Saturday, March 15, 2014

Basement and Utilities

A motorhome with a basement? Sure, a basement is where you store stuff you use infrequently, and it's a term in common use by RV'ers. Often it's applied to storage that's accessed from outside the RV, but it can be found under seats and beds, too. The basement is also where you find a home's utilities: furnace, water heater, electrical panel, etc. Let's conclude our tour of the "rooms" in my motorhome design by taking a trip to the basement and the things it holds.

From the very beginning of the process of choosing a RV for my retirement, and deciding to spend long periods of time on the road, the most haunting question was: will I have enough space for all the things I need and at least some of the things I want. It's the basement in my Sportsmobile design that gives me confidence that the answers are yes and yes. I could have chosen other RV designs, larger RV designs, that wouldn't have made it a close call, but I wanted the opportunity to decide what is important to me and what I can live without. 

The Sprinter van doesn't have any exterior storage, so my basement is all inside the living space. The bulk of my storage space is under the platform bed:


The dimensions of the space are 72" by 45" by 23" which comes out to 43 cu. ft. As you can see, there's some space that's already occupied by the wheelwell, the water tank, and a few other things I'll discuss below. But even if the net usable volume is only 35 cu. ft., that's more basement space than some larger RVs with exterior storage. 

At the upper right of the space I've specified 110VAC and 12VDC outlets. Both of these will be handy if there's power equipment I want to operate outside the van. The 110VAC outlet will also be good for recharging any sort of battery operated tool I store in the basement. I'll keep an automotive accessory light plugged into the 12VDC outlet to light the space when needed. The skirt for the bed (beige color in the image above) is fabric attached with velcro. I originally opted for this design to save weight, but it also provides me with easy access to the contents from any direction.

So, what get's stored in the basement? There'll be a couple folding camp chairs, a toolbox, and a bundle of wood (kept in a duffle bag) for campfires. There'll also be a suitcase, usually filled with off-season clothes, but also available for trips I'll take overseas. The Cadac grill I described in the Galley post will also go back here. It has its own carrying case:

       

I'm also going to have a tent, at least one sleeping bag, and an air mattress. There may be times when I want the connection with nature that only tent camping can give. It will also serve as overflow accommodations for houseguests, whether it's for some kids we've brought along or just to relieve the "packed like sardines" sleeping arrangements inside the RV.

There's a couple other items that I'm considering taking along. One is a ladder; it just seems like a good idea to have a way to get up on the roof of the RV if I have to. It's surprising how compact a telescoping ladder like this one can be:


The other thing is... a sewing machine. I had never considered it, but one of my favorite RV blogs, by Andy Baird, made a compelling case for it. Just something small and simple, like this:


Will I use it to repair clothes? Yes, occasionally. Will I use it to make clothes? No, definitely not. But there's plenty of other things, decorative and practical, from window curtains, to custom bedsheets, to an exterior sunshade, that I can imagine trying my hand at. I think fabrics - canvas, plastic sheet, window screen, rip stop nylon - are underrated as a medium for invention.

I've estimated the volume occupied by all the items listed above, and they don't come close to filling the space available. That's a good thing. There's bound to be some things I've overlooked. There may be bulk food or supply items that I occasionally buy. For long trips into the wilds, I may want to take along extra jugs of water. I also look forward to finding irresistible items to buy on my travels, not to keep for myself - there won't be room - but to carry as gifts to my friends and loved ones they best seem to fit.

As I mentioned, the big blue box in the basement area is where fresh water is stored in the van. The tank holds 20 gallons, and is for drinking, dishwashing, and showers. This is the largest tank Sportsmobile offers without doing something completely custom, and it should be plenty for me. Recommended drinking water is in the neighborhood of 1 gallon per person per day. If I'm wilderness camping, I doubt that I'll shower more than once every other day, and those will be "navy showers", where you wet your skin, turn the water off, soap up, then turn the water on again to rinse off. With a low flow showerhead, I think two gallons is generous for such a shower, which averages to another gallon per day. So 20 gallons should last me 10 days completely removed from civilization. In the event that I do extended wilderness camping with some houseguests, it'll be time to lay in extra jugs of water.

There is some additional water-related equipment behind the tank; here's a view with the bed removed:


The smaller vertical cylinder is the water pump, the larger cylinder is an expansion tank. The water pump, of course, is to get water from the 20 gallon tank to the faucets at the galley sink and the shower. It's pressure sensitive, so it runs only when the pressure in its output line is low; that is, a faucet has been opened. There is a switch, though, to turn off its power when you know you won't be using water for a while. The expansion tank is an optional item that's on the high pressure side of the pump. The pump fills it with water under pressure, and then if you turn on a faucet, the expansion tank empties before the pump turns back on. This way, the pump isn't constantly cycling on and off. I'm specifying a 3 gallon expansion tank, so potentially, I could take an entire shower without the pump turning on. It also adds 3 more gallons to the total water capacity of the van. This one tank serves both the cold water faucets and the hot water heater. When the van is connected by a hose to city water, I'll be able to reach in past the fabric skirt, turn a valve, and conveniently refill the 20 gallon tank.

The water heater for the RV is in what you might call the basement annex: the space under the front couch. It's represented by the yellow cylinder here:


It holds six gallons of hot water (which incidentally, brings the total fresh water capacity to 29 gallons). Even when the van is hooked up to city water and I can afford the luxury of a long, continuous shower, that should be plenty. To make up for the small size of the water heater, RVs keep the water temperature set higher than in homes. I plan to have a temperature limiting valve installed in the water sent to the shower, so I can just turn the knob all the way up, have a comfortable shower, and not worry about scalding myself. The galley sink will have access to full temperature hot water for a good sterilizing rinse. I had thought about asking for an on-demand hot water heater - one that doesn't store hot water, but heats it immediately when you turn on the tap. However, as far as I've seen, those run only off of propane gas. Instead, I'll get a storage tank water heater that can run on either propane or electricity, so that when I'm plugged into campground power, I won't be using up my propane.

Having seen where the water comes from, the natural question is where does it go to? There are two 10 gallon holding tanks under the van, one below the galley sink and one below the shower, to store waste water. This is called gray water storage, since sink and shower water isn't particularly nasty. I will have to open a valve under the van to empty each of these tanks, but that's much more sanitary that dealing with the black water from a toilet. The portapotti that I'll use is self contained, with its own 4 gallon flush tank and 5.5 gallon waste tank. I've tried out the process for emptying the waste tank into a plumbed toilet, and it's actually quite quick, clean, and, thanks to an odor-masking additive, doesn't smell disgusting. To refill the flush tank, I can just use the showerhead and hose. 

The brown box next to the water heater is the furnace for the RV. It uses propane for heat, and has a powerful electric fan to blow hot air throughout the van. Using the eight gallon propane tank under the van, it has a running time of 57 hours. The forums say it's very effective but noisy, and its fan can drain your battery if you don't watch out.  Also, like the water heater, it has a combustion exhaust vent out the side of the van, wasting some heat. For these reasons, I intend to have an auxiliary catalytic heater. This one comes highly recommended:

Catalytic heaters don't so much burn propane as react it with oxygen to produce heat, water vapor, and a bit of carbon dioxide. They have a long safety record of use in enclosed spaces. They don't use a fan, so there's no noise and no power drain. They don't have an exhaust flue, so they're very efficient. This will be my preferred method of keeping toasty, using the furnace only when I want to warm things up very quickly. I do have to work out with Sportsmobile how I can hook this portable heater up to the propane supply. I'll also have a portable electric heater along for when I'm hooked up to external power.

The white box at the right in the image of space beneath the couch is the power inverter for the van. A power inverter converts 12VDC from the batteries into 110VAC to run the microwave, the rooftop air conditioner, small appliances, and computer equipment. Sportsmobile uses a high quality pure sine wave inverter.


"Pure sine wave" means the voltage waveform matches what utilities provide and is compatible with sensitive electronic equipment. The inverter is rated for 2000 Watts - double what you find in some much more luxurious RVs. This allows it to run the microwave oven, and even the rooftop air conditioner, off of battery power. Nearly all other RVs require that you start up the generator to use these appliances. For reasons I'll describe below, I've chosen not to have a generator, so a good inverter is particularly important.

The Sprinter engine is diesel, but there are batteries to provide electrical power for lights and appliances when the van isn't connected to external power at a campground. The batteries are divided into two sets: the chassis battery and the house batteries. The chassis battery is like the battery that all gasoline or diesel vehicles have and is used primarily to start the engine. The house batteries power everything in the living quarters of the RV, and can also be used to start the engine if the chassis battery is dead for some reason. Both the chassis battery and the house batteries are recharged by the 200 Amp alternator on the Sprinter's engine.


This is a powerful alternator, and that's the reason I chose to do without a separate generator in my design. Generators add hundreds of pounds and thousands of dollars to an RV. I'm getting an option on my Sprinter that allows me to set the engine to idle at high rpm even when parked. At this elevated speed, the built-in alternator can quickly recharge the house batteries if they get low. Of course, they're also recharged any time I'm driving the van. In effect, the Sprinter engine will be my generator. Reports are that the engine is quieter than a generator, even at high idle.

The alternator is also the reason I've chosen not to get solar panels on the top of my van - at least initially. I did a calculation showing that a full day of charging from solar panels only gives the same amount of charge as running the engine alternator for 40 minutes. I expect there won't be many days that I don't take an excursion of at least 40 minutes in the van, so I shouldn't have any problem keeping the batteries charged. However, I am hedging my bets: I'll have Sportsmobile run the wiring necessary for solar panels in case I change my mind in the future. If I leave the van for a couple weeks to go on overseas travel, solar panels would be enough to keep the refrigerator running while I'm gone, without having to hook up to external power. Just for reference here's an example of solar panels on a Sprinter van:

The other items you see on the van roof, from back to front, are: the air conditioner, the vent fan, and the in-motion satellite TV antenna (which I'm not getting).

The capacity of batteries is measured in Amp-Hours, and typical RV house battery installations are 100 to 200 Amp-Hours. I'm doubling that to 400 Amp-Hours so I can run the fridge, lights and my computer equipment without worrying about running down. If I used the house batteries only to keep the fridge running, I could go for 5 days without recharging. However, it shortens battery life considerably to repeatedly use more than 30% of their capacity. Large capacity batteries mean large size and large weight. My two 200 Amp-Hour batteries will weigh 132 lbs apiece.


I was glad to find out Sportsmobile can mount them underneath the van to save space inside. The eight gallon propane tank that runs the furnace, water heater, and stove is also located under the van.

The last utility appliance to discuss is the rooftop air conditioner. I don't even have air conditioning in my house, so this seems like quite a luxury, but I plan to do a lot of my camping in the Southwest, and nothing can ruin a good night's sleep like stifling heat. My first line of defense against heat will be to stay away from it. I plan to tour northern states and Canada - and eventually Alaska - in the summer months, and roam the southern latitudes in the winter. When I can't, or don't want to, go north to escape the heat, I'll go up in altitude. There are plenty of parts of New Mexico, Arizona, and even California that are high enough to stay quite temperate during the summer. When all that's needed is a little cool off, I'll use the Fantastic Fan in the van roof to circulate outside air. That, in conjunction with van windows that open should provide relief in most cases. The windows that open (and have screens) are behind the couch, next to the shower, and beside the bed. The lower part of these windows opens out and up like an awning, so they can be open even in a rain storm. If I want a truly open air feeling, I can leave the side and rear doors of the van open; I'll have screen curtains to keep the bugs out.

The rooftop air conditioner will be a last line of defense against the heat. It draws a lot of power (2000 Watts) so hopefully I'll mostly use it for an initial cool off of the interior and rely on outside air after that. Because of the power draw, it's best to operate it when the van is connected to external power, in which case I may be a bit more liberal in its use. Information on the Sportsmobile website is a little ambiguous, but it seems that with the engine on high idle, the air conditioner can run indefinitely off of the alternator too. The website also says the engine will consume 1.25 gallons per hour to run the air conditioner. At current prices for diesel, that would be 40 bucks for a night of comfort, but it's still cheaper than a motel room. In my plan, the air conditioner is located midway along the van so it will cool the front and back equally. Its position is indicated here, above the microwave oven:



That completes our tour of the rooms in my Sportsmobile design. If you've read this far, you must be genuinely interested in all the little details. So, as a reward for your persistence, I direct you to a video tour of a completed Sportsmobile conversion. A few notes about the video before you go: The van is the same size and color as the one I'll be getting, though the floorplan is significantly different. To toot my own horn a bit, my plan fits in all the features you see in the video plus a couch that doubles as a bed for two additional people. Also, my design will have more windows and feel a lot more open than the design shown. The guide in the video is Jonathan Feld, the President of Sportsmobile West and the designer I've been working with. It was the demonstration in this video of what's involved with emptying the waste tank that influenced me to go with a portapotti instead. Also, the furnace and stove in the demo van run off diesel fuel which requires the complicated procedure you'll see; my propane appliances are much simpler to operate.

Though our tour of my planned RV is done, I've saved some fun for last. Being an electrical engineer, I've got to have a good supply of gadgets along, and those will be the subject of my next post.


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