|Emerson Drafting Table - CC 2.0 by Tri Lox on Flickr
I'm still trying to source a van, so still just at a design level, and welcome your feedback. I have a floor plan, but it doesn't include everything, so a few comments below will hopefully answer your questions.
The most critical design drivers that aren't common with other camping designs are to be easily driveable (minimize backing up), and to have air conditioning when not on shore power. I know that AC on battery is a very difficult requirement; however, based on my calculations, it's reasonable as long as you can plug in at least once a day (or use a generator) and are obsessive about insulation.
The lettering will be easier to read if you open the image in another window.
I did this drawing in Google Slides at full scale: 1" = 1" and printed it out at the local Fedex office. This has already given me some initial design adjustment ideas. This printout is 36" x 140" on each side and cost $62 to print out -- well worth it from my perspective. The small type size on the drawing is because Google Slides has a maximum type size of 96 points.
Solar: 990 watts of solar, completely covering the roof area. This forms an attic area that should reduce the AC load.
Alternator: 12V x 50 amps (600W) Battery to Battery charger
Shore power: 20 amp circuit with 15 amps typical expected overnight as needed. This is adequate to full-charge the batteries from empty in 6 hours at 1,500 watts.
Generator: Honda EU2200i for when shore power isn't available.
3x SimpliPhi 3.8kwh 24v -- 11,400 Wh nominal, 9,120 Wh useable @80% discharge
Midea U-Shaped, 8,000 BTU, inverter soft start, maximum draw 768 watts, 15 EER. Side vented and ventilated (and yes I know this is a major pain to build in)
Continuous 25 CFM, on timer 100 CFM, on temperature switch 200 CFM.
Propex HS2000 propane heater (the math just doesn't work on electric heat).
Blended insulation value equivalent to at least R-5. Probably will use one inch of Polyiso wherever it can go and lots of Great Stuff. Ventilated box with layer of interior hard-surface closures for sliding door, back door, and cab area. Extra effort to insulate against nuisance sounds (maybe Ensolite layer on large panels along with mass loading the sheet metal).
Three configurations at a daily choice option: two 28" x 78" bunks long way // 52" x 73" sideways // 73" x 78" long way (but this takes more time to set up). In the bunk and mega king setups your feet go under the kitchen counter on one side, and under the air conditioner on the other side. 15" clearance above the mattress level.
Approximately 20 inches tall x 14 inches deep. This holds 2 propane tanks, one small gas can, and a generator. The top of the garage becomes a shelf that serves as an end-table for the beds. When the back doors open up, and my insulation partition is folded back, there is an unobstructed view out the back.
30 inch dedicated counter with sink. 52 inch auxilary counter that gets put away at night. Expecting only electric appliances except for a propane grill to use outside.
16 gallons dedicated + 2 x 2.5 gallon jugs for 20 gallons total. The jugs are so the water can be refreshed from a situation where we just have water available, but no hose connection. Some campgrounds are like this. Grey water goes to a jug that is emptied manually (probably 3 gallons). No water heater in this design -- small amounts of water can be heated in the electric kettle for dish washing and sponge-bath bathing.
I will provide a water outlet out the back so one of those instant propane heaters could be used for an outdoor shower. However, I don't expect that to be a common scenario for us.
We think a dry toilet (wag bags) will be adequate for us. We do have the option of using a portable cassette toilet or some other variations. There will be a cabinet underneath the refrigerator to hold it.
That's about all I have worked out so far. There are an amazing number of little decisions to make as well. I'm hoping to buy a new Promaster in February with the factory swivel seats and 220amp alternator, there just aren't any available nearby right now. I look forward to your feedback and will post additional progress.