isotherm refrigerator Vs norcold refrigerator ?

[Viva]

That's actually what I have been figuring for an "average" day: 48 amp hours. This would be for the Vitrifrigo 130 with added insulation (somewhat like you did). Not sure if I'll end up being right, but that's the figure I've arrived at by some facts and some "by guess and by gosh." That'd be by far the biggest draw on my system, and will be driving my solar setup.

I've decided (for various reasons) to set up a temporary system for part of the summer (I'm going to be parked at a friends who lives off-grid, so I can't just plug in) which will consist of two 100-watt panels that I'll set out on the ground, and a Dometic 50 liter cooler-shaped refrigerator (which lists a similar draw even though it is a lot smaller, maybe partially because they are not all that well insulated.

So, I'm going to see if I can get a feel for how much the smaller Dometic draws, and how much the 200 watts puts back. Then I'll feel more comfortable going ahead with "permanent" stuff. Plus it's something I can rig up relatively quickly for this one trip/parking situation.

[Scalf77]

Once I get by some household projects, I have plans to replace my refrigerator later this summer. The biggest hurdle is my wife wants to up-size, and I will need to do some cabinet work. But I have been putting some things together to log the current and duty cycle on the fridge. So I hope to do some real life measurements before and after change. I am looking at the isotherm units.

-greg

[rockbender]

Our old van had an Isotherm 130 (no ASU) with the Danfoss compressor. I recall the draw on that unit being between 3.9 and 4.3A when running. We put a Truckfridge 130 in our new van which has an updated Secop compressor (still Danfoss more or less - I haven't researched the relationship of the two companies) and I see more in the range of 3.3 to 3.8A while running. The other variable in my scenario though is a different battery monitor - I had a Trimetric in the old rig and now am using a Victron Energy.

The Isotherm was running really close to a 50% duty cycle I believe, so the 48aH in 24 hours was what I was roughly using as well. Once I run the truck fridge a little more hopefully I can report back some more information on its performance.

FWIW Greg, the 130 size fridge was one of the design constraints set forth by my wife on the new build. No complaints from us!

[daveb]

Originally Posted by Viva

Wouldn't an actual comparison be nice? Plus, in a way who cares how many amps it draws (within reason), if it has a super low duty cycle. Between amps and duty cycle, it seems almost impossible to get a real comparison. I would like to see two figures: 24-hour damp draw, at X temp setting, at 60º ambient temp, and the same thing with a 90º ambient temp. That would tell us a lot.

That's one reason I decided to go separate compressor. I figure I can insulate the heck out of the box, and ventilate the heck out of the compressor, and nary the twain need to meet.

I like Len's added door insulation - that has got to be a weak point on most of them.

As warm as the compartments against the door get compared to the inside of the fridge I've thought about insulating the door face. Obviously over insulating the box would be the best method of keeping cycling down but I just don't have the room to do that or find space for an external compressor. So I'm just looking for the lowest overall draw in a 24 hour period with a drop in unit. I don't know if there is a linear straight line or curve in respect to air temp and cycling so maybe 60* is a good set point or maybe even 70. I guess I'd be wondering how heat vs insulation react in high temps. My link-10 can do measurements but unfortunately I never did any with the old unit so it's a best guesstament at this point. Unfortunately I'm relying on the state of my batteries and that might have changed.

[Ketcham]

The Pacific NW is having somewhat a heat wave lately and when I took the family camping I placed three Zico coconut water tetrapacks in the freezer--filling the entire freezer volume. This was placed the night before leaving along with some of the refrigerator contents that was topped off morning we left. The entire trip, the amp draw was significantly less- up to 50% while the inside of van remained hotter than average when we were on our daily adventures.

We would use the Zico ice blocks in our SMB Vitamix for smoothies. ...our house Vitamix became the van vitamix when I left a spoon in the blender and turned it on Later, after its replacement, I discovered the nut at the base acts like a sheer pin and breaks in such situations preserving the motor. $15 and 5 minutes later we had two. Have not looked back since. I lives behind the driver's seat.

Up until recently, I rarely used the freezer.

-j

[yelnam]

Bump. Any more info on Isotherm vs Norcold etc?

[jkolodzinski]

Originally Posted by daveb

Sorry but you're looking at old info off the Norcold site. The 4E pulls a whopping 6 amps now @ 12vDC. SMB tested several, two of which were installed in my van. I was told all the other Sportsmobile sites are seeing the same. According to SMB, Norcold finally admitted they have installed a new improved compressor. Both the small and larger unit (like I have) now pull more than double the amps when cycled on than previous year models. Of course that doesn't mean much if the new compressor takes half the time to reach a desired temp compared to the older model. It's amp hours that matter and what they use to reach a specific setting. Still I was very upset being I talked with them and they claimed no changes were made. I have not taken the time to see what the total AH of the new unit actually pulls.

Norcold NR751 uses about 3.75 Amps when running. In temperatures about 80F the compressor is on 50% of time. In 24 hours uses approximately 45 Amp-Hr.

[daveb]

Originally Posted by jkolodzinski

Norcold NR751 uses about 3.75 Amps when running. In temperatures about 80F the compressor is on 50% of time. In 24 hours uses approximately 45 Amp-Hr.

I only am going off what SMB found which is the same results I got and that is dealing with the larger 4cf fridge. However SMB told me even the smaller units are pulling more because that fridge also had an upgraded compressor as well. Sorry I never tested the smaller unit. If I could could have ordered an older DE0041 before they started installing the new compressors I wouldn't have been so disappointed with Norcold. And by them not updating their web site with the correct info on what it draws is BS IMO. I haven't looked at their website lately but the last time I checked all they were posting was about the new compressor and how it was supposed to be a improvement. But again I'm only looking at running amps not total amp hours per specific outside temps and at what setting the fridge is set to. If I had to do it all over I'd be looking more carefully.

[jkolodzinski]

I think, looking at the running amps only is a mistake. The smaller NR751 has a newer compressor, Danfoss BD35, which is used in many efficient 12V refrigerators. Older ones may have lower running amps, but cycles more often. I will test my 2.7 unit for longer time, and different ambient temperatures, to give you a definitive answer. In this forum, you can find a lot of praises for this compressor. Most of the posts agree that Danfoss BD35 is very efficient. It is made in Germany.

[jkolodzinski]

Originally Posted by daveb

I only am going off what SMB found which is the same results I got and that is dealing with the larger 4cf fridge. However SMB told me even the smaller units are pulling more because that fridge also had an upgraded compressor as well. Sorry I never tested the smaller unit. If I could could have ordered an older DE0041 before they started installing the new compressors I wouldn't have been so disappointed with Norcold. And by them not updating their web site with the correct info on what it draws is BS IMO. I haven't looked at their website lately but the last time I checked all they were posting was about the new compressor and how it was supposed to be a improvement. But again I'm only looking at running amps not total amp hours per specific outside temps and at what setting the fridge is set to. If I had to do it all over I'd be looking more carefully.

More information: I tested the fridge at my driveway, at about 50 at night and 65 during a day. The compressor was on much less time. The unit stayed cold for 24 hours and used only about 20 Amp-hr. The temperature difference is very important. At 90, you're have to take 90-35=55, but at 55, 55-35=20. Do you see the difference? You can sleep in your van at 55 if you take a goose dawn comforter with you. Happy camping.