Behemoth Rising - 40ft 5th Wheel Conversion

Midwestdrifter

Engineer In Residence
I like the ice chute! I do need to duct the condensate out of the compartment, otherwise it will fill with ice pretty quickly.
 

rollerbearing

Well-known member
Heh, heh - in the spirit of "off grid" - collect the condensate from your "water maker" and ............
 
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Midwestdrifter

Engineer In Residence
I suspect that any place humid enough to have substantial condensate would have significant rain, there are exceptions of course. Even if all three units were running, I doubt I would get more than half a gallon per hour. It would need significant filtration regardless.
 

Midwestdrifter

Engineer In Residence
The slide floor is glued up, and I applied a coat of penetrating epoxy for waterproofing. I will probably glue some "tarp" like material to the bottom, and wrap it over the edges to direct any water out.

Got the roof stripped today. Everything looks pretty original. Other than a few minor things, the factory did a good job I think. No major rot areas. I will be removing the sheating plywood with bigger holes, and replacing with new. I might as well remove the AC ducts, and add strigers between the struts at 1/3 width intervals. The primary truss spacing is 24", however wherever there is a roof vent or other penetration, the spacing is 16". Which makes for a few low spots between the 24" ones, as 3/8" OSB is not very stiff. There is one truss ahead of the center AC unit which seems a bit funky, so if its cracked I will sister with a plywood side brace.

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The front AC is ~8k BTU, the middle unit is the ducted unit, and its 13.5K, and the rear is 13.5K. That's 4kw of AC, which is borderline ridiculous. Probably necessary due to the poor efficiency and insulation, but ridiculous nonetheless.

Tomorrow I will replace/repair the decking and clean everything up. Hopefully Tuesday I can bond the new membrane down, and seal.
 

marklg

Well-known member
The front AC is ~8k BTU, the middle unit is the ducted unit, and its 13.5K, and the rear is 13.5K. That's 4kw of AC, which is borderline ridiculous. Probably necessary due to the poor efficiency and insulation, but ridiculous nonetheless.
I passed a behemoth on the road a few days ago with five air conditioners on the roof.

Regards,

Mark
 

Midwestdrifter

Engineer In Residence
I passed a behemoth on the road a few days ago with five air conditioners on the roof.
It has gotten a bit ridiculous really. Some units are over 20klbs on the dealer lot, you would think some of that weight could be put towards insulation. I guess RV/trailer owners have been convinced there isn't anything better.
 

Midwestdrifter

Engineer In Residence
Got the AC ODU today. Every bit as big as the spec sheet, though feels a but lighter? I may need to remove the generator compartment front wall to install. Thankfully its just a few bolts holding it on, and some trim.

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Making progress on the roof, still have 4 panels to replace. Ended up with 1/2" CDX. Though most of the sheets I found didn't really have a C, side, just two D rated ones... So I will need to mix up some filler for the low spots tomorrow. It is amazing how much stiffer the roof is with the plywood over the OSB, even though they are the same thickness. The plywood is lighter as well. In some random places they put 15" wide 1/2" OSB sheets between the joists, but on top of the thin ceiling panel. They aren't anchored to the joists, so they must just serve for mounting random crap, and adding weight without stiffness. I figure I can increase the stiffness by 50% without adding any weight.

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Still trying to figure out what we want for a water heater. Considering RV standard LP/electric. LP on demand style, or on demand with storage tank custom hybrid of some type. Finally some diesel/gasoline hydronic unit. Nothing is a clear winner at this point. Electric on demand is probably just too many watts when we plan to have 4-5kw induction cooktop.
 

Kajtek1

2015 3500 X long limo RV
For on demand electric shower heater you need about 15 KW, what depends on the coming temperatures, but it is still a lot.
The only place I have seen those used were Germany, where 2 bdrm condo had 50 kW electric panel.
On other hand I converted standard propane 5 gallons W/H to have "hot rod" electric element who is about 200W. When it takes long to recover, with thermostat set high and thermostatic valve in bathroom, it work very well and we can take 2 semi-long showers back to back.
Would you come on desert in 110F weather, 4 k BTU for big trailer is not much.
Prevost are well insulated from factory, yet 5 AC at 15k BTU are standard.
 

2021_3500_LowRoof

Well-known member
The P.E. I am referring to is (1.7 to 2lb.) is about R7 per inch, the same as closed cell urethane, a lot depends on how well you seal it, but that is also easier since it can have an interference fit. it has enough structure to help with flimsey wall panels, especially if you use some adhesive. The sound deadening is better than all the hard foams. I used some styrene and some iso in my bus and the styrene off gassed whenever it was hot out,
I wouldn't do that again!
My point on structure wasn't really about the actual metal trailer, more about the cheap build, like you said, water intrusion and other things like particle board cabinets and general cheap fast construction. Your low mileage usage sounds like a good fit.
You may even profit when you sell it if this trend keeps up!
Sounds like you did well on the initial purchase too. A friend of mine bought a trailer park in NM and has run into some deals. It seems like good deals on 5th wheels turn up regularly. He bought a 10 year old 35ft. rig with a screwed up slider for $2500. it was in great condition except for the slider (water intrusion) which only took 2 days to fix.
As far as stupid names for trailers are concerned, see the pic below!
Why does that trailer seem incredibly close to the truck?
 

3Play

Well-known member
Still trying to figure out what we want for a water heater. Considering RV standard LP/electric. LP on demand style said:
The on demand ecotemp propane H20 heaters work great, I have had one on my off grid bldg. of 10 years. They are only about $140 for the camp version. I would get the next one up because the base model mixes cold water, so you can use it with a single supply as a shower.
One of the sprinters I went to Mx in had a similar model. They are very efficient...
 

Midwestdrifter

Engineer In Residence
I am looking at the LPG on demand units. I would probably like to avoid LPG, as its freaking expensive lately, but that is a quick option. I have a location for a side vent, so I will probably do something with a power vent option, if I go that way.

A 6 gallon electric unit with 1-1.5kw element is also an option, as the recovery time should be reasonable. Set that to about 180F, and use a tempering valve to maximize storage. Could have an LPG model as well for very fast recovery.

Got the roof deck finished today. Need to close up the radius, clean up the trim, and check for sharp edges, and transitions. Then is membrane time.
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rollerbearing

Well-known member
A 6 gallon electric unit with 1-1.5kw element is also an option, as the recovery time should be reasonable. Set that to about 180F, and use a tempering valve to maximize storage. Could have an LPG model as well for very fast recovery.
You can get a combination 6 gallon electric & LPG RV hot water heater. We often run the electric element AND the burner to shorten recovery times when the whole family is taking turns showering. You wouldn't be able to do it in all scenarios - but when you can/need to it's really nice. The RV water heaters tend to run pretty hot - if you've got enough capacity you can turn the temp down with an add on thermostat.


These are crazy expensive - but I have always thought they would make good sense in a shower drain line where you can continuously preheat the incoming cold water to the faucet. Maybe a cheap DIY model could be rigged up.

 
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Midwestdrifter

Engineer In Residence
You can get a combination 6 gallon electric & LPG RV hot water heater. We often run the electric element AND the burner to shorten recovery times when the whole family is taking turns showering. You wouldn't be able to do it in all scenarios - but when you can/need to it's really nice. The RV water heaters tend to run pretty hot - if you've got enough capacity you can turn the temp down with an add on thermostat.
Yeah, the current unit is 750W with LPG burner. We could do the same for not crazy money. I just hate how low the LPG efficiency is.


These are crazy expensive - but I have always thought they would make good sense in a shower drain line where you can continuously preheat the incoming cold water to the faucet. Maybe a cheap DIY model could be rigged up.
I was noodling a heat recovery system the other day. With a modest length shower they do recover a fair bit of energy. So the question is. could I do something similar with aluminum tubing and some heat sink compound? Might be doable. 70$ for a 2" AL or copper pipe, lets say 24" long. Then 20ft of 1/2" copper or aluminum tubing, wrapped around. Might need 2 or 3 parallel tubes to avoid flow reduction. Probably about 200$ in materials.
 
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hilld

Well-known member
I’ve done 4 LG Multi systems and here’s what I’ve learned:

Flare your ends with the Spin Tools kit. Hard to believe but it makes great flares. In about 15 seconds. I have the (more expensive) Yellow Jacket tool but much prefer the Spin now.

Do not buy individual line sets, rather buy one line set that covers your total length.

Figure out your lineset lengths. Then order the durable white insulated (not black foam) line sets, based on how many feet you need. And- now they have “duplex” line sets- 1/4” and 3/8” paired together, makes it twice as fast ? Love em!

Run the first line set and cut it to length. Then repeat for the other line sets. Do the same for the electrical connecting cables.

Don’t buy any flare nuts. They‘re included on the LG evaporators. They come nitrogen charged (you’ll hear it escape when you take them off). The flare nuts are sealed with nylon or copper blanking inserts; remove the inserts and you’re ready to put them on the line sets. The LG flare nuts are very high quality, much better than the ones preflared on the line set you buy.

Don‘t worry about kinking the line sets, just use common sense and bend them by hand. The ones coming out of the evaporators are scarier as the copper is stiffer. But still, you won’t kink those.

Label room names on line sets and corresponding connecting electrical cables. Verrrry strange results if 2 room’s connecting cables are mixed. Don’t ask me how I know that…

Don’t worry about having too much r410a in the system. LG manuals from 4 years ago were very specific about removing refrigerant if line set lengths were shorter than a certain length. Subsequently they have removed that text, much to my chagrin. On my first install so as to not have to remove refrigerant, some of the line sets are longer than I would have liked. It’s on my “to do” list to shorten those up.

Unless you have the proper open jaw torque wrench, use common sense when tightening flare nuts. But do tighten them a lot. Use Nylog Blue on all joints.

Pull the Shrader valve core with the Appion tool. Nitrogen pressure test overnight.

Vacuum to below 500 micron, valve off vacuum pump, vacuum test for a few hours to observe no significant rise.

Put the valve core back in and cap off (use Nylog on those caps too)

Release the beast and see how it works.

BTW the LG condenser is louder in heating mode compared to cooling mode.

Smarthinq is pretty lame, but handy none the less. Do the diagnostic test for fun. My son has Home Smart (sp) and controls his LG minisplits (and many other Arduino devices) with that.

Home Depot has gutter that makes great single lineset cover. Just rip a 1x4 a little, screw it on the wall and attach some fasteners to cable tie the line sets, electrical cable, and drain line too. Then attach the gutter over it all with some stainless panhead wood screws into the sides of the 1x4.

Here’s some links that may be handy:








I‘m a fan of what you’re doing with this ”Medium” Home idea. That12’ attached garage should be great for a workshop. Where do you envision parking it when you live in various cities- rent (or buy?) land, rather than campgrounds?

Stay happy!
Roy
The link for the Spin tool you posted is for the swaging, not flaring.....was that intended that way?
 

Franny

2005 T1N 158
The link for the Spin tool you posted is for the swaging, not flaring.....was that intended that way?
Sorry, thanks for pointing out my error! NOT the swaging set (s), but rather the flaring set (f).
MD mentioned that he bought a similar flaring set; hopefully it works well.
 

Midwestdrifter

Engineer In Residence
Had a bit of a rainy day, so I am researching a few solar panel options. It will be a year or more before I tackle PV, but I need to prepare a bit by adding braces to the underside of the roof skin. Since I will have the ceiling panels down for replacement or wiring/insulation updates, it seems like an opportune time. Looks like there are numerous panel offering around 18-20w/ft^2. So the big factor is how many can I tetris onto the roof. I need to leave a space to walk down, at least 12" wide. I would also like to make the panels tiltable. So panel placement needs to be such that I can park with one side of the trailer facing south, and have the panels not shade each other when tilted. So it will probably be such that each row (if more than one panel) will be tied together and tilt as a unit. Which does present some wind issues, as a 6ft combined length is significant. I might need to engineer a spoiler, or switch to only only tilting the northermost panel in each row.

PanelMPNWidthLengthwattsWatts/ft^2cellsPricePrice/wattRoof CapacityRoof WattsTotal CostweightTotal Weight
Panasonic HIT 330WHIT N330
41.5​
62.5​
330​
18​
96​
$ 334$ 1.01
12​
3960​
$ 4,008
41​
492​
Panasonic 370WEVPV370
40​
67.8​
370​
20​
60​
$ 438$ 1.18
10​
3700​
$ 4,380
43​
430​
Q CELLS DUO 340WQ.PEAKDUOBLKG6+AC
40.6​
68.5​
340​
18​
60​
$ 358$ 1.05
10​
3400​
$ 3,580
47.2​
472​
Trina 410WTSM-410-DE15
39.21​
79.33​
410​
19​
77​
$ 253$ 0.62
10​
4100​
$ 2,530
48.5​
485​

Here is a sample layout. With the Panasonic 330W units. Looks like braces between trusses at 1/3 width intervals should be fine. I can find those through the roof deck with my stud finder when I need to anchor the brackets. I will probably add a stringer most of the length of the RV on each wall, tying the trusses to the wall. Uplift wind forces are not to be trifled with. Some rough math shows about 40lb/ft^2, with each panel at around 18sqft, that's 720lb per panel, or 8,600lbs total. That assumes worst case loading direct, straight line winds over 95mph, and the panels all tilted over 25 degrees. I am pretty sure that much loading puts the trailer in danger of rollover though. So the panels need to go flat if a big storm is coming. That being said, I still need to choose fasteners and anchor points which can handle 300lb per panel of uplift.


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hilld

Well-known member
Have you looked at the Solaria XT400 panels, I purchased on for my van for about 370, less than a buck a watt. The have 2 different sizes for the same wattage so perhaps that can help with your game of panel tetris.

 

Midwestdrifter

Engineer In Residence
Have you looked at the Solaria XT400 panels, I purchased on for my van for about 370, less than a buck a watt. The have 2 different sizes for the same wattage so perhaps that can help with your game of panel tetris.

I do see them at a couple retailers. Small order prices are pretty rarely below 1$ a watt right now, but there are a few options in the 0.60-.90 range if I don't mind a 12 year warranty vs 25. It may come down to what my local distributor has when we go to buy.

The most important factor at this point, is just making sure I can safely mount them. It looks like I can get over 3.5kw, which drives a bunch of other decisions. Mostly that I am going to ditch LPG, and I will hold off on a gasoline/diesel hydronic system until absolutely necessary (maybe never?).
 

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