Theorycrafting Help

So after some more research, I am coming to the conclusion that a used Carrier or Thermoking APU (roughly $3-4k) is the best solution to my generator problem, and the cooling units that go with them don't suck. In fact, they're good enough I might want to use it as my primary AC (fewer holes in my insulated box, the better). Makes sense that they'd be good units, both have been making mobile refrigeration systems forever. Not sure I would trust their inverters over the Schneider, but they'd be decent as a backup.

They don't charge directly to 24v, but I can live with that (whole point of the Schneider is that it can charge from shore/generator power and invert). I'd have to get a welding shop to work up a mount, but I was going to need one to build the battery boxes and reinforce the deck under the generator anyway.

Still not sure about building my own refrigerator. I can see how it could be much more efficient, especially with being able to dump the heat outside and make the wall considerably thicker than any standard fridge. But getting the sealing right, especially for the doors, seems like it could be a real PITA.

Yeah, it's looking more an more tempting, the cost is not minor (roughly $1250-1500 for each, refrigerator and freezer), but the efficiency gains aren't, either (especially with the advanced controls that take advantage of a DC compressor's capabilities for variable RPM). I'm thinking that with lots of insulation, I can build a 16/12 cubic foot refrigerator/freezer setup that will draw considerably less power (by about a factor of 4) than anything remotely equivalent in a residential or commercial system. And I can build the whole thing to match my personal ergonomics (no bending over, or losing stuff in the back corners of the fridge). All of it running off the 24v, so that the inverter and generator aren't in the failure chain.

The only drawbacks are that it won't be frost-free (which means having to waterproof everything and allow for drainage) and it won't freeze/cool large amounts of stuff in a hurry.

I'm getting seriously tempted by that 30 SEER Mitsubishi split A/C, as well. Even with the losses for conversion (first to 115v AC and then stepping up to 230v) and parasitic loads, air conditioning on as little as 100 watts (probably closer to 150 with parasitic loads and conversion losses) is huge. With the sheer amount of insulation I'm planning, it's possible that I could really take full advantage of the 100w/2800btu mode of that model.

Did realize I had a significant flaw in my plan: If I use SIP for the ceiling, I don't think I can count on it staying structurally sound over the long term (essentially, all that would be holding up the ceiling is the bond between the particle board and the foam, and this application would shake it around a *lot*). Probably have to rafter the ceiling with something like aluminum lighting truss. This model appears to be closest to what I need.

Figured out a solution for the overhead strength issue: Raycore panels (not technically SIP's, but very similar) have wooden boards integrated into them. They aren't normally used this way, but what is? Anyway, they should be much better for my needs, the boards slightly compromise the insulation quality but made the whole panel much more reliably rigid. Roughed out a layout sketch for the whole thing, but it isn't on my tablet. I can post it later if anyone cares to see it.

That is interesting, I see that you used 6" Iso foam, how is it doing (with the minisplit) at climate control? Do you run the heat pump all the time? Do you have any backup heat source (if it got below the range for the heat pump)?

What about water, do you have any source/storage besides the rain barrel? What do you do with the sewage? Is that a macerating toilet?

My design target was, as I said above, a self-contained geek pod. It tends to be a given that I have to move every year or two for work, and I've really gotten tired of the hassles. Not just the packing and unpacking (although that certainly sucks), but all the trivial crap like getting utilities started, then getting them shut down, turning in TV equipment, phone service, closing out a lease and getting a new one, and on and on and on. When I was paring my stuff down to what could fit into the Rialta, I realized that I had tons and tons, literally, of crap that had gotten thrown in boxes 3, 4, 5, even 10 moves ago, and carted across the country sight unseen, over and over, for years. That I literally hadn't thought about in that entire time.

In living in that little space for a year, I realized that most of the things that go along with a permanent address are simply not necessary. For the last 20 years, I didn't bother getting to know my neighbors, because I wouldn't be around long. For furniture, I only needed a comfortable bed, a comfortable chair, and a decent place to work at my computer. I did miss having a shower I could actually use (the Rialta shower is 18 x 30 inches, you have to reconfigure the RV interior to use it, and of course there is not a lot of water in the tank) and the ability to fix my own dinners, store leftovers, and eat ice cream that I didn't buy in the last five minutes. And although most of that crap I carted across the country several times was completely disposable, I did still have several large totes worth of stuff with emotional value I wanted to hang onto (and leaving it at the mercy of friends or relatives long term would be begging future problems).

So that was my target: Everything I needed to be comfortable, no more and no less. All the basics of shelter and sustenance requiring no more thought or management that they would in a more normal living arrangement. No provisions for guests, or entertaining anyone but myself. Transportation for errands and such by scooter. No commuting to speak of, I'd park near work (if not literally *at* work).

And as much as possible, completely stealth. I spent most of that year in the San Diego area, and specifically near La Jolla, literally the worst place to be an urban boondocker when it comes to law enforcement. It is literally illegal to sleep anywhere in the San Diego area outside of a permanent dwelling or designated campground, and the police routinely roust anyone near the ocean in an RV, or anywhere in the county if they get calls from citizens. I eventually learned tricks for avoiding all of that, but the biggest factor was when I repainted the Rialta completely white, with black running boards and bumpers, and hung a ladder on the side. Making it look like a service/commercial vehicle cut my issues with law enforcement and nosy/paranoid homeowners to zero (it helped that the Rialta doesn't *look* like an RV, with that paint job it looked like some kind of weird cargo van).

So from the outside, I want it to look like just another generic truck. No windows, no RV-style doors, no obvious giveaways like rooftop vents and AC units. Just one more forgettable, ignorable truck, that I can park in any commercial or industrial area in the country and people literally edit it out of their visual field. Since I don't want to just survive, but live and be comfortable with all of my electronic gadgets, I've been putting a lot of thought and research into the generation and use of electricity.

And not that anyone actually asked, but here's the current layout plan, assuming a 8 x 26 foot box (if I could get one with a 8.5 foot wide box, I'd probably make the shower bigger).

Well, because you put me onto researching hot water as a heating method, I found out that this was a thing: 17k BTU diesel fired hot water heating for boats. More expensive and less efficient than the Airtronic, but...effectively unlimited hot water (it can be set up to maintain hot water tanks as well as multi-zone heating), 17K BTU is equivalent to 5000 Watts of resistance heating, meaning effectively instant hot water on demand, and the elimination of a major electrical drain.

It's tempting, even if it would cost about $2500 (compared to $1K for the Airtronic).