Pro-Rig V2.0 - Home Built Compact Composite Pop-up

[CoyoteThistle]

I did consider doing fiberglass around the outside corners but judged it to be too much messy work. To do it right, you really need to round the edge (router probably) and then fill the "end grain" of the exposed honeycomb core with thickened epoxy, then sand it all smooth, then apply the fiberglass, then sand/fill to make it smooth. I did this on a few corners inside the camper and it was indeed a pain compared to just doing the aluminum angle. Using foam core panels would make this a couple steps easier.

Fiberglass would likely be stronger than the aluminum angle and would look better (if done carefully). Aluminum gives some extra protection against impacts from branches maybe, but that's the only real advantage other than being a little less work.

 

[CoyoteThistle]

Did some cold weather testing/skiing last weekend up in the Mammoth area. Skiing was great, lots of powder and avoided the crowds. Good stuff.

New ski racks worked well but they call this a three-pairs-of-skis size


Got two in but don't think a third would go. Hmm. Tips just clear the camper. That part is great.

After a day on the slopes I wandered out to the hot springs, thinking all the fresh snow would keep folks out.


No such luck. It was slippery driving and eventually met up with some kids in a Subaru that were stuck and blocking the road. Spent an hour plus with several other folks trying to rescue them. We all got out, another dudes MaxTrax saved the day. Time to buy some of those I think. Didn't get to soak

Cold weather testing was a mixed bag. Trying to figure ways of dealing with the water system in low temps - had a minus 9*F morning with daytime highs probably under 20*F. I left the water pump off and faucet open and drained the hot water heater, hoping as things froze the expansion wouldn't destroy things. All the lines froze. They thawed a bit on the drive home Monday night and and as I looked in to the cabinets where all the hoses and tanks are, there was water everywhere. Crap. Lines were still mostly frozen so I let it sit overnight. In the morning I sopped up about a pint of water and dried it all out with fans and a space heater. Crazy thing is, the whole system seems to be fine still. No leaks. Hot water heater still working fine.

No real clue as to where the water came from. I think I need a better plan for cold temps though. What do folks do?

Heading up the coast this weekend for an overnighter, with Sheri this time - stoked to be getting out and using the camper!!

 

[java]

Keep the heat higher inside? I have one live that will freeze, across the crawl thru area, but the rest stays unfrozen.

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[Xrunner]

No real clue as to where the water came from. I think I need a better plan for cold temps though. What do folks do?

Heat tape on its own switch, maybe?

 

[CoyoteThistle]

Heat tape on a it's own switch, maybe?

I bought a little strip of heat tape a while back to experiment with. Seems daunting to do the whole system and current draw might add up for my battery-only system. Think I'll use the small bit I have on or near the pump to protect it from damage.

Keep the heat higher inside? I have one live that will freeze, across the crawl thru area, but the rest stays unfrozen.

Do people do this? Leave the heater on while away during the day? Guess I'm paranoid something would go wrong while away. Maybe that's silly since I sleep with the thing on. This would be a simple way to go.

 

[java]

I bought a little strip of heat tape a while back to experiment with. Seems daunting to do the whole system and current draw might add up for my battery-only system. Think I'll use the small bit I have on or near the pump to protect it from damage.



Do people do this? Leave the heater on while away during the day? Guess I'm paranoid something would go wrong while away. Maybe that's silly since I sleep with the thing on. This would be a simple way to go.

I usually leave mine set to 40 when I am out skiing.

 

[CoyoteThistle]

Couple updates...

Coldish/wet weather testing a couple weeks ago at Mammoth/June revealed a new issue. I did a couple nights of parking lot camping at the latter resort, it was right around freezing and snowing hard (wet snow). With all my wet ski clothes hanging to dry


and just myself hanging out all evening (pop-up in down position), there was an alarming amount of condensation. I had the heater going and cracked the window while cooking, but man did things get wet. Points where I have a bolt through the roof (only a few of these for the scissor lifters and roof hinges) were obvious problem points. I thought they were leaking but testing at home shows them to apparently be watertight. Eventually, the walls themselves on the slide-up were wet. Towels kept it reasonable and everything has dried out after returning home. Any tricks to fighting this? Would love to hear ideas!

In other news, yet another reason to love the Propex heater:


Gets the boots nice and toasty before slipping them on!

Spending a bit of time on the computer this last trip (work and WiFi in the parking lot) made me loathe the cheap cigarette lighter inverter I've been using. Next update, Pro-Rig goes AC...

 

[java]

Yep it gets wet! I leave one of our maxxfans on low all the time.... yes seems backwards to loose the heat, but it keeps the moisture down.

Cant wait to see what you do for AC!

 

[ITTOG]

Any metal going from outside to inside will always condense vapor if there is no thermal break.

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[Ark]

Condensation is a tough one! I worked under a PE for an HVAC contractor in Alaska for several years and we dealt with removing moisture quite a bit. Plus, both of us went camping in the cold a lot so we often talked about trying to keep our tents from dripping on us! Since you're not going to get rid of the source of moisture (you and any burning hydrocarbons like your stove) you can either get rid of the warm, moist air and replace it with cold, dry air from outside (will cost you a lot of energy) or you can remove the moisture from the air inside as you recirculate it (use a cold AC coil to pull moisture out of the air. also energy intensive). Commercial heating/cooling units usually do both.

You can shoot for the "exhausting moist air" strategy by doing what Java suggests and leaving a vent open in the top of the camper. Replace the warm, moist air that's escaping through the vent with outside air (cold generally = dry) Try to control the dry, outside air by heating it before it gets into the passenger compartment. This costs energy but it will keep things comfortable. This is what pretty much all commercial buildings do anyway so even though it doesn't seem intuitive, it's a pretty common strategy. If you don't bring air into the space in a controlled manner, it will come into the camper through leaks and make it feel drafty and cold. If you can choose, it's best to slightly pressurize the cabin with the intake fan. That way, a small amount of warm air will leak out through small gaps in the camper. If you try it the other way and turn on your vent fan to suck the moist air out of your camper, you'll pull a slight vacuum which suck cold air in around your windows and other gaps and make the whole thing feel drafty and cold.

Where does your propex pull from? If it just recirculates air, I suggest you also install an air intake for it from outside so that you can have it pull in dry air and heat the air up before it enters into the occupant space. Then open a vent in the ceiling just enough to equal the volume that the propex is pulling in. That should slightly pressurize your camper and cut down on the condensation a lot.

If you want to get really fancy, install a mixing valve on the propex heated air intake like your car does. Monitor the humidity with a hygrometer. When the humidity starts getting a little too high, open the vent and flip the propex to start pulling in outside air. When you bring the moisture back down to where you want it, close the exhaust vent and change the propex intake back to internal air.

You should also look at using a small fan to circulate air around inside of the space. If air stops moving, it can stagnate near the walls, cool down and then condensate on the walls. You'll basically get a stagnate layer of air right next to the walls that slowly gets colder as the walls loose heat. Eventually it will condensate. Moving air lets the warm air in the rest of the camper keep the camper walls warm enough that they won't drop below the dew point temperature.

Take a look at the arctic oven tents. They use this same strategy with a vent in the top of the tent and a small intake vent at the bottom of the tent. They don't have a fan option but try to heat the cold, dry, outside air with a wood stove. That whole system works passively with hot air rising out the top and cold, fresh air coming in the bottom. It does consume a fair amount of wood to keep going but those tents are a lot more comfortable when camping in the winter time than a traditional wall tent. The wall tents will start to frost up the walls and after a few days the ceiling will turn the whole thing into a frosty, miserable rainforest....

The other possible strategy for reducing condensation is to remove humidity from the air. You can do this using an AC unit or a dehumidifier. You basically condensate the humidity on a cold AC coil and then drain the liquid condensate outside. This also takes energy and adds complexity. Plus you still have to heat up the air a little bit to make up for the cooling effect from the cold coil. You also have to figure out how to drain the condensate without it freezing up. Commercial buildings also use this strategy to dehumidify. It does work! Just a little more complex.

 

[CoyoteThistle]

Yep it gets wet! I leave one of our maxxfans on low all the time.... yes seems backwards to loose the heat, but it keeps the moisture down.

Cant wait to see what you do for AC!

Makes me feel a little better that this is a challenging issue even in your big rig with good insulation. I don't currently have a roof vent/fan, but maybe I should start thinking about that. I always thought of them as a warm weather asset that I could do without due to the well-ventilated pop-up, hadn't been thinking winter.

Any metal going from outside to inside will always condense vapor if there is no thermal break.

Okay, so maybe a dumb question - are there options for non-metallic bolts? The ones on the lifters (1/4" IIRC) are pretty low torque since they go through the sandwich panel. I could probably eliminate them (lifters are bolted pretty securely to angle aluminum inside) but I guess I just like the extra connection to the slide-up.

Condensation is a tough one!

Where does your propex pull from? If it just recirculates air, I suggest you also install an air intake for it from outside so that you can have it pull in dry air and heat the air up before it enters into the occupant space. Then open a vent in the ceiling just enough to equal the volume that the propex is pulling in. That should slightly pressurize your camper and cut down on the condensation a lot.

You should also look at using a small fan to circulate air around inside of the space. If air stops moving, it can stagnate near the walls, cool down and then cause condensation. You'll basically get a layer of air right next to the walls that slowly gets colder as the walls loose heat. Eventually it will condensate. Moving air lets the warm air keep the camper walls warm enough that they won't drop below the dew point temperature.

Thanks for all your thoughts on this Ark, that was all really good info. Yeah, the Propex recirculates air inside. That's a really good idea though - adding an intake from the outside, maybe with a Y and some sort of valve to select recirculate or outside air. Time for some research on ducting.

I have a little USB fan, sounds like deploying that would be helpful.

What about the little dehumidifiers that use the silica gel beads? Are they of any use? I'm only at something like 200 cubic feet of volume and they claim to work on that scale.

 

[java]

I tried one of the "rechargeable" silica ones, no measurable difference.

I like the outside air intake idea!!

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[CoyoteThistle]

I think I have a plan for the new air intake for the heater, I think it will be easy. That will be a future post, for now, it's time for an inverter install report.



That's what I landed on, 350 watt Victron unit. I'm a fan of their stuff in general and this had some good features for me. Standby current draw is really low - manual says 3.1 watts, reviewer on Amazon measured it at 180mA (little over 2 watts). It has remote turn on ability so I can mount it in a hard to reach place and still turn it on with a remote switch. It's pure sine wave (which seems to be the way to go for laptops).

The install was pretty straightforward. I know almost nothing about 120v AC so did a little You Tubing on the wiring stuff and headed to the hardware store for some kit.

I decided to mount the inverter inside the refrigerator compartment. There was sufficient dead space in there and this means no loss of other storage space. A scrap of 3/4" ply, some aluminum angle, and some hollow wall rivets and it was in.


Wires at right are power - hooked through the spare breaker switch on my main switch panel (switched off at the panel, there is no standby current draw). Wires at left go to a remote turn-on switch. Three-prong AC plug goes to the outlets.

I wired up a small box with the outlet.


I added the little pieces of plywood on the sides to give it the 1-inch back spacing I need for my walls. AC wire is a cut-to-length appliance cord (three-pronged male end only thing). Mounted it like so:


I added screws through the side in to the plywood bits to secure it. The black square next to the outlets is a little toggle switch for the remote on/off. Should probably add some little labels to that. Not sure I like the look of the SS around the outlet, but we'll see how it goes.

Overall, for about $100 and no loss of storage space, I'm happy with having the option to power AC stuff now.

 

[CoyoteThistle]

Few little mods to report...

After looking at the way I installed the Propex heater, I realized setting up an outside intake would be easier than I thought - specifically, the intake just draws air from the space inside the cabinet through a register in the door of the cabinet (i.e., no intake duct).


This meant I could just draw from outside through a new register and plug one or the other depending on what intake source I wanted. I didn't feel confident in using the plastic register that Propex uses for the outside so I started looking for alternatives. As usual when looking for something that doesn't quite exist, I did the usual Amazon search and trip to the boat store with no good results. My third stop is usually the plumbing section at the hardware store - voila!


Yes, it's a shower drain. A 3.5" hole saw through the floor and cranked down a bit on the large nut.


Nice stainless steel on the outside with a good rubber gasket.


On the inside, it has a rubber seal meant to slide over a 2" pipe. I got a 2" pvc plug that fits nice and tight.


Some silicon sealant around the outside and it was a real quick project in the end.

Other little projects include a paper towel holder up high on the roof


Got it off Amazon, has a kind of ratchet system on the roller so it's not supposed to unroll while driving. So far so good, but off road testing to come.

Also excited about a little weather station (I'm nerdy that way).


Indoor and wireless outdoor temp and humidity.

Finally, some hooks on the roof for jackets and such.


Located it over the potty. This came in very handy on the ski trips lately.

Gonna go chase the superbloom out in the desert next week with the rest of the world - expect Pro-Rig will get us away from the crowds though

 

[wanderer-rrorc]

standing slow clap

You are doing an AMAZING JOB!!!!

As a 20 year journeyman plumber I am ALWAYS showing folks cool ways to re-purpose plumbing materials.

Cant wait to see how she's finished out!

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