Overland Build

sipma02

Member
This is crazy interesting and will be amazing if you can pull it off. You should start a seperate thread and document it (so it doesn't get lost) I will be following along for sure.
 

Midwestdrifter

Engineer In Residence
I am working towards an order of 8x 280AH LFP cells. The recent advances in LFP tech have yielded some supremely high density cells. A 560AH pack with these cells is less than 1 cubic foot, and weighs ~100lbs. Due to the small size, exterior mounting becomes more reasonable. With 1/2" of insulation, the resulting box would only need ~46W of heat input with a delta T of 55F. Which seems pretty reasonable. Going to 3/4" insulation yields a ~30W heating load. While interior mounting is an option, I am always short on space. Currently I am considering exterior mounting in the spare tire area. I was considering cutting out a section of the floor, and making a flanged, doubled walled, drop in box.

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Midwestdrifter

Engineer In Residence
This is crazy interesting and will be amazing if you can pull it off. You should start a seperate thread and document it (so it doesn't get lost) I will be following along for sure.
Air conditioning and refrigeration may seem like voodoo at times. The hard work is already done for me though. Flow rates, line sizing, cap tube, etc. Being a purely mechanical unit helps. I am also kicking about the idea of a variable speed drive and an arduino for control, but that's a ways down the line. There are good resources for the DIY savvy. Your typical HVAC tech isn't doing the math to figure most of the hard stuff out, they consult tables and other resources for best practices, and then assemble it up.

There are a few crazy folks who have modified window AC units for off grid usage. Adding a water cooled condenser, remote evaporator for a fridge, etc.

I would probably dive into getting the AC setup, but I need to wait for the batteries before I install, as the condenser occupies the spacer where my lead bank is currently. I will start accumulating the parts I need at least.
 

RVBarry

Member
We have a TV/monitor mounted at the foot of the bed. It is on a swivel arm,
Hi, I'm really enjoying reading this thread...

2 questions:
1. How has the TV mount and TV held up to rough roads?
I'm guessing the 12V panels are a bit more rugged?

2. I saw your mention considering a permanent shower pan, have you decided how you would do that?
I've been thinking of the same thing, with wood inserts to fill the pan.

Sorry if you've covered these already, but I wanted to reply before I forget.

Thanks!
 

Midwestdrifter

Engineer In Residence
The arm and TV are still going strong. I have a elastic cord I strap over the TV when we are in motion which holds it in place.

The shower pan has been ordered. I am making it front 16 gauge stainless steel, about 1" deep with a lip flanged lip. Since my floor is raised by 0.5" with 1/2" plywood on top, I can cut out both layers and insert the pan into the floor. From there I can make a filler piece. There are some fiberglass shower pans made for RVs, but they are too big for my application.
 

RVBarry

Member
The arm and TV are still going strong. I have a elastic cord I strap over the TV when we are in motion which holds it in place.

The shower pan has been ordered. I am making it front 16 gauge stainless steel, about 1" deep with a lip flanged lip. Since my floor is raised by 0.5" with 1/2" plywood on top, I can cut out both layers and insert the pan into the floor. From there I can make a filler piece. There are some fiberglass shower pans made for RVs, but they are too big for my application.
Thanks!

New shower curtain with 4 roof attachment points, side entry and slot for temp adjustment. Also snaps for floor pan.
Since you're going to be using a steel pan, you could have magnets in the bottom of the curtain. Some curtains are sold with them, for steel bathtubs.
 

Midwestdrifter

Engineer In Residence
Since you're going to be using a steel pan, you could have magnets in the bottom of the curtain. Some curtains are sold with them, for steel bathtubs.
That is a good idea. I need to double check my order to see, as some 300 series stainless isn't magnetic. I could put magnets on the back side though. I will have to test some neodymium magnets to see if they are strong enough. I could also opt for magnetic snaps (I use them on my curtains). Easier than button snaps, but good shear pull-out strength.
 

Midwestdrifter

Engineer In Residence
Started tearing down the AC unit.















The evap and controls should fit over the bed with a little work. Looks like the best cut is along this line. That leaves the compressor and fan with the condenser.



The liquid line from the condenser is ~1/4" nominal, then it goes to about 20 inches of capillary tube. The tube has some thick foam , followed by thin vinyl tubing. I plan to keep the cap tube with the evap, so I need 8-12ft of liquid line. Gas side return measures to ~3/8".

I am not sure if 3/8" is sufficient for the gas return. My first thought is that is should be okay for just 10ft.

The other issue is the cap tubes metering control. Since the tube will not be inside the cooled enclosure, it may be too short. I think there is enough insulation, that I can remove it to compensate if necessary.

For the evap fan, I just ordered a used motor/fan from a similar model (28$ on ebay). Hopefully its a good fit. Since I am keeping the fan motor mount with the condenser, I will need to make something to support the evap fan. It appears that a flat mounting plate will work.
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My current plan is to cut the unit in half, draw up the necessary metal bits to enclose both units, and to restore the drain pan on the evap. That will include a back wall to support the fan motor. At that point I can install and charge. No charge volume listed on the unit, but a good shows it may be 6.35oz. I will need to adjust for the longer liquid line, which may be another oz or two.
 
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Midwestdrifter

Engineer In Residence
Anyone got experience with R290 (propane)? I am looking at the specs and it looks compatible with R32 systems. I need to check oil amounts and charge weights, but it doesn't require an EPA license, so I could charge myself. The only issue I see is the the compressor displacement needs to be 40% higher? In which case it wouldn't work.
 
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Midwestdrifter

Engineer In Residence
We have decided to go full-out on the van for the next 60 days or so. Galley, battery pack, shower, and some other storage upgrades are on the list. Its going to get busy. Then we should have the fall and winter to enjoy ourselves a bit before we start the job hunt again.
 
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Midwestdrifter

Engineer In Residence
Making progress on the galley design. I tried some of the SMAW/stick aluminum electrodes on some 0.1" aluminum I had lying around. The results were atrocious. Brutally hard to start at low amperage and very short arc length. The flux pool is indistinguishable from the metal pool. I can't get the arc to follow well either, as the flux forms a tube at low amps. They would probably work at high amperage on thick material, but not an option for me on this project. I gave in and ordered a spoolgun. If I am careful I should have enough C25 gas to finish the shower pan, then I can get an argon refill.

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I picked up some 1/8" PE plastic to make fender flares. They turned out okay. I just need to find where I put the screws for them...

 

Midwestdrifter

Engineer In Residence
I am thinking Southco M1 Latches. They have a model that works with 2-7mm thick front panels, which is ideal. I am not looking forward to welding all these bins up. But I am tired of water damage, splintered edges, and broken glue joints in wood.

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99sport

Member
You might consider a Spal fan for your AC - they have a catalog with hundreds of pages of automotive fans with cfm, pressure drop, and current draw. I saved a reduced version of the catalog with the smaller fans that I thought were a good size for a DIY minisplit (which I hope to do eventually, but van progress has slowed to a crawl). Relevant pages attached. ACCA manual D calcs work out to 325CFM for 5000 BTH/h (at least in my climate), so that is about what you would want for proper dehumidification. I know you already bought an R32unit, but R410A bottles are readily available (and relatively inexpensive) on ebay.

My plan is to put everything but the evaporator under the van (keep the hot compressor outside) and then 3D print a tub with a drain spout for the evaporator to go inside, on the floor in a cabinet - the spal fan will pull air through the evaoprator, but it will be next to and ducted from the lithium system to provide battery powered cooling for mild temps / short durations.

You mentioned moving - where are you off to? If you are interested in an aerospace job (or a pair of them) in Southern California send me a PM.
 

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So here is a thought on a self retaining bin without slides.

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Here is the bin at full extension. In order to remove the bin, the front is lifted up as it is pulled out, which allows the tabs to clear. If desired the front face can be attached to wood etc for a finished appearance.

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Am I the only one that can't see these? Also what are your plans for thicknesses of aluminum of the various components? Thanks Man!
 

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