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Re: Another 7x17 CT build F150 2.7 Eco TV

PostPosted: Fri Dec 08, 2017 12:51 am
by McDave
Iconfabul8 wrote:If l were going to spend that much on a fridge l would go for a propane/AC/DC type unit. Is there a reason you don't want this type?


The LP/AC/DC fridges are ammonia type absorption units. They are not really what they appear to be. Liquid ammonia is heated causing vapors (gasses) to expand and rise where they absorb heat, causing the gas to condense back to liquid and return to the tank. That works pretty well with LP, but you still need 12v to open the LP solenoid valve and power the control. So it is not just LP. In the AC mode 120 vac is sent to a heating element that heats the tank, also works OK but much less efficient than Freon/compressor style. In DC mode they are terribly inefficient. Resistance heating gobbles power fast and yields little cooling power. Also they constantly produce heat adding to the inefficiency.
12 vdc/ 120 vac units are more efficient, chest type better than door style. Even a small domestic 120 vac fridge run from inverted 12 vdc is better.
Of course all of this is IMHO. I think if you crunch the numbers you will agree.

McDave

Re: Another 7x17 CT build F150 2.7 Eco TV

PostPosted: Fri Dec 08, 2017 3:33 am
by Iconfabul8
McDave wrote:
Iconfabul8 wrote:If l were going to spend that much on a fridge l would go for a propane/AC/DC type unit. Is there a reason you don't want this type?


The LP/AC/DC fridges are ammonia type absorption units. They are not really what they appear to be. Liquid ammonia is heated causing vapors (gasses) to expand and rise where they absorb heat, causing the gas to condense back to liquid and return to the tank. That works pretty well with LP, but you still need 12v to open the LP solenoid valve and power the control. So it is not just LP. In the AC mode 120 vac is sent to a heating element that heats the tank, also works OK but much less efficient than Freon/compressor style. In DC mode they are terribly inefficient. Resistance heating gobbles power fast and yields little cooling power. Also they constantly produce heat adding to the inefficiency.
12 vdc/ 120 vac units are more efficient, chest type better than door style. Even a small domestic 120 vac fridge run from inverted 12 vdc is better.
Of course all of this is IMHO. I think if you crunch the numbers you will agree.

McDave

Very nice explanation, definitely sheds some light on the subject, thanks. I just think of how nice it would be to light the fridge and forget about it. However, I can definitely see the probs on the AC/DC side of things. At this point I would have to go with a DC chest type and put it in the truck because my trailer is too small to even think about installing any type of fridge or cooler. :(

Re: Another 7x17 CT build F150 2.7 Eco TV

PostPosted: Fri Dec 08, 2017 10:09 am
by NotJammer
duncanshannon wrote:Cool! Excited to watch your build. How did you decide between 6' wide and 7' wide?


This is a stock size trailer and I thought I needed the width.

Too late now to change anything. I wasn't thinking quite right as I suddenly became very ill just before ordering. I decided to order a dream anyway and hope I would get well.

I am in good health now after 6 months of difficulty.

Onward!

Re: Another 7x17 CT build F150 2.7 Eco TV

PostPosted: Fri Dec 08, 2017 10:13 am
by NotJammer
I agree, 3 way fridges eat electricity. OK on DC if you never stop driving. I have used one extensively. An Engle uses very little DC.


McDave wrote:
Iconfabul8 wrote:If l were going to spend that much on a fridge l would go for a propane/AC/DC type unit. Is there a reason you don't want this type?


The LP/AC/DC fridges are ammonia type absorption units. They are not really what they appear to be. Liquid ammonia is heated causing vapors (gasses) to expand and rise where they absorb heat, causing the gas to condense back to liquid and return to the tank. That works pretty well with LP, but you still need 12v to open the LP solenoid valve and power the control. So it is not just LP. In the AC mode 120 vac is sent to a heating element that heats the tank, also works OK but much less efficient than Freon/compressor style. In DC mode they are terribly inefficient. Resistance heating gobbles power fast and yields little cooling power. Also they constantly produce heat adding to the inefficiency.
12 vdc/ 120 vac units are more efficient, chest type better than door style. Even a small domestic 120 vac fridge run from inverted 12 vdc is better.
Of course all of this is IMHO. I think if you crunch the numbers you will agree.

McDave

Re: Another 7x17 CT build F150 2.7 Eco TV

PostPosted: Fri Dec 08, 2017 2:58 pm
by McDave
Iconfabul8 wrote: At this point I would have to go with a DC chest type and put it in the truck because my trailer is too small to even think about installing any type of fridge or cooler. :(


I'm not sure I'm buyin' that. First of all, I know how clever you can be when you decide to confabulate something. I can almost envision some sort of cammed and dampered swing down affair that makes use of some otherwise dead space over the Throne or something that would blow everybody's mind cause you made it look so easy. ... :shock: ...
And secondly, I have a Norcold 12/120 in my 6 x 12 mounted at eye level above the Galley sink. It's about 2' x 2' x 2' outside, so maybe 1.5 cu ft inside? It has a little freezer and makes ice and keeps ice cream and frozen stuff solid. You could probably put close to a case of cold barley soup in there. I don't drink beer anymore so I just keep eggs, bacon, Jameson, cigars and water and ice cream, and Jameson in there. The problem with door style reefers is all the cold falls out when you open the door, so I try to keep it filled with bottled water and Jameson to store the cold in mass instead of air. It consumes 2.7amps at 12v, and runs about 12mins/hr depending on ambient temp. I only have (1) 125AMP deep cycle but can go for a few days before charging if I need to.

McDave

Re: Another 7x17 CT build F150 2.7 Eco TV

PostPosted: Fri Dec 08, 2017 4:27 pm
by NotJammer
Propane tanks! I may be able to put two 20lb tanks on my tongue. I may not want to. It will need a custom mount. I might put them inside a box in the vee with a big access door sealed off from the inside with floor venting.

That's the basic thought today. I am well aware of propane dangers. I had a Grumman 14K custom box truck in 1980. It had an underneath tank and furnace that worked great except when my propane filling station overfilled it by a lot one time. I never noticed a problem until I got to my large parking garage. It held 30 trucks. The attendant immediately noticed I was leaking and I had to park outside for several hours while it bled off. Indoors an explosive situation.

Don't some RV's have tanks in sealed inside boxes? I have seen a lot of people do this Euro-style to their vans. Still, is it a good or bad idea?

Right now I have an overfilled 10lb hooked to a Buddy and it burps when I move it. Not using yet. It's a temp for my shed.

Making DIY outside access doors. Any tips? I am going to cut this exterior sooner or later. Tin snips? Cutting wheel? Air Hammer panel ripper? Box knife? Tiny Milwaukee M12 Sawzall. I have the tools, but I hate the first cut. Doctors, any suggestions?

Re: Another 7x17 CT build F150 2.7 Eco TV

PostPosted: Fri Dec 08, 2017 5:48 pm
by McDave
Well, First your gonna need your finest quality titanium step drill bit. Draw up a template or two and find that big fat roll of blue masking tape. Decide where you would like to place the access door, then go take a look inside to be sure, then pick a different place to locate it and use that tape to mask the area you will be cutting and use that template and a level to mark the cut line on the tape. Now use the step drill bit to make a hole big enough to accept a metal cutting JIGSAW blade. You know what to do from there. Here's some example pics.
143607
143606

McDave

PS I have my LP tank located in a sealed and vented compartment. Sealed from the cabin, vented to the outside. That's important. I used vented door. I have the battery and pump in there too. Also I store the stinky slinky there. This is the only pic I can find. That is the vented door above the fresh water inlet and 30 amp shore power connection. I might know where you can find a scratch and dent door just like that... cheap. Let me know
151320

Re: Another 7x17 CT build F150 2.7 Eco TV

PostPosted: Fri Dec 08, 2017 7:15 pm
by NotJammer
Thanks, McDave

Got it.

I will need a 16 X 30 door with left hinge. I may make it.

Re: Another 7x17 CT build F150 2.7 Eco TV

PostPosted: Fri Dec 08, 2017 8:08 pm
by NotJammer
Found this long youtube, but good detail on access doors.

https://youtu.be/vlXKIBDOJZQ

Now where do I find these doors cheap?

Re: Another 7x17 CT build F150 2.7 Eco TV

PostPosted: Sat Dec 09, 2017 10:15 am
by hankaye
Howdy All;

About that propane thing ... PLEASE be sure to install one of these.
http://propanedetectors.com/
I have one in my home (5th wheel RV), and I'm hooked to an external
tank. They install near the floor as Propane is heavier then air, so the vents
should be in the floor as well. My 30# tanks ride on metal supports above 8"
holes in their compartments.

hank

Re: Another 7x17 CT build F150 2.7 Eco TV

PostPosted: Sat Dec 09, 2017 11:52 am
by NotJammer
Good ideas! But I see it only runs on 120 vac. I think we need battery powered.

I cannot find any real regulations for RV propane. Mobile homes have different rules for tank sizes. Under 125 lbs and above.

https://www.tripsavvy.com/rv-propane-safety-505111

http://www.rvia.org/?esid=standards

Here's what I might do. Steel lined cabinet with big holes in the floor. Opens only to the outside. Leak detectors no matter what I do.

Imagerv-propane by moe.randy, on Flickr
hankaye wrote:Howdy All;

About that propane thing ... PLEASE be sure to install one of these.
http://propanedetectors.com/
I have one in my home (5th wheel RV), and I'm hooked to an external
tank. They install near the floor as Propane is heavier then air, so the vents
should be in the floor as well. My 30# tanks ride on metal supports above 8"
holes in their compartments.

hank

Re: Another 7x17 CT build F150 2.7 Eco TV

PostPosted: Sun Dec 10, 2017 4:31 pm
by McDave
NotJammer wrote:Found this long youtube, but good detail on access doors.

https://youtu.be/vlXKIBDOJZQ

Now where do I find these doors cheap?


PM sent.

McDave

Re: Another 7x17 CT build F150 2.7 Eco TV

PostPosted: Fri Dec 22, 2017 5:56 pm
by sodatrain
I'm def thinking 7' wide.... do some of you not like that width?

Re: Another 7x17 CT build F150 2.7 Eco TV

PostPosted: Fri Dec 22, 2017 6:18 pm
by billbob412
duncanshannon wrote:I'm def thinking 7' wide.... do some of you not like that width?

I have a 12x6 and a 12x7 and the difference is huge in my opinion. I needed the extra foot to fit my ural in .It really opens it up and feels much bigger.

Re: Another 7x17 CT build F150 2.7 Eco TV

PostPosted: Fri Dec 22, 2017 6:35 pm
by hankaye
billbob412, Howdy;

Mostly the width is dependent on where you expect to end up.
Me I head to the Gila Wilderness and find my self on skinny Forest
Service Roads so I have a 6 foot wide CT. It is also closer to the
width of the tow vehicle, less drag ='s better fuel mileage. It also
fit parking slots better. The above is only my thoughts and opinion,
YMMV.

hank