So I swallowed a bird to catch the spider...

[Vagabound]

That's a good question, and one I'm still trying to decide. Here are the 3 options:

1) Stay high and duct it out top of rear wall. Least desirable.

2) Drop duct down, still out back wall, but low enough that vent is hidden by lift gate...so about 3' high on wall.

3) Duct it out floor. Most desirable.

So. Heat rises, and AC exhaust is pretty warm...

...

"Don't know much about his-to-ree; don't know much bi-olo-geeee ...." 

(or spelling ;-)

Gonna ask a silly newb question:  I'm sure there must be an important reason there's no Option 4) Vent hot air UP through the roof, with a very small, low-profile rain-proof vent cover?  Something that would rise only a few inches and stay below roof-rack level.  Seems it would be going in the right direction to begin with, and then travel the shortest distance. To borrow an earlier suggestion, maybe it could be a two-way duct/vent and draw cool air in as well.

Vagabound

 

[BradKW]

The roof would have been a nice solution, but unfortunately the panels that power the AC cover it up:

[img=400x300]http://i465.photobucket.com/albums/...ads/IMG_20160821_200257_zpskijuthwd.jpg[/img]

I'm basing airflow off of 130 CFM which is a 6" round duct according to charts, which is about 30 sq/in...which to fit would be long and thin, say 3" x 10", which would have not only required a custom snorkle, it would be perched right on edge, look bad, and cast a shadow. The clearance under the panels is basically non-existent...goes from 1.5" outside, to almost rubbing across middle.

I certainly toyed with other ideas too...main one being ducting to MaxxAir fan and have it serve as exhaust. That actually was my plan when I decided to move AC from rear to middle, but it didn't work out due to bed lift...

 

[jimindenver]

You really should get some air flow under those panes. They put out less power the hotter they are.

 

[BradKW]

My theory on airflow under panels is that as long as you're not trapping the heat, it won't make a noticeable difference whether they are 1.5" or 3" off the roof. Glass covered panels all have the 1.25" frames (or about that), and those frames create a sealed box underneath every panel...if it's mounted flat, the it takes the same amount of heat buildup for the air to displace down and "bubble" around and over edges of frame.

Regardless, the panels are done and not moving, and I'm happy with the fact they can't be seen when standing on the ground. And it took nearly as long to install them as it did to come up with that theory...so please accept it as fact

 

[ZoNiE]

Has anyone considered taking a window shaker apart, removing the refrigerant, and remote mounting the condenser with a separate fan, say under the vehicle, and basically converting it into a split system? You'd be adding maybe 6-8 ft of copper lines and a few more ounces of refrigerant, but you'd be truly stealthy without a huge duct-box-cabinet thing radiating heat inside the vehicle.

No matter how much ducting you add to move the heat out, some heat will still radiate from the thing.

 

[jimindenver]

You would need a fair amount of clearance and the hum can be heard if there isn't masking noise.

 

[BradKW]

Moving along this weekend, got some more progress. The entire wood frame assembly has up til now been easily disassembled for changes, alterations, access, etc...finally was time to take it apart and put it together permanently. Makes me a little nervous...every time I think I don't need to take it apart again, something else pops up. And when I say permanent, you can climb on it like a jungle gym and nothing budges.

Air comes through floor vent then travels under the insulated refrigerator "floor" to the wall, where it goes up to AC. About to drop fridge floor in permanently:

[img=500x400]http://i465.photobucket.com/albums/...ads/IMG_20161016_110550_zpswv9t5h3c.jpg[/img]

 Exhaust vent cut in wheel well, about to install shroud:

[img=350x475]http://i465.photobucket.com/albums/...ads/IMG_20161015_120732_zps4dkwprcx.jpg[/img]

Walls are double pieces of 3/4" rigid foam board, both to insulate the fridge and to insulate living area from outside air and AC exhaust. I came up with a system that basically allows board installation with only perimeter attachment using adhesive. I continue to be impressed by Sikaflex 221. 

I do three things which result in a wall solid enough to...well, I don't know, but it's solid. This should also eliminate potential for foam-squeaking.

1) pre-caulk all butt edges of foam and rub it in with a gloved finger,
2) pre-caulk wood edged, tool with putty knife,
3) scallop board edges for more caulk.

[img=400x400]http://i465.photobucket.com/albums/...ads/IMG_20161016_115550_zpsi9aun6nw.jpg[/img]

Temporary braces allow fine-tuning fit and shimming the sandwich:

[img=350x425]http://i465.photobucket.com/albums/...ads/IMG_20161016_121435_zpsrbxck9ep.jpg[/img]

Exhaust duct: 

[img=325x400]http://i465.photobucket.com/albums/...ads/IMG_20161016_155711_zpsegwjwzkk.jpg[/img]

[img=450x375]http://i465.photobucket.com/albums/...ads/IMG_20161016_155734_zpsdbwne5iu.jpg[/img]

 

[rvpopeye]

We're gonna have to nickname you Rube Goldberg

 

[BradKW]

We're gonna have to nickname you Rube Goldberg

Yeah, wait till you see how it also ventilates the bathroom on demand. Still trying to come up with a way to tie the hood system in...  

 

[SternWake]

Is the vent above the wheels before or after the wheels?

If in front of, it might be a high pressure area , fighting the fan flow when driving. Perhaps a way to close it off when underway, Check valve?

My van has the mushroom vent uptop, and if the front windows are closed and van is moving, every other air possible air entrance is flowing toward my roof vent whose diameter is only 4 inches.

If yours is similar, all the air rushing out the Maxaair vent might be replaced through your fridge/ AC exhaust, in reverse

 

[BradKW]

Well, the intake is through wood floor just inside of wheel well, while the exhaust is actually through the metal well...so it's 5" higher.

But this is a closed system, or it will be, so I'm not sure what you're picturing. But fair to say, if I'm driving I likely won't be running the back AC anyway, as the truck AC is very strong...

 

[BradKW]

Didn't get to spend much time working on the build this weekend, had lotta misc. crap to take care of. Sternwake yelled at me and made me charge my batteries, so I did...it was a good idea. Learned a few little things along the way...and my found my new hydrometer delivered when I got home. That's for next week.

[img=300x400]http://i465.photobucket.com/albums/...ads/IMG_20161023_111026_zpsm1gobvz6.jpg[/img]

Did a dry fit of the 'fridge and decided it's better to be lucky than good...the side insulation in cabinet is so exact that it rubs while pushing it back. The top is a combination of too tight and not enough room...so I invented something!

I will call this a "Elastomeric Hinged Foam Compression Insulating Flange"... or EHFCIF for all the acronym lovers out there.

Basically I wanted a tight seal to top of fridge in back, but couldn't get it exact enough without running likely risk of it hitting when trying to install fridge. So I sliced some rigid foam to get thickness right and glued in some 1" soft foam I had around..came with AC I think:

[img=400x300]http://i465.photobucket.com/albums/...ads/IMG_20161023_130513_zpsvub5uytc.jpg[/img]

Then glued another piece to it, caulked where "hinge" would be...and the foam compresses as fridge slides under it to keep a tight fit:

[img=440x300]http://i465.photobucket.com/albums/...ads/IMG_20161023_132404_zpsss5gj0yu.jpg[/img]

Next week I might use Sikaflex, foam board, and wax paper to create custom fit, perfectly sized gasket panels  

 

[SternWake]

Nice. Well done.

My fridge is so tight a fit in my cabinet there is a whooshing sound when In inserting or removing it into/ from its insulated receptacle in my cabinet.

I had 3 panels on the top and sides of foam board which i was taking 1/32 inch passes off of with my power planer and test fitting after each pass until it actually slid into place without excessive force.

 

[Matlock]

Good to hear you got a charger on those batteries.
I like the soft foam insert application for a snug fit on the insulation. I hear a lot about rigid foam squeaking (no pun) and I haven't experienced it but if it was going to squeak it just might with that window shaker. Now with the soft foam addition I could believe that a possible nonexistent problem has been corrected. And the wax paper, well, just good ol MacGuyvering in my book.

 

[tx2sturgis]

I know its way too late now, but I would have used in-line HVAC duct boosters.

AC powered, (which you will have plenty of), and you can get them with thermostats for auto on-off, they use quiet induction motors, and they run almost silently, while sipping just a few electrons:

There are round ones, square ones, big ones, small ones, cheap ones, expensive ones...on and on...


https://www.amazon.com/duct-fan-booster/s?ie=UTF8&page=1&rh=i:aps,k:duct fan booster