 off the top of the water containers, and 13 on the inside/bottom of the freezer/refer chest.

In 10.7 hours the unit had used 380 watts--pretty much full time over the night! I upped the temp to 24 degrees, and currently the unit is cycling off "normally". We will see what the current use is at this setting over the next 8 to 10 hours, and then up the temp to 34 and see what the current use is.

So far my conclusion is that is would be prudent to get a wide range digital thermometer (Taylor, minus 40 to plus 450 F--$14.95 at WalMart) to monitor the temp in the freezer when using it. The laser temp also helps--and seems pretty close to the alcohol measurement.

Part of the issue, is that ice is not good quality on Powell, and lasts 3 to 4 days max, even with good coolers (of course, we are in and out, putting in beer etc.). In our case we have a high end ice chest, and keep a wet white bed spread over the cooler, to help keep the temp down, and decrease the ice usage. Another option that Pat Anderson and I were discussing, was a second refrigerator unit--larger running off 12 volts. I think my current run time of 2 hours a day, with two group 31 batteries would support this unit (operating properly), and a larger unit at 36 to 38 degrees. Of course this is not cheap--but if you are on the lake a month--and running to an ice store every 3 days, is not only inconvenient, but also expensive (ice is over 50 cents a lb on Powell).


Thanks for all of the comments! The general consensus in reviews seems to be positive for the Dometic product. I had excellent service from the older Norcold, which had swing motors.

Sunbeam,--I suspect that these units are currently made in China--and a copy of the Danfoss compressor currently. Several of the units have "turbo" mode, which suggests that they are using a compressor which has variable speeds.
 
A trick I have learned for protecting insulin in a car during the summer is a damp terry cloth towel. The evaporative cooling does wonders. I suspect a large towel refreshed occasionally with Powell water sitting over any cooling device, ice box or electric, would contribute a lot of cooling.
 
Speaking of ice and coolers - although I bought a CF-50 before heading out on Powell, I wasn't able to get the supporting items on in time (solar/battery, which I want anyway for other things), so I used a new cooler I had bought. It claims to keep ice 6 days. Of course it all depends on many factors, but the "days" claims may at least have relative merit between similar coolers.

That said, in my case it really did keep ice 6 days, and that was starting out with just one "fake block" (chips pressed into a block) from the Wahweap campground store. High temps were around 80ºF and due to the dry climate, I kept a wet towel over the cooler lid. Bought the ice Sunday and it finally melted on Saturday. Not too bad for a 58 quart cooler with one block (and contents did not start out cold from "home," either). Certainly leagues better than my previous cooler.

The cooler is a Coleman Ultimate Extreme Marine. It's a bit hard to find vs. the Extreme Marine (non Ultimate), which is a 5-day and slightly larger capacity (due to less insulation - same exterior size). This one has stainless hinges and one of those springs that stays stiff when fully extended (to hold lid open), then you touch it and it "collapses" and you can close lid. Plus one tray. It's no Yeti, but I'm pleased with it (price was also more "Coleman" than Yeti).

I will still hook up and try the CF-50, but will also keep the cooler - just depends on variable trip factors which (or both) I'll use, I suspect.
 
Not sure how we got to coolers--that is another subject. The coleman Extremes have had excellent ratings. The average ambient temp at Powell in the last week has been about 15 degrees cooler than earlier in Sept. Big difference. Yes, most of us put wet towels/bedspreads over the coolers to use the evaporative cooling effect.

Back to the subject. The LED temp is up to 24 constantly and now the compressor is running about 50%. The alcohol temperature is staying at 13 to 14 degrees, and the IR temp on the top of the ice is 14 degrees. The i/O thermometer is reading about 12 degrees. (this is an alcohol tube type of garden thermometer, and not easy to read).

The problem is the reading of the thermistor/sensor/LCD read out, and probably this is effecting the run time. Most likely we had the real temp in the freezer at Powell close to zero F. or even lower. We will next test the temperature when running at temperatures in the mid 30's--or refrigerator.

If I cannot get the sensor fixed, I can still use the unit and set the temperature accordingly--using a thermometer to measure the temp.
 
thataway":21asnlrq said:
Not sure how we got to coolers--that is another subject.
Click to expand...

Sorry :oops: I guess it started with ice box/built in design, then someone else said they might as well buy ice anyway since they stop for fuel, and then I ran with it. Mea Culpa. Since I haven't even run my CF-50 yet, I had no business posting.
 
thataway said:
Dave,
Part of the issue, is that ice is not good quality on Powell, and lasts 3 to 4 days max, even with good coolers (of course, we are in and out, putting in beer etc.). In our case we have a high end ice chest, and keep a wet white bed spread over the cooler, to help keep the temp down, and decrease the ice usage".

Dr. Bob,
I'm just guessing that this might have been reason the poster brought up coolers. As an aside the ARB units are reported to have a three year warranty.
D.D.
Click to expand...
 
Will-C":1bwy2xmm said:
After reading this I'm likely to keep buying ice at the marinas. I have to stop every couple days for gas if we are on the run anyway. 800 dollars buys a lot of ice, no tech line needed. Plus no battery worries from refridge draw. Cancel the solar panels also. We use the resulting water for the dog drinking water anyway.
D.D.
Click to expand...

For those who have not been to Powell, it may be difficult to understand what the problem there is--and why one might want a freezer or a refrigerator. Basically there are only 3 places to get ice on Lake Powell. One is Wahweap, or Antalope at the "bottom" of the lake, where many put in. The other is about 40 miles up the lake at Dangling Rope--one time then only 3 blocks of ice left. The 3rd is Halls/Bullfrog, at mile 100, and where some others put in. So it is not as though one runs by a marina each day, or even every other day.

For example we spent 4 days up in the San Juan Arm. We would have liked to spent more time. We had plenty of fuel, and water, but had to run almost 100 miles to get ice. The freezer had main entrees for a month, and that was not a problem. Sure, I have done back packing for weeks, with dehydrated foods, and that is an option, but not our choice currently. Thus we are considering a second compressor run chest to use as a refrigerator on Powell.


I can get a 80 quart Dometic for $749, or a 110 quart for $789. The ARB is $1229.(with a 3 year warrantee) My Norcolds lasted 15 and 20 years--(but that may not be the average). There is even a better one: The National Luna--currently the closest available to the above is a 90 liter unit, and it is $2600! Are these pricey, and luxury items?--absolutely. But at a certain point in life they may be "worth" it.

there are several reasons, as well as price I choose the WAECO/Dometic. Part was the excellent reputation of WAECO--may not hold true now..The units handles are easily detachable--taking less space. The shell is a rugged plastic, rather than steel--which I have had rust in previous units. I liked the design and features.

Is the ARB better than the Dometic? Probably. As for power use--Pat Anderson can address that. My impression was that it was more than advertised.

Last night over 12 hours, with an internal freezer temp of 28 degrees, the current draw was 0.8 amps per hour. (about what we would expect from the ARB). Granted this test was a long way from conditions at Powell when we were there (but fairly close to what Powell is currently).

One thing we do not know is how the current draw tests may have been done on 12 volts: Many times this is using a 13.8 volt power supply--a bit different than the boat battery which will run from 12.7 to 12.2 volts. This may be one factor which accounts for the difference between advertised 12 volt draw and actual 12 volt draw.

An excellent review of various units is at:
http://expeditionportal.com/overland-jo ... ge-review/
They used basically the same battery I am drawing. (Group 31 AGM).
 
Thanks for the additional details. Holding frozen food for over a week on a small boat is not a trivial task. I may get to that point in a few years, health holding. For now 3-5 days will suffice - that is a trivial problem.
 
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