Ultra-light Expedition Trailer

Before I begin, a couple caveats.

1) After several years of reading them, this is my VERY first time writing a thread so sorry if you cringe over my novice-ness, if that’s a thing.

2) I initially built this trailer a couple years ago so this is all coming from memory and old photos.

My goals for the trailer began simple enough. It must be ultra-light and compact for towing on long distance road trips behind my 2002 Volkswagen Jetta TDi. I was also looking for a project to build with my hands, which is an eloquent way of putting: it needed to be in my price range.
After scouring the interwebs for ideas, the original one being a tiny pop up or teardrop, I stumbled across the world of “Expedition Trailers”. How fantastic!, I thought. Tiny trailers with a rooftop tent, perfect. So the brainstorming began. Serendipitously, I had also begun dabbling in Google Sketchup, a free, uber simplified 3D CAD program. Spending the winter in rural eastern Kentucky, I had plenty of time to play around and sketch my trailer idea. I highly suggest checking the program out to anyone interested, and would be happy to email my actual file for this trailer. It can be viewed in 3D, along with a tape measurer function to see all the dimensions. Here are some screenshots.

This expedition trailer began life as a 4x6 tilting utility trailer purchased off Craigslist…. Here is also a good place to say that basically everything in/on/under this trailer came from Craigslist. It’s an incredible source for people who have too much stuff and willing to sell dirt cheap IF you live near the right cities. (I’m looking at you, Denver CO.) The reason for the rest of the raw materials usually had more to do with what I at my disposal/friend’s stashes/etc.
These photos aren’t from the original build, but after I blew it apart to repaint, and make a few tweaks. The prior work included: cutting off the low side bars and welding a “skeleton” of 1” square tubing. The tailgate is made from ¾” ABX plywood wrapped in a thin sheet of stainless on the exterior. I covered the expanded metal floor with a sheet of thin plywood that I treated in many coats of linseed oil to make waterproof, yet be super light. The sides were made from a couple 4x8 sheets of plastic (Can’t recall what kind, exactly). It’s flexible as not to break, and the lightest option I could find. Pretty cheap stuff. Doesn’t hold paint that great, but I haven’t heard any snickering yet from the woodland creatures over scuff marks.

(Roof) Top to bottom:

The rooftop tent is made by Mombasa, and is a million star hotel compared to the Ozark Trail tents I’m accustomed to. I have weathered at least one all night rain sesh in it, with zero leaks! The new price tag of $1k made me skeptical, but after purchasing one from CL (at a much, much lower price), I get it, they’re amazing. I went with a piano hinge as the mount for the tent, along with two junkyard sourced air lift supports. A 12v LED strip light on the bottom of the tent serves as illumination for night time scavenging of camp gear. The tent’s folded dimension is 4x4, leaving a 2’x4’ compartment on the front for easy access. This lid is made from the same ¾ plywood as the tailgate, with the top wrapped in aluminum diamond plate. I’m still looking for a better way to make the seal for this lid. When closed it, along with the tent, are sealed with a roll of foam padding. It’s pretty dustproof, and the tent overhangs slightly so its compartment stays quite dry. The metal lid makes great countertop space, but moving everything off to lift it was a pain. One day while staring at the thing for hours it hit me to use the same pin that locks the front as a point to flip it around and make the countertop usable while still being able to get inside goodies. I hinged a piece of 1” tubing to the back, which becomes the front, so it would rest on the tongue to provide support. Two pieces as a triangle would work better, but hey, that involves algebra and twice the tubing. Resting on the tongue rather than the ground solves the uneven terrain issue.

Electrical system:

Here comes the fun part, electricity, better known as magic. For the most part, this trailer’s system is all straight forward. Two 12V car batteries because I had them. Deep cycle will come when the funds do, as I spent it on things I didn’t already have. Kept the system 12v to make powering common things easy. I mounted a simple triple “cigarette lighter” plug. I also added a 1000w inverter for A/C power, though I find I never use it as it is less efficient due to the loss of conversion among other things (running the inverter fan, etc). Thanks to my master electrician father, who’d definitely frown on me for not wiring it better, I had the idea to add a GFCI outlet on each side of the exterior, wired with 14-guage NM-B wiring (UF would have been proper, sorry Dad) to the inverter. I hard wired a spare battery charger to the system; shoving it and the batteries into a Rubbermaid tote that lives in the front compartment due to that space being less waterproof than the rear 4’x4’ compartment. The cord for the trickle charger was routed to the tongue. Obviously, the point is to be away from shore power, so part two of the charging system came from a lucky find off CL, imagine that. While searching for solar panels I ran across a (China special) 200w kit. It included two 100w panels, hinged together, with one leg on each for support, and a cheap charge controller. It has buttons, a bunch of Chinese letters, and luckily some illustrations to indicate what all the wires go to. It even came with 20’ of 14g pos/neg wire. The whole kit for an incredible $100! The catch? The glass had shattered in shipping. I quickly snagged the deal, knowing even $1/watt was a deal just for a panel much less the other stuff. A friend suggested rather than replacing the glass, to simply use two part clear pour-on epoxy often used on bars and other high traffic counter tops. Luckily, the panels weren’t moved much and in the original package so the glass shattered but still there. The epoxy would (and did) seep into all the cracks, essentially sealing and “gluing” the glass in place. Epoxy cost: $26 from Amazon. “Envirotex Lite” brand I believe. Well, so far so good I can report. On a sunny day the panel outputs roughly 21v @ 8.0a. The lost ~1.5a (the kit is rated at 9.5a) is likely due to the cheapness panel. Either way, it’s much more than my current needs.

Part 2

The “Fridge”:

Now to possibly my favorite piece of the system, the “fridge”. I was inspired by a book called Off on Our Own by Ted Carns (off grid living, so far I’m still just a dreamer of it). It went into great detail about Peltier crystals, a/k/a the magic bar with two wires extruding that exchanges heat from one side to another when supplied DC current, and actually PRODUCES electricity when heat is applied, but that’s another tangent. They are commonly found in those 12v DC “iceless” coolers sold by Igloo or Coleman. The problem I had was the cooler size was either much too small (12qt), or too tall (40qt) for my trailer. So, having found a 12qt iceless cooler for $20 on CL, I also purchased a 52qt marine cooler by Coleman and decided to play Franken-cooler. Step one, remove lids. Step two, dismantle iceless cooler to find out how its magic works. Easy stuff really, one fan motor, two blades connected by the same shaft. One inside and one out, each blowing air across an aluminum fin heat exchanger that sandwiches the Peltier crystal piece. I cut away the unnecessary bits, using some 1/8 wood paneling as an inner plate mount. Once everything was in place, I filled the voids with MINIMALLY expanding foam. Minimal because the maximum is powerful and I worried it would blow out my lid. As a side note, I drilled several tiny holes in the hollow side walls and filled them with the rest of the can. I now call it Squatch, a/k/a redneck Yeti. Many specs on these coolers eluded my Google attempts, but I managed to find a couple sources claiming they require 50w of power (12v x 4a). ¼ day of good sunlight replenishes that. So far the “fridge” works well enough, about 40’ colder than the outside temp.

The Kitchen area:

Not much to put here, though future plans are big. As of today, the kitchen is mainly a Rubbermaid tote full of utensils, pans, etc. Our stove is an oldschool white fuel Coleman 2 burner, that I love because it reminds me of camping as a kid. It even leaks occasionally and catches fire like in the old days. Thanks again Dad, this time for the selective words needed in conjunction with the many quick towel slaps that put the flames out. I also recently scored a plastic table for added counter space. I splurged on one from Tractor Supply (search fish fileting table) that comes with a built in sink. Just hook a garden hose to the underside, place a bucket under the hole, and viola. It goes great with the water system I don’t have yet…. I would love to drop a thousand bucks on a legit Drifta Kitchen, but I’m far too cheap for that, so the next best thing is to build my own. I again turned to Google Sketchup for designing the pull out kitchen. The best part is getting the dimensions right virtually first, seeing as I’m no carpenter, not even close. I modeled mine very close to Drifta, making sure that it fits into my trailer, and the spot for the stove fits my current model with ease. I plan to use the plastic table with sink as the “return”. I’m assuming everyone reading this is familiar with the Australian company, Drifa. If not, ask Google and watch their YouTube videos, but put a helmet on first as your mind will most likely explode, or at least mine did. Hoping to turn my virtual sketch into reality this winter with some downtime.

Other Odds-n-Ends:

When towed behind the tow vehicle, I noticed the trailer lurched forward and needed to be lowered some. Luckily, its suspension is the basic solid axle bolted under leafs. So, I pulled the classic HS customizing trick of flipping the axle so the leafs sit under the axle, effectively lowering it exactly the width of said axle. Took about 30min and lowered the height roughly 2”. The result looks like the trailer was built for the height of the car (which has a 2” lift kit, but I’ll save that for a tow rig thread). Having gone through 2 sets of the tiny tires, I am looking for suggestions on new wheel sizes. Unlike most on this forum, I do no major offroading with my trailer. Even with the trailer, I can manage 41mpgs per tank @ 60mph (without the trailer my personal record is 60.1mpgs). I say that to further explain the like/need for skinny tires, less drag. Our very first test roadtrip with the car went from western KS, thru Utah to southern CA, up HWY 1, back towards Yellowstone, and returned to KS for a total of 4000mi, so every MPG counts. Does anyone make a high mileage tire in 5.30x12?
I also have been trying to come up with some future plans for an awning over the kitchen area. One seemingly ambitious (and by that I mean to say it has a high probability of foolhardiness) came to me when watching friend, and fellow Expedition Portal member mse871859949 build a hard-sided trailer with a truck bed topper as the roof. Mini truck toppers come in 4x6 (so it’ll lay flat like a turtle shell over my trailer), aluminum ones are fairly light, and it could offer the option for an extra roof rack. Again, I returned to Google Sketchup for designing. A great feature of this program is that so many people have already done the hard work of creating many common items. The 4x6 trailer platform was one, along with my tow vehicle (MAJOR kudos to the person who figured out enough to make a whole car with proper dimensions), and in this case I also found a truck topper to use/mod. My basic idea (not that there’s a more elaborate one, the whole thing is basic) is to use 1” square tube to connect the front of the topper with the rear of the trailer, hinges at both connections. It can be lifted up and back while two rear legs drop off the back of the “awning”. Seems simple enough, and one day I’ll be able to write a follow up on why it’s not simple, or enough…. Once the awning is real and functioning, the options are endless really. From adding canvas walls for an enclosed room to adding a water tank on top for pressurized water. OK I admit that wouldn’t work for more than anything over, say 5gal due to having to lift the heavy thing up when setting up the awning. It would be feasible to build a solar hot water “heater” from some 4 or 5” black PVC pipe mounted on the roof. Same principal as those hot water bags. I told you I was a dreamer :).



Expedition Leader
Lots of good ideas implemented here, and love the "Squatch" part! To maximize the cooler you can still use frozen bottles of water and add a thermo switch that will turn the fan on or off depending on internal temperature. I thought up a similar design a few years back that would use 2 of the thermoelectric cooling fan setups on one cooler but the amp draw killed the idea real fast.


Expedition Leader
Same idea Im thinking of building for my dad so he can do trips in his G35x. His old Explorer/Xploder has 260,000 miles on it and is restricted to intown only use these days ;-) looking at finding a PWC trailer $400 target, then building off that.


Expedition Leader
Whats the box depth? Are you happy with that depth vs gear stowage options? Thats the one big measument I'm still trying to sort out. Needs to have enough height to stow gear but not too high its creating extra drag with the tent sitting up high. Etc
Calicamper: The storage is 1 1/2' tall, just big enough to fit a standard rubbermaid tote, which is what I primarily use for organization. In hindsight, I wish I would have made it tall enough to accept a Drifta Kitchen (430mm height), and tall enough to accept a 40qt iceless cooler by coleman or igloo. Those were too tall, hence the reason for building my own. That said, the top of the tent sits just right behind the mk4 Jetta. I'm big into MPGs and aerodynamics were a concern. Best of luck on your build!!

Thanks for the idea, Jeep-n-montero, iceless coolers like the one I cannibalized aren't the most powerful, and frozen water bottles would help. Also try to only put pre-chilled things in it. I highly suggest filling any cooler walls with expanding foam (minimally expanding to prevent a blowout, "Great stuff" is the brand i used) Most cheap coolers have hollow walls. The idea isn't original to me, but I've found it really helps cheap coolers be more like expensive ones.
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