Grandby Shell Build

Hi All,

I wanted to share my progress on a Grandby shell build project I recently started. This forum has been invaluable as I've planned the build. I welcome any thoughts and comments.

I bought the shell this summer along with the 2017 F-350 it was attached to. In hindsight, this seems to be how the combined anxieties of a global pandemic, economic uncertainty, social unrest, and political divisiveness manifested. (In that sense, I guess I could have made a much worse decision.) My wife and I are rock climbers and backcountry skiers and over the years have had many different mobile camping modalities. We've lived in a Eurovan, had crappy slide-ins, slept in numerous vehicles, and have done plenty of tent camping. I'm convinced that there's no perfect solution, but the FourWheel camper certainly ticks a lot of boxes of us. Building it myself gives me the chance to customize it for our specific needs.

Hope you enjoy!
Brian

The bones:

The shell was basic with a couple notable exceptions.

1) An Espar heater tapped into the truck's 48 Ga diesel tank. The original owner went through the trouble of having this professionally installed which included taking the truck bed off. This think works like a champ and I'm happy there's no propane in the camper.

2) A 100 Amp hour LiFePO4 battery with BCDC charge controller and Vitron battery monitor. Another solid addition by the previous owner. Since I'm planning a really simple build, it's entirely possible that this will be plenty for everything in the camper. And, the BCDC controller tapped straight to one of the truck's 2 25 amp alternators means a completely dead battery will charge in just 4 hours.

3) "Solar-ready" There are plugs on the roof and rear to accept solar if we ever add this in the future. I'll wait for some data to decide if we need this, but it's nice to know it'll be an easy upgrade if we go in that direction.

This isn't much, but it's exactly what I would have done had I known enough to do them. These additions by the previous owner are really solid additions to build on.

-B

The design:

We had a few design criteria to work with.

1) It had to be very utilitarian to handle 4 seasons with multiple sports (climbing and skiing). Our default is function over form.
2) Lots of "open storage." By this I mean that we plan to utilize modular storage with removable plastic bins. This works for us because we are often switching between sports with different gear needs for each. We've found that being able to rotate these in and out is efficient and convenient. Also, I always thought it was strange when packing in previous campers how I would pack gear/clothes/etc in the house, carry it to the camper just to repack it in a cupboard. This way, I pack a bin in the house and put the whole thing in it's place in the camper. We also have big clunky climbing packs that need a space so they're not getting tossed around.
3) A quality DC fridge. We knew this was likely to be the most expensive feature, but one that was non-negotiable for us.
4) The ability to sleep with the top down in a pinch. Commando camping is occasionally necessary and it's nice to have a guest bed.
5) Simple water system, no water heater. I'm going with removable water containers under the bench with a small pump and faucet. No drain to the outside or hose fill option. We never stay at campgrounds with this option and are usually using public faucets or grocery stores to fill water.
6) "Lounge" space. We often find ourselves camping in groups we're climbing with. Although we're usually outside, when the wind's howling or weather rolls in everyone crams into the campers. (We climbers can be a delicate bunch.) Thus we wanted lots of seating that could also serve as a "warming hut" during ski season.
7) Simple kitchen. We'll be cooking outside, usually in a group, whenever possible so didn't feel the need to have a permanent stove in the camper. In a pinch, we'll just use a single burner propane stove inside to make a simple meal or coffee. This also avoids having a permanent propane tank too.

All of this is subject to change with time, and probably will. It is a very modular design so I don't feel too stuck with any of the decisions I've made and can always pull out elements and reconfigure as the need arises.

Items not pictured are the sink, a Lagun rotating table, and a counter top extension that's removable.

-B




PS - the design was done using SketchUp and I'm happy to share the files with anyone who is interested.

The bench.

This would function as a lounge space, guest bed, and sleeping with top down when necessary. I did this first before our inaugural road trip this fall so we at least had somewhere to sit. Underneath serves as part of the "open storage" idea and will eventually be where water containers are stored as well. It folds to half it's width and utilizes the cushions provided for the over cab bed slide out. I'll make some more cushions for this at some point. When folded, the cut pattern recesses into the side rails which acts to keep it from sliding when traveling (kind of lego-like). This first pass has some issues (it's too tall to comfortably put your feet on the floor for starters), but I have a plan to address these in the future.

-B

Cupboards.

This was my first foray into anything resembling finish carpentry. I built these out of 3/4 baltic birch ply, which I laminated and edge banded. I wanted a bright color to counter the drab gray that FourWheel has by default. I built them outside the camper in modular fashion. This was easier for me and will make it simple to swap out in the future if I change my mind. The first one on the passenger side will hold two removable storage containers and have one drawer. The bottom drawer is more narrow in order to accommodate the window crank mechanism.

I mounted these by directly drilling to the plywood base. I will also attach them to studs in the sidewalls with rivets that are tapped that I'll be borrowing from a friend. With the inevitable flexing of the camper while traveling, I think this is a much better way to go than using simple sheet metal screws. There will be a counter on this eventually and I'll probably have to add a bit of elastic cord to keep the bins in while going down rough roads.

- B

The "kitchen."

The fridge box was simple to build but took some thought for air circulation for the compressor. Normal folks would just cut a hole in their camper with a louvered vent to the outside. I wanted to avoid this option if possible for two reasons. First is that this could be a problem when winter camping. Second is advice from a friend who warned that allows a lot of dust to get in the camper. Since we spend a lot of time on dirt roads in the desert, this would eventually be a problem for us too.

So my solution was to design airflow into the cabinet carcass that would allow cold air from the bottom to circulate up and behind the fridge and out the top. I'll have two small DC fans on a temperature switch to help facilitate. I'll have more details on this once I wire it up and install it. As with everything I'm doing, it is all subject to change once I get some data on whether or not it actually works as intended.

The kitchen cabinet carcass will eventually have two drawers on the left and a door on the right where the sink will go. Oh, and a counter top.

-B

BSMSbuddy said:

2) A 100 Amp hour LiFePO4 battery with BCDC charge controller and Vitron battery monitor. Another solid addition by the previous owner. Since I'm planning a really simple build, it's entirely possible that this will be plenty for everything in the camper. And, the BCDC controller tapped straight to one of the truck's 2 25 amp alternators means a completely dead battery will charge in just 4 hours.

Click to expand...

Looks like a great setup. I do have to wonder why the charger was connected directly to the alternator. These DCDC (BCDC) chargers don't care about amps, only volts. They need a certain voltage min and max to operate and regulate the charge. Modern day trucks have smart alternators as part of their fuel efficiency scheme and these alternators monitor battery voltage as well as other power needs via the truck's computer modules. I don't believe the alternator is going to "see" your charger and there could be times when the alternator will throttle back dropping voltage below the charger's min requirement and causing the charger to cut out. Connecting directly to the battery eliminates these potential concerns. I don't know which charger you have but this is how my Victron Orion-Tr Smart (30amp) would work.

Take a look at this Redarc article. https://www.redarc.com.au/alternator-vs-fixed-alternator


Happy Trails
Dean

Hey Dean,

Thanks for the article; that all makes sense. I was definitely incorrect in my description and the charger is indeed connected to the battery and not the alternator. (I hadn't even heard of a BCDC controller before the seller described it to me.) Based on your article, my back-of-the-envelope calculation for charge time is way too simplistic (i.e. wrong) as well. It'll be interesting to get some data on charge times under normal use conditions as this will key to determine if I add solar panels or not.

-Brian

BSMSbuddy said:

Hey Dean,

Thanks for the article; that all makes sense. I was definitely incorrect in my description and the charger is indeed connected to the battery and not the alternator. (I hadn't even heard of a BCDC controller before the seller described it to me.) Based on your article, my back-of-the-envelope calculation for charge time is way too simplistic (i.e. wrong) as well. It'll be interesting to get some data on charge times under normal use conditions as this will key to determine if I add solar panels or not.

-Brian

Click to expand...

Glad that was helpful. Which charger do you have and what size? My Victron is 30 amps and I see over 30 amps initially, then it tapers down to mid 20s depending on how run down the batteries are. Heat is a factor also. they put out a lot of heat when charging and will start to derate if too hot. For the Victrons it starts at 104F (40C) and derates 3% per degree Celsius above 40C.

Whether or not you need solar will depend on power needs and whether you are driving everyday. Fridge and furnace fan (if you have one) are the big draws. One for each season, lol. This ship has probably already sailed but, why didn't you go for a top loading fridge? Much more energy efficient.

Dean

veryactivelife said:

Glad that was helpful. Which charger do you have and what size? My Victron is 30 amps and I see over 30 amps initially, then it tapers down to mid 20s depending on how run down the batteries are. Heat is a factor also. they put out a lot of heat when charging and will start to derate if too hot. For the Victrons it starts at 104F (40C) and derates 3% per degree Celsius above 40C.

Whether or not you need solar will depend on power needs and whether you are driving everyday. Fridge and furnace fan (if you have one) are the big draws. One for each season, lol. This ship has probably already sailed but, why didn't you go for a top loading fridge? Much more energy efficient.

Dean

Click to expand...

The charger is a 25 amp RedArc BCDC1225D. Since the camper has been empty until recently, I haven't really been watching the draw or charging at all. Running a few LED light bars at night doesn't make a dent. Even when we've run the heater all night, the 100 Ah battery only discharges by about 4-5%. Once the camper is built out, I'll be paying more attention to this.

The fridge will definitely be the biggest draw in our camper. I went with the front load for a couple of reasons, all of which are aesthetic. Basically, I didn't like any of the top load designs for integrating into the camper. I'd either have to make a drawer for it or use the top as part of the counter. Personally, this seemed a bit clunky while cooking or loading/unloading but is just my two cents. I also really liked the idea of being able to grab a beer out of the fridge after skiing without crawling into the camper (the fridge door will open to the rear).

The energy consumption is indeed a bit worse, but we might be able to get away with it. Comparing the specs for our fridge (Isotherm Cruise 85) with a Dometic top-loader of similar size and cost shows that ours is about 15% less efficient. (As I'm sure you know, there are pretty big error bars on this as it depends on operating conditions, temperature settings, etc.) From the fridge specs, I can get 2-3 days out of our fridge on a single charge allowing for some headroom, and uncertainty for our actual use conditions. I'm going to try and improve this a bit with extra fans built into the enclosure, but we'll see by how much.

For our use, we're usually driving, and thus charging, every day. For climbing, the camping typically isn't at the trailhead you use to get to the crag. (This is one of the downsides of a van or truck camper for climbers as opposed to a trailer you can park, or a tent for that matter.) How much driving depends on where we are so I will need some data on this too. If the fridge draw becomes an issue then I have two options. The first is that Isotherm offers a nifty little add-on that claims to increase the efficiency by 50% (key word: claims). It does this by sensing when your coach battery is being charged by the truck and turns down the thermostat turning your fridge into a thermal battery. I really like this clever bit of engineering but at >$200 I'd really have to wonder why I wouldn't just put the money into solar panels as that would help with more than just the fridge and the camper is already "solar ready". Time will tell though if I need to do either.

Thanks for the questions,
Brian

As you say it's trial and error (hopefully not too many). We've ended up with 320W on the roof, Victron DCDC 30amp charger with 4AWG wire from the starter battery and two 90ah LiFePO4 batteries. We run a Dometic 80 liter front loading fridge plus a 40 liter top load running as a freezer most of the time. Furnace, lights and device charging. After a year we've never needed the second battery. The real game changer for us was the DCDC charging.

Cheers
Dean

I see from the photo of your rig that you have a short wind deflector on the roof of the truck. Does that improve your fuel efficiency?

That was on the truck when we bought it, but I believe the previous owner added it to try and reduce wind noise. I don't have a sense for what the MPG is without it, and there's still plenty of wind noise.

The truck is the 6.7 turbo diesel and weighs something like 5 tons alone. It's a bit overkill for the 4wheel, but dang it's nice. Currently, I'm getting 15 mpg on straight highway and close to 20 in the mountains. In the mountains, I'm able to coast more downhill and am mindful not to accelerate too hard uphill.

Fridge:

The fridge (Isotherm Cruise 85) went in tonight without much trouble. I also added two 2" DC fans behind the compressor to help with cooling. These will draw cooler air in from under the fridge where I've left a channel for air intake. These fans are on a temperature switch I picked up from Amazon for a few bucks. This is pictured next to the white vent with the *bright* blue temperature reading. The white vent cover is right next to the compressor to help with ventilation. (I decided to vent into the camper as opposed to cutting a hole to the outside, which I discussed in a previous post. Time will tell if this works well enough.)

To add the fridge, I had to expand the fuse box capacity. The one that came with this shell model only had room for 6 circuits, so I ordered a replacement that added 4 more. I stuck with the same brand (Bussman) as it made for a simple swap and still fit nicely where the smaller one was. I had to cut out a new access panel for the electrical since there's now a cabinet sitting on the old door. I'll make hinged door for this at some point.



Here's a look at the extra fans installed behind the fridge. The thermocouple for the temperature switch that controls these guys is hanging off the wall. The fans sit just below the compressor when the fridge is in place.

I had some time to finish the drawers for the cabinets. I used Blum undermount soft close drawer slides on a recommendation from a cabinetmaker friend. They're full extension 18" drawers and were relatively easy to install* (after watching some youtube videos). I chose to go with a flip down cabinet door for the below the sink, but I'm not sure I like this. It'll be easy to change later if I want to. I still need to add drawer faces which I'll laminate green and edge band black. I also still need to decide on a latch for these.



I was also able to start the counter tops. I used the same 3/4" baltic birch as the cabinets, which I covered with a WilsonArt high pressure laminate. (This is the same product that I used to cover the sides of the cabinets green.) I haven't written about costs yet, but all of the materials for the countertops was ~$200, and I have enough left over to make a table top and counter extension that I plan to add later.

I finished the counter tops tonight and am more pleased than I thought I'd be. After ordering the laminate, I thought that I should have listened to my wife and chose a much lighter color. Then I learned that I couldn't exchange it so the thifty side of me decided I liked the dark after all. I think it turned out just fine. The back splash is just a pine 1x4 laminated and edge banded with iron-on black melamine. I need to do a little bit of caulking still but other than that, it's ready to go.



I used a rubber t-molding for the edge band hoping that this will act as a bumper as we're moving in and out. I bought a 25' roll on Amazon for ~$20. It was a bit manked when it showed but cleaned up on the install. If I were to do this again, I would spend the extra money to buy this from a local woodworking store so that I can make sure it's not kinked and twisted.



That's about all I'll get done before we take this out for Thanksgiving weekend. This is a little more cozy now to go hide out in the woods as we stay away from all things human. Still to do before winter: drawer faces, install Lagun table, add flippable counter top extension, install electrical outlets and gauges. I'll probably wait until spring to put in the sink and water pump and to add the additional bench.

great work!

Really nice looking rehab. I like , good job.

Russ