New 4.3 & 6.7 fridge info

[rbryan4]

I do think you are looking at the best option. If mine ever kicks the bucket I will probably go to a compressor model since I have lots of batteries and solar.

Yep. That's why I'm getting the dual 6V batts, and the panel. I may add a second panel and maybe more batts as well, but we don't plan to be off grid that much, so we'll probably just stick with the one panel and two batts to start. We'll see how it goes.

 

[Brian B-P]

Those figures are maximum - power when full cooling is required. And if it has more cooling capacity I would expect it to either cycle on and off (like a compressor) or run partly on (like a stove burner) - it would still have a thermistor and temperature (bar) selector.

Yes, they cycle as required.

 

[hotfishtacos]

Yep. That's why I'm getting the dual 6V batts, and the panel. I may add a second panel and maybe more batts as well, but we don't plan to be off grid that much, so we'll probably just stick with the one panel and two batts to start. We'll see how it goes.

...and Bryan, best of luck to you when you receive your new trailer, "Past Tents"!

 

[Parker-ESC]

Adding more batteries and panels for a compressor fridge got me thinking about all that weight for towing, which got me thinking about running on 12V while towing since propane is no longer an option. How much current do these compressors fridge require? I hope it's less than for the 12V heating element for adsorption fridges, as that's already more than most tow vehicles can provide and still keep the batteries charged on the camper. My guess is they don't require huge current to run the compressor; hope that's the case, anyway.

 

[floorpanel]

I run on 12v when I am towing and have never had a problem. The solar panel in addition to the tow vehicle power has always been sufficient

 

[Parker-ESC]

Which fridge? Ours is the 6.7. We have large wires for the charge line (and solar with dual 6V), but the few times I tried it I remember the battery ending up at something like 12.4V at the end of the tow. By the time we get to our destination, if off the grid, we don't have much time for solar to bring it back up. You have me wanting to try it again, maybe switching back to propane later in the PM to let the house battery charge back up.

 

[floorpanel]

I guess I was a little misleading. Probably 90 percent of the time I have hookups when I arrive at the camp site. On a couple of occasions when I didn't have hookups I made it ok but I had several hours of sun to bring the batteries back.

 

[rbryan4]

How much current do these compressors fridge require?

I started a thread on NovaKool compressor fridges some time back. There's some good info from forum members there on the power requirements. The Danfoss compressor based fridges are surprisingly efficient:

http://www.escapeforum.org/forums/f9/ac-dc-refrigerators-4178.html

 

[Brian B-P]

How much current do these compressors fridge require? I hope it's less than for the 12V heating element for adsorption fridges, as that's already more than most tow vehicles can provide and still keep the batteries charged on the camper.

Details are in the thread rbryan4 linked, but in rough terms the compressor-based refrigerators will use half the current of the absorption type... when they're running, which should not be all the time.

The limitation on current supply by the tug is in voltage loss over wiring, not the tow vehicle itself. The few amps used to run an RV refrigerator is nothing to a modern car or truck... but that's a different topic!

 

[Parker-ESC]

I went back to look at the compressor fridges and agree that the current numbers look pretty good. And I'm pretty familiar with the voltage drop issues and difficulty pushing electrons into the camper battery while the tow vehicle is running at it's normal voltage. Didn't mean to take into that territory with this thread!

 

[cpaharley2008]

Something has been nagging me throughout this entire process and today I figured out what it was. Has anyone kept a record of the freezer/refer differential? I turned mine on yesterday to chill down in anticipation of using it this weekend. My refer on the middle setting this am was 44 and the freezer was 3? It would seem to me the freezer's temperature would be the benchmark we want to achieve. If the freezer is below 10F then the refer is operating efficiently and it is just a matter of getting some of that cold air to the refer section? Either removal of the freezer section or the drilling of some holes to allow some interchange will help achieve the optimal refer temperature. The freezer is fine as it appears.
Anyone else has ideas on this train of thought?

 

[MyronL]

I was thinking the same thing. Did not want to drill holes in it so removed entire unit. Seems a logical way to increase general cooling. We will always bring along a separate cooler filled with ice anyway. When exploring the possibilities of installing a baffle in back I discovered the shell in mine there is insulated. Since the jury seems still out on efficiency of the baffle idea I've decided to hold off on that.

 

[tractors1]

Similar thoughts here, but I'm 2 weeks out from pickup on my 21. Planned on doing experiments with the freezer geometry when I have one to play with...

 

[cpaharley2008]

I bought some of these thinking I can drill some holes in front and in the rear of the freezer bottom insert and plug/open both or one set to see if the desired result is reached. I'm also thinking of purchasing a second freezer inset to practice with and then leave the original as is. Depends on the price they want for the insert.

 

[tractors1]

I bought some of these thinking I can drill some holes in front and in the rear of the freezer bottom insert and plug/open both or one set to see if the desired result is reached. I'm also thinking of purchasing a second freezer inset to practice with and then leave the original as is. Depends on the price they want for the insert.

I'll be making a dummy insert out of sheet ABS to experiment as I have a LOT of it...........

 

[escape artist]

I bought some of these thinking I can drill some holes in front and in the rear of the freezer bottom insert and plug/open both or one set to see if the desired result is reached. I'm also thinking of purchasing a second freezer inset to practice with and then leave the original as is. Depends on the price they want for the insert.

Hi: cpaharley2008... If I were drilling holes I'd do them at the front of the freezer. I don't think it would be good to have more cold air falling over the thermistor mounting. Could fool it into thinking the refer is colder than it is. Just thinking!!! Alf
escape artist N.S. of Lake Erie

 

[hotfishtacos]

Jim, if you haven't drilled your holes yet why don't you try taking the front door off the freezer first. This way you will preserve the barrier between the freezer and refrig and won't flow cold air onto the thermister in the fridge.

 

[tractors1]

Just a thought - if the thermistor were wrapped in a thin layer (1/16th inch) of foam, cold moving air wouldn't impinge on the surface, but it would eventually cool to the ambient temperature. Basically just slow down the response of the sensor, since the fridge cools slowly anyway. Ain't theories grand?

 

[dave macrae]

I pondered lightly insulating the thermistor as well. The other angle that popped into my head was that it may negativley affect the performace, in that the fin its on is cooler than the air around it, so would you be fooling the thermistor that it is cooler in the fridge than it is by keeping the warmer air off of it? I don't know the answer but those were my thoughts. I suspect that , more of a shield type of a idea to keep the moving air from fans off of the thermistor might be a better idea.

 

[Kountrykamper]

I have the freezer removed most of the time and have purchased extra shelf's to use when its out and to replace the crisper. It drops the fridge temps 6-8 degrees from what I have seen. Like I said in another post, I froze the lettuce last weekend which made me happy but Cheryl was not nearly as excited as I was.

Just my opinion but I would wait for Reace before drilling holes in the freezer. He is already experimenting with that. Dometic is probably going to take a while to get back with him.

First picture is a old picture as I have now removed the Fridge Fix fan because it was driving my temps up 4-6 degrees. I insulated the sensor and tried several things. I tried it with the freezer in and out. I have installed a small Axial fan (19 CFM) blowing down with very good results so far. I will do a permanent install if it continues to work good but right now we are trying to get in as much camping as we can.