And so the adventure begins.

[AKat777]

So I will cronicle the progress (or lack of) here so that others may provide helpful ideas along the way. I will attempt to edit much of what will be said along the way when things dont go quite as planned (hehe).

A little about what I am looking to accomplish. I posted this in a couple other threads, but will state it again here to keep all the info in once place for anyone following my foolhardy adventure
I currently work maintaining the fleet for a travelling show. As such, I need a decent sized space for all my tools. The show has been reasonably good to me, but the 8X10 space they provided for my living area just isnt big enough, I am being overrun by tools, and those are just the ones I bought here, not the entire storage unit of tools back home.... Even should I leave the show, I will end up using the truck for residential rehabs. Flipping houses is not as sexy or as easy as they make it out on TV, but you can make a decent living at it if you know how to build a home. Especially if you dont need a motel room for weeks at a time while doing the plumbing or wiring which would make it so you cant stay in the house..
So...I decided to do a DIY conversion. This website was a huge help right out of the gate. After reading multiple threads I decided the type of truck box I was looking for. I wanted the furniture moving box for the pre-built attic area which will become the bunk. The rest of the space (the 6' attic was overkill, but it came with the truck, so I will use it) will be lightweight storage for clothing or something else very light. I dont want to overload the attic with weight.
The box itself is 25'. I will be using the last 10' of the truck for a workshop/tool storage area. (it will be a nice change of pace to not have my tools (literally) under my feet) This leaves me with little under 15' for living space, which should be enough considering the bunk is over the cab and not included in the 15'. The back of the truck has a working 1800lb liftgate, which will make loading and unloading rollaways filled with tools *much* easier

First the before pics. The truck itself is about 300 miles away from me atm, so the pics are off the net, sorry for the quality, but you will get the idea of what I am working with at least

The very first question is the decals/vinyl on the outside.. heat gun and goo gone to remove them would be my first choice. Paint will be last but I have read much on the subject so far, and I am wondering why an oil based primer but a latex/acrylic finish?

Onwards to the inside (and the important stuff). I have not seen too many pics of the insulation as it's being installed. I am guessin everyone used either straight rigid board, or lined rigid board. Where did everyone draw the line? I am thinking atm I want a R14 (or thereabouts) so I need a double layer (for a total of 2 inches). But having never done this before, I am wondering will that create chaos when it comes time to install the windows?

More as I think up an intelligent way to present the 1,000,001 questions running around in my head atm.

 

[AKat777]

Insulation

The first question that comes to mind is the crush value of the rigid foam. If I have 2 inches below the subfloor, am I going to run into problems with the foam crushing and creating waves in the floor? I have used foam panels to insulate a slab foundation before, but once the concrete sets, it will not affect the structure if the foam moved. The walls and ceiling are obviously not a problem for this, but I am wondering if a 5/8" plywood will be enough to evenly distribute the weight to avoid any issues, or if 3/4" would be better.

Another thought pops into my brain, and that is the 2.5-3" height of the new floor will create a (minor) problem with the side door. I can always use some angle to close up the gap. In case anyone is wondering, atm I am not planning on removing the side door. It works just fine, and I see no reason to remove it. And I can see several reasons not to. The first being if I make it smaller, I will need to reskin the area where the old door was. Having limited experience with this, I am not positive about the outcome. And since it isnt broken, no need to fix it..lol I will be removing the exterior latch in favor of a 'normal' door handle (and one that can lock from the inside). I am not sure what I will find inside the door itself, it does not sound hollow. But that's a bridge for another day

 

[Bob86ZZ4]

Yay, another fun conversion project to watch. Thanks for starting this thread. Have you read the thread about the Stealth build by Randy St. Clair? That might be useful. I'll find the link.

 

[Bob86ZZ4]

Here it is: http://www.truckconversion.net/forums/f97/stealth-camper-build-thread-4102/

 

[Oscarvan-TC]

For the floor I would put runners under the 3/4" plywood. On the seams, as you will otherwise never keep them even and then, say, 2 feet OC. This should take care of any compression.

 

[Ran D. St. Clair]

Enjoy the Adventure

Since you are building from the existing box in, there are lots of similarities between your project and the Stealth Camper I built. Bob86ZZ4 gave you the link to the thread (Thanks Bob). I posted a ton of pictures in the photo gallery. Just look for keyword "Stealth".

I tested R-max foam for crushing and found I could not crush it with 5/8" plywood on top. I did use supports under the seams, but nowhere else. In my case I used 1/2" foam under the floor, 1 1/2" in the walls, and up to 5" to 6" in the ceiling, depending on the arch.

Personally I figure windows are a liability, but many can't imagine living without them.

I have to tell you, just this once. You can probably buy something close to what you want far cheaper than building it. (but building is more fun...) Others will tell you the same. I spent over $40K on my little 14' box truck. The good news is that you will get exactly what you want.

Oil based primer and latex top coat? Sounds like a bad idea to me. I was told you can put oil base over latex, but not the other way around. The latex will not adhere properly and will blister. Assuming you are talking about the outside, I am not sure that any type of house paint is the way to go. Then again, I am no paint expert.

Good luck!

 

[AKat777]

Since you are building from the existing box in, there are lots of similarities between your project and the Stealth Camper I built. Bob86ZZ4 gave you the link to the thread (Thanks Bob). I posted a ton of pictures in the photo gallery. Just look for keyword "Stealth".

I tested R-max foam for crushing and found I could not crush it with 5/8" plywood on top. I did use supports under the seams, but nowhere else. In my case I used 1/2" foam under the floor, 1 1/2" in the walls, and up to 5" to 6" in the ceiling, depending on the arch.

Personally I figure windows are a liability, but many can't imagine living without them.

I have to tell you, just this once. You can probably buy something close to what you want far cheaper than building it. (but building is more fun...) Others will tell you the same. I spent over $40K on my little 14' box truck. The good news is that you will get exactly what you want.

Oil based primer and latex top coat? Sounds like a bad idea to me. I was told you can put oil base over latex, but not the other way around. The latex will not adhere properly and will blister. Assuming you are talking about the outside, I am not sure that any type of house paint is the way to go. Then again, I am no paint expert.

Good luck!

I read the stealth article (good read) but I found the picture gallery to be far more enlightening. As a starting example, I loved the before pics of the stud walls exposed and the wiring conduits running in the walls. If I stud the walls (even with 2X3's) I can go insane with the insulation. (The outside skin is attached to the metal runners, and there is 1 layer of insulation, plus another 3" to go. Talk about R value and soundproofing...lol. I am suprised you put only half an inch on the floor tho. 5 in the roof sounds good, since we all know heat rises and most of your heat loss is in the roof.

Has anyone tried using closed cell spray foam? After you stud the walls in and get the electrical set up, it would completely seal the walls/ceiling. It would also strengthen the walls. Not sure if that's a good thing tho, considering the box may 'twist' on the frame? Has anyone had problems with the walls shifting because of this?

BTW, your van looked *awesome* far better than my project will come out..but how did you manage to spend 40k? I am looking at 500 for a top of the line toilet (the simple things in life sometimes are the most important..lol), 500 for a shower (btw, anyone use a regular shower enclosure instead of a 'rv' model?) 1k for a fridge, 500 midgrade stove. So 2k for appliances (assuming I dont cheap out and use the apartment 4' fridge I have in storage, heh) probably 1500 in insulation, the tanks are a big ? at the moment, and a discussion topic I will post after dinner. (size, location, etc etc). But average 500 a pop is still only another 1500. 1k in lumber, and I am still at 7k. even if my insulation is really low, double it to 3k, and still only at 8k. (btw, I already own a 6500 gen and a 1500 portable, those wont be added into the price). And I dont know how much the electrical system will be. Currently I am planning on running two 50 amp shore cords. One for the 'house' and another for the workshop, since most of my corded tools are 10-15amps each. And the space heater I use to heat the house is a true 15 amp draw, it will have it's own circuit. (Comfort Furnace..worth every penny of the 350 I spent for it) No idea yet what it will cost to repaint the outside. I know what color it will be tho. The dark blue stripe from the Atlas logo is the color I am going with.

 

[AKat777]

Tanks

And onwards to another topic. The tanks. Everyone who has been in the RV community for more than a day knows you have 3 tanks. But what size tanks are considered 'adaquate'. As a single person in a 15' living space, one might suggest a 25 or 30 gallon tank as being enough for the blackwater and greywater tanks. In my current situation the greywater is a non-issue, since the show pipes the greywater out directly.

As I price out the tanks, I quickly realize that the price of the tank does go up, but not proportionally to the size. ie, a 25 gallon tank might cost 218, while a 50 gallon tank only costs 300. Using a hypothetical 2 flushes per day (we have facilities on site, so it will not be utilized 100%) at a gallon each, a 25 gallon tank needs to be emptied every couple weeks, where the 50 gallon tank only needs once per month (approx). Since I pay the show the same amount regardless of size, and I have the room, it makes sense to use a larger tank, unless someone can show me a reason not too? (and I do realize some toilets out there use a great deal less than a gallon per flush, but it's a reasonable number to start the discussion with.)

 

[Bob86ZZ4]

My coach has a 25 gallon black tank and 75 gallon gray tank. My wife and I can go about 5 days before they're full. Now that's with taking showers every day. And not being all conservative about flushing. The rv toilet doesn't use anywhere near a gallon a flush. And we almost never use public facilities. So, if you're out and about during the day and can use the other spots you're going to greatly extend your range. Also, it's not a big deal at all to flush them out. I think it's actually better to flush them out more often than not. Less time for stuff to start growing in there. When I bought mine I thought it seemed odd to have a 75/25 ratio. But, they both seem to fill about the same rate. Another thing, forget about level monitors for them. At least not the in tank kind. I've heard those ones that only mount to the outside work okay. Mine has probes screwed through the side of the tanks. They've never worked as far as I can tell. My previous rv had the same type and those didn't work either. I just make a habit of shining a flashlight down the hole once in awhile to see how high it's getting. And if my gray tank gets full it backs up into the shower so I know it. And my fresh water tanks are under the bed so I cut a hole on the side panelling and put a cabinet door on it. Then I just lift up the door and shine a flashlight in to see how much fresh water there is. I much prefer this method over some electronic means.

I've heard from the guys that have built their own, take your best estimate of cost, double that, then add some more, and you might now be pretty close to what it's going to cost. And you'll never ever ever be able to sell it for anywhere near what it cost you. But, most everybody that's built their own is glad they did and are enjoying their rigs. I didn't have to make the decision of buying/building. I have absolutely no skills to build one.

 

[AKat777]

After the effort going into this rig, I wouldnt even *think* about selling it. Also, the rig wont be as sexy as the Stealth Project. I work with diesel engines and fleet related activities all day. So I am covered in grease, oil, and fuel on a daily basis. So I am not going to spend 20k on the interior only to ruin it a year later. I am thinking painted plywood for the walls, so they can be sanded and repainted when they get crappy. I could just go with vinyl, but I havent seen anything I would be happy with.

Speaking of the tanks, you mention looking down with a flashlight. obviously when you 'flush' you open the valve to the tank below, but I didnt realize it was that open you could peer down to check the level. I had heard the monitors were a 50/50 shot on working properly, but I was also afraid of standing in water while I was taking a shower, lol. I realize flushing out the tanks isnt a big deal, but I am looking at the long term costs while I am with the show. It's cheap to pump out (15 bucks) but why do it every two weeks when a larger tank lets you do it once a month? And things growing in your black tank is a *good* thing. Help to break down the solids

 

[Ran D. St. Clair]

That's got to be the first time anyone ever called the Stealth Camper "sexy". Compared to some of the beautiful work I have seen on this site it is downwright plane.

There is a detailed listing of what I paid on page 26 of the Stealth Camper Build Thread. I may have some things you won't have in there, but yours is a bigger box with many things I don't have.

blizzardND is another builder of his own rig that will confirm that the cost is 3X what you plan and still climbing. He also has a much more detailed list of expences than what I have that you can get in spreadsheet form if you ask.

Spray in foam is a great idea. Some have done it with very good results. I believe geofkaye is the expert on this site for doing it. It might even be cheaper or faster than the sheet foam I used. I spent many happy hours (days, weeks) slicing sheet foam and stuffing it into place. It got tedious after a while.

As for box twist or flex. I have had no difficulty of any kind. The seams on my inner plywood pannels haven't shifted at all. My box is FRP (Fiberglass Reinforced Plywood) which is very sturdy though. Your box is probably more flexible.

I can't speak to tanks as I don't have any. Well, 10 gallons of fresh water, but no black and essentially no grey. geofkey is a big fan of the incinerating toilet "Incinolet" and you seem to have access to plenty of electrical power to make it work. Some people really like their composting toilets (I wish I had gone that way.) Black tanks aren't really necessary, but of course the majority of standard RV's have them, so most people assume that they are. Grey tanks are necessary when you can't dump on the ground, which is considered not cool in most places. If you are going to have a shower (I don't) then you will need to catch the water somewhere. Don't forget, water is heavy, and tends to slosh. You might not travel with full tanks, but somtimes you have to, at least a little ways.

The weight of the buildout adds up, not to mention all of your tools. I was surprised at how much heavier my little 14" box truck got. You need to be careful about how much weight you add and where you add it. Overloading the front wheels is a common problem. Some builders weigh everything and do detailed calculations. Others build their truck and then find they have to shift stuff around, or not fully utilize their forward storage, or both. Go find a truck scale with zones for the different axels, and then drive the two right wheels (or left) only onto the scales. That will give you a base line to work with. I show those calculations for my finished truck on page 24.

Good luck!

 

[AKat777]

Compared to my down and dirty industrial look, your little van is sexy, dont sell yourself short. You did an awesome job with the space you had available. I loved the cabinets over the toilet, those are nifty. But with no stealth plans on my end, I open up many more possibilities...gen outside, running large amounts of shore power, lawn chair on my liftgate (ok kidding about the last one). The only thing going into my rig that you dont have is a dinette which I can make out of a 100 bucks worth of lumber, and a kitchen countertop which I can buy for 89.00 at any local Homeless Depot or LowEmployees.

Comparing your project buy list with mine, I see you included the price of the van. So you actually spent 25k on the conversion itself, which I can see. Initially I thought you spent 40k on the conversion. And I figured you had to have gold plated faucets and a spiffy toilet that gave you a happy ending with every flush On a more serious note tho, there is no way you could convince me to spend 4700.00 on a toilet. Other items I already own. (fridge, generators,matresses,TV,laptop) so I dont spend that money. But to be fair, when pricing out the rig for insurance, I need to add that money back in, since I did spend it, just not with the conversion in mind.

Items I am not sure would include electrical. Not because I have never run wire before (I rehabbed 2 houses and built 2 from scratch solo) but because I am not 100% sure how to handle the main power panel. I will have 50 amp shore power coming in, but will I run all a/c in the interior, or dc for lights / possibly fridge.. a dc fridge is horribly expensive, I have a couple ac fridges in storage atm. And I have a hunch after I finish this truck, it will be like many other home projects, I will look at it and say do this different, do that different, and start on another truck..And will spend more and improve on the design the 2nd time around

Unlike many reading these rambling thoughts of mine, I have a fairly captive and willing audience for selling this project should I choose to. The travelling show will always have people looking to upgrade their living quarters

 

[Ran D. St. Clair]

As far as electrical, can you give us more of a hint. Does this thing need to boondock, meaning run on batteries? If so you need batteries, a battery charger/inverter, and probably a transfer switch. If it's more of a plug it in design then the electrical is more of an elaborate extension cord, or cords, probably with some circuit breakers. You might still need a transfer switch, or you might keep things simple and manual, like plug it into shore power or plug it into a generator.

Lots of people in the RV world would recommend a power management system that checks for miswired inputs, high voltage, low voltage, etc. Some will also recommend an auto-transformer that boosts low voltage to avoid blowing things up with motors and compressors like refrigerators or air conditioners. You probably know how good or bad your power sources can be.

Speaking of such. Will you have an air conditioner or possibly 2?

Modern high efficiency residential AC powered refrigerators are suitable for RV use. For short trips you can just keep them closed while you travel. For longer trips you would need batteries and an inverter.

You can run some things off of the 12V truck starter batteries, but that's problematic. Starter batteries are not deep cycle batteries so if you draw them down much powering an inverter you will soon be replacing batteries. That and you can easily find youself unable to start the truck. Depending on just the alternator to charge the starter batteries when they are also the house batteries is probably not going to work unless you drive a lot and pull current from the batteries very little.

The possabilities are many, so give us more information about your off grid needs.

 

[AKat777]

As far as electrical, can you give us more of a hint. Does this thing need to boondock, meaning run on batteries? If so you need batteries, a battery charger/inverter, and probably a transfer switch. If it's more of a plug it in design then the electrical is more of an elaborate extension cord, or cords, probably with some circuit breakers. You might still need a transfer switch, or you might keep things simple and manual, like plug it into shore power or plug it into a generator.

Lots of people in the RV world would recommend a power management system that checks for miswired inputs, high voltage, low voltage, etc. Some will also recommend an auto-transformer that boosts low voltage to avoid blowing things up with motors and compressors like refrigerators or air conditioners. You probably know how good or bad your power sources can be.

Speaking of such. Will you have an air conditioner or possibly 2?

Modern high efficiency residential AC powered refrigerators are suitable for RV use. For short trips you can just keep them closed while you travel. For longer trips you would need batteries and an inverter.

You can run some things off of the 12V truck starter batteries, but that's problematic. Starter batteries are not deep cycle batteries so if you draw them down much powering an inverter you will soon be replacing batteries. That and you can easily find youself unable to start the truck. Depending on just the alternator to charge the starter batteries when they are also the house batteries is probably not going to work unless you drive a lot and pull current from the batteries very little.

The possabilities are many, so give us more information about your off grid needs.

Part of why I am unsure of what components I will need is because I am still deciding what I want to do. While at the show, I have basically unlimited shore power. And I know about the quality of the electricity.. I maintain the generators (total of 3) that supplies the RV's and the show itself..hehe. Away from the show is when things start to get really murky. I could get a set of 4 (6?) deep cycle marine batteries and some sort of a switch at the breaker box to choose input. But that would require an inverter, a switch (forget what it's called at the moment) in between the truck batteries and the 'house' batteries to allow the house batteries to help with starting the truck, and charging the house batteries while the truck is running. The switch prevents the truck batteries from being drained, so even if you kill the house batteries you can still start the truck, and recharge the house batteries. (there is always the car charger I have in storage as well, lol).

At the moment I am leaning towards a house on wheels that relies on shore power. I dont plan on doing a great deal of travelling with it. On the other hand, halfway through the project I might decide to toss 4 panels on the roof, and a battery rack under the truck for free power. I can certainly survive on less in the house, but the workshop in the back just isnt practical to try to run on batteries. Most of my work tools run on a *minimum* of 7.5 amps out to 12-15amps for the good stuff.

I think I am going to put an AC unit in, but a small one. 15' of living space that will be super-insulated (I think I will be trying spray foam. Worst that happens it does not work and I scoop it out to put in rigid foam) wont take much to cool off.

The workshop and the house will be running off separate shore cords. As I said previously, the workshop is an electricity sinkhole.

As you can tell from my random rambling thoughts, this truck is being built with a fairly narrow specific use in mind. I should consider other things as I move forward, but I know what I intend to use it for. It will be parked in the show, or it will be parked next to whatever residential rehab problem (oops I meant rehab project..lol) I am working on at the time. So I am thinking shore power 95% of the time, 5% travel time, which I can plan for, ie empty the fridge. Or a small pack of batteries and an inverter to run the fridge from place to place. Which would require almost no additional work.

 

[Ran D. St. Clair]

I am assuming you want the lowest cost solution. You can go with no house batteries at all. That implies the fridge and other AC loads are off when traveling. The next step up is two Sam's Club 6V Golf Cart type batteries. You will need to learn to maintain them properly, keep them watered and charged, check specific gravity, etc.

Then you have to size your inverter to match the load. Minimal solution would be to just support the fridge and some minimal loads like a laptop charger. You can probably get by with a modified sine wave inverter which will save some money as well. I can't guarantee it will work for everything though, that is why I spent the money for a pure sine wave inverter.

You can forget about running your Air Conditioner (AC) off of the inverter, or a microwave, or a toaster, or even a coffee maker, unless you get a big inverter, and then you can forget about running the AC off the inverter unless you have substantially more batteries. Running any of those things implies firing up the genny or plugging into shore power.

For a small AC the Coleman polar cub is one of the lowest current draw units. Insulation is great, but it still takes quite a while to cool down the thermal mass inside the insulation. You can probably expect the AC to run on the compressor 50% of the time if you are in 105 degree heat, and that is only after it stabalizes at the desired set point. Unless they are double glazed, windows are terrible for letting heat in/out, even double glazed not so great.

There is no substitute for doing the math to figure out what you really need.

There are lots of ways to connect between the starter battery and the house batteries, including no connection at all, which isn't a bad idea. Some use a latching relay that only connects when the truck is running. Some use a pair of diodes so one battery can't draw down the other. Some use a fancy (and expensive) solid state device that is smart about making the connection. I used a simple and cheap 200A battery disconnect switch from the auto parts store. I use it rarely.

If you get into solar pannels and all that then you are way beyond a minimal solution. I can't see how it works for your situation anyway, but it's your call. There are some regulars on the Escapees forum who are much more qualified (than me) to give advice if you decide to go that way.

If you have batteries you need a battery charger. I would suggest one that is integrated with the inverter. You probably also get a transfer switch in the bargain. One advantage of buying the package instead of piece meal is you know that it will all work together. Ideally you want a 3 or 4 stage charger that will pump up the batteries quickly so you don't have to run the genny for a long time. If you are on shore power this doesn't matter so much.

Many would recommend a battery monitoring system that measures the current in and out, and works like a gas guage. For a minimal system you can live without it if you are prepared to monitor battery voltage and be aware of all the other clues that your systems will give you. One advantage of cheap and minimal batteries is that your learning mistakes won't cost you so much.

You really want a proper roof vent fan, like Fantastic Fan or similar. Lots of times you need fresh air as much as anything, and it is much less of an energy hog than AC.

Good Luck!

 

[AKat777]

I was fairly certain the large appliances were out of the question when it came to running off batteries. I was also thinking for a bare minimum set up to use 2 deep cycle batteries (located in the workshop to avoid any fumes from the battery box) with an inverter on the wall separating the house from the workshop. I was thinking mostly the fridge, and perhaps the roof vents to keep air moving. (air moving obviously not an issue when the truck is moving..lol), I know they are needed, but I am still cringing at the thought of punching holes into my roof. I never had a house roof leak on me, but this is slightly different, and there is always that possibility.
Atm, I am thinking 2 holes, one for the AC and one for a fan. I can always work out something after the fact if I need it. (more batteries, bigger inverter, etc). But this is going to be a very very basic box on wheels with a place to put my head to sleep, and a place to take care of those byproducts of eating well

 

[Ran D. St. Clair]

Ceiling vent fans are typically 12V, not 110VAC. I used the MaxAir and like it. The snorkel type cover allows the fan to be used even in the rain. You can still have your little crank up lid inside the snorkel cover to seal things up tight when you want to retain heat/cold. The fan itself is high efficiency and moves the air well. Those little 6" noise maker fans you often see inside the crank up lids are a joke. The snorkel and crank up lid can both be had in transluscent white, so you get a modest sky light in the bargain. You can block the light, and insulate by stuffing a pillow in the hole when you want.

I would suggest that your 12V system be limited to the house, not the shop, except for a single ceiling light so you don't kill yourself walking through the shop on a dark night. Other typical 12V items in the house area are ceiling lights, task lights (florescent or better yet LED) ceiling fan, and possibly a 12V matress pad as a low energy way of staying warm.

If you will almost always have AC power available then all you need is a couple of small 12V ceiling lights just so you can see to get in and out. You can even do that with AC lights, but that implies running the inverter all the time (which you may well do anyway because of the fridge). The only other downside is the coversion losses from AC to DC to AC, but those are pretty minor if the loads are small. It's just a matter of doing the math to see how long your batteries will last. Never plan on using more than 50% of their capacity though, otherwise you will kill them quickly.

 

[AKat777]

Soooo I did some shopping online for that all in one unit inverter/charger/transfer switch, and I almost fell off my couch.
800.00 for a 3000 watt pure way sine.. ouchies. And that does not include the battery pack to power the house..If I spend that kinda money, yes the inside lights will be AC. Might as well get my money's worth from the inverter

I just did the math on my insulation for spray foam, came out to around 2k. Not sure how much it would be to do it with 1" rigid, will calcuate that after work. THere is no doubt which is better insulation, but I am wondering the cost difference.

 

[Bob86ZZ4]

I'm wondering if a 3000 watt inverter will even run a fridge? Do you need a pure sine wave? I know they are the best but a modified is a lot cheaper. I'd say forget about the inverter. Just use the generator to run the fridge every once in awhile when you aren't hooked up to shore power. Or, buy a propane rv fridge. More money up front than a residential but they are soo efficient. Very very little propane use. And only a minor small amount of 12v needed for the ignition and the light when the door is open. And if you get a two way power one it'll run off shore/gen power when you want to to save even more propane. I know, you've already got a 120v household fridge you want to use. But maybe think more about an rv one?

Also, the toilet. Those incinolet ones are cool. Whatever one you go with you can't forget to test it in the driveway like Ran D did.

 

[Ran D. St. Clair]

3000W is not only big enough to run the fridge, it is big enough to run the air conditioner with room to spare. 3000W is 25A at 120VAC. A Coleman polar cub draws about 11A to 13A depending on how hot it is. Such a big inverter is expensive, which is why you don't want one like that. You probably need something closer to 3A for a refrigerator. That's only 360W. Don't take my word for it though, check the specifications, or better yet measure it yourself. Make sure you measure it in all modes of operation, including when the compressor first comes on. Most inverters are rated to handle more than the nominal current for a short time. Yes, a modified sine wave will probably run a refrigerator. Many have done it and perhaps some of them will chime in. I just can't make any guarantees. Motors run hotter and less efficiently if not fed with a sine wave.

Yes propane fridges are fine, and many use them. Thus far you have avoided the need for propane and all that entails. All electric (no propane) is getting more and more popular though.

All these systems and design decisions interact. More AC requirements, bigger inverter, bigger batteries, more cost. At some point you need to nail down the line between what you need and what you want. Once you define your mission parameters the rest of the tradeoffs can be calculated. Then you convert mission parameters to a design, which converts to cost, and forces you to rethink your mission.

I'ts entirely your decision of course, but I might start with batteries and inverter that only support your refrigerator and a few minimal lights for 24 hours maximum, and that's only drawing down the battery 50%. That should get you from point A to point B where you can plug in and charge up, or at least run the generator for a while. Once you have a rough idea of the cost you can go from there.