Mikey's Sprinter Expedition Camper: Systems

mhiscox

Expedition Leader
After an indefensibly long delay, it's time to start wrapping up the build thread on my Sprinter camper by covering the systems in the van.

The chassis and exterior, along with an overview of the vehicle, were covered first in the thread at:

http://http://expeditionportal.com/forum/sh...ad.php?t=19224

The thread that covered the cab and interior is at:

http://www.expeditionportal.com/forum/showthread.php?t=20079.

The easiest place to begin coverage of the camper's systems is at the rear, since most all of the system have some connection to the rear "mechanical room."



The idea of a mechanical room is admittedly somewhat obvious, but I got really serious about it once John Speed discussed its advantages in Travel Vans. And now that I've used it for several years, I think it is an excellent concept. Unlike, say, my Unimog, where, propane is in one place, CO2 in another, water fill in a third, camp chairs in a fourth . . . it's very nice having everything you need to deal with all in one spot. But there are a few benefits you might not think of. For example, separating the big Outback inverter from the living area is a plus, since bigger inverters can make some noise. This layout allows an easy way to see the level of the water tank, letting you fill it to any given capacity without guesswork. And things like spare parts can rattle around some. Somewhat more obvious--and more important--is that the propane and petrol-fueled generator are outside the living area.

The easiest way to show what's going on is to show the mechanical room's contents piece by piece. First is the on-board air system, which lets me deflate the tires for off-pavement use and then get them reinflated when I get back to the tarmac.



It is a ten-pound tank of compressed CO2 held in a bracket sold as part of the system mounted to a shelf over the fresh water tank. The tank is easily removable for remote use; just pull a hairpin clip and move a handle. Besides the tire chuck usually connected to the yellow hose, I also have a bag of other air things, like an inflator that could fill an air mattress and a triggger gun that I can use to blow things off.

The fresh water tank is custom made of plastic to hold 50 gallons. It is filled as simply as sticking the fill hose in the opening covered by the screw cap. You can see the water level through the translucent plastic, and thus if you want to carry less than the full amount, it's easy to stop at any level. And, of course, it's nicer to just stop filling when the tank is full than to have to wait for the water to overflow the tank to know it's full. The tube next to the filler is a vent.



Incidentally, while it makes no difference given where I travel, I'm sure that there are sufficiently adventureous places where there'd be a nice security advantage to having the fresh water tank and fill locked up tight.

The Honda eu2000i generator is stowed in the far back passenger side area of the mechanical room. This is not any sort of fixed installation. When you want to use the generator, you pull it out of the compartment and sit it alongside the truck.



Lots has been written about the benefits of the little Honda generators in terms of portability, quiet, and reliability and I second those positive comments. One thing relevant to some campers is that this unit cannot generally run RV air conditioners, but it can run the window-style AC in the Sprinter and the identical unit I have in the Unimog can usually run the smaller-than-normal (7800 BTUs) Coleman Polar Cub rooftop air conditioner reliably. (Not always workable in the triple-digits.)

The generator tucks under a cabinet space accessible from the interior. The back (rear) is now covered with a piece of thin plywood, but it was originally open to the mechanical room.



In the original configuration, this space was used for a pretty elaborate AV system with an NAD integrated amp, Anthony Gallo speakers and subwoofer, etc. While it sounded great, the whole thing was a bit over the top for a vehicle like this. The space is now open storage, whereas it started out as an AV component cabinet designed so there'd be some air space at the rear.

Along the passenger side wall, I've fastened a sturdy nylon mesh bag that holds a fluorescent battery lantern, power cable adapters and a good-sized Kelty Noah tarp.



There's also some light rope and a handy fabric ground cloth that I picked up somewhere. It's surprising how offten it comes in handy, either to lie on, sit on or cover something (like a picnic table). Here's the stuff routinely carried in the bag:



Next to the bag, in front of the generator, I carry four plastic boxes as sort of a "parts depot." One is dedicated to electrical stuff like fuses, another to emergency stuff like flares, space blanket, etc., and a third to "patching" stuff like tapes, glues, epoxies, wire and cable ties. The last just holds rags and different sets of gloves, including disposable rubber gloves. Next to the bins is a set of mechanics tools--sockets, wrenches, pliers, etc.--in a blow molded case. Not really heavy duty, but a wide variety of tools in both metric and standard and good enough for infrequent use.



To the right of the tool kit you can see one of the three large house batteries. The other two batteries are in the interior under the smaller seat cushion. Each battery is a 12V AGM battery that's nominally 210 amp-hours, so that's about 630 for the truck. If you use the "maximum 50% discharge" rule, that means there's 315 amp hours available. (Of course, that's both theoretical and when they are new. Actual performance is less.) The batteries are a different form factor from normal, plenty tall and long, but just 5 inches wide. All in all, about a 40% reduction in volume for the capacity. They look like this:



My batteries were sold by Meridian, and I don't know that the company is still around. However, they were likely made by someone else (maybe Enersys, not sure) and they are still available under a different brand name.

We have room in the comaprtment to carry a portable electric heater. That might not seem sensible, given that there are already three heaters available (one diesel, one propane, one electric) but this particular unit by Vornado has some advantages.



It can be aimed at someone, which isn't true of the other three units. Equally nice is that it will vary its heat output as needed, so that when it's almost warm enough, the heater is putting out air that's not real hot. And probably the most interesting use is when we have a tent along with us to sleep another person or two and we can put this heater, which can't set anything on fire, in the tent and power it with an extension cord from the Sprinter. (And in the summer, we swap the heater out for a Vornado fan of approximately the same form factor; the fan is variable speed, quieter than, say, the Fantastic vent fan we have, and a workable alternative for the air conditioning at lower temperatures.)

That's enough for now. I'll do another post to cover rest of the mechanical room components in the next several days. Let me know if you have any questions.
 

Stumpalump

Expedition Leader
You will love that 50 gallon water tank. I just just returned from a week in Moab and was surprised how fast I blew thou my 19 gallon tank. 1 Zodi shower, two sponge baths and a hair wash, plus dishes and it was gone in 5 days. I'll be a little more careful next trip but I could easily see 50 as a nice amount on an extended boon dock trip. I put some bleach in the tank to sterilize but I think I'll measure real carfully and only put in about 4 tablespoons next time. Does 1 tablespoon per 5 gallons seem right or can I go with less? A little bleach seems strong especially since I'm used to well water. Nice Van!
 

mhiscox

Expedition Leader
I put some bleach in the tank to sterilize but I think I'll measure real carfully and only put in about 4 tablespoons next time. Does 1 tablespoon per 5 gallons seem right or can I go with less? A little bleach seems strong especially since I'm used to well water. Nice Van!
Glad you like the van.

If you are getting the tank ready for known-potable water, the RV wisdom is 1/4 cup per 15 gallons. 1/4 cup is 4 tablespoons, so you hit it spot on.

FWIW, the common approach to disinfect drinking water is one-eigth teaspoon (which is eight drops) of household bleach per gallon of water, which means that, at least theoretically, about two full teaspoons in fifteen gallons. I don't mess with this in the Sprinter because I have a Seagull canister water purifier, but it's worth knowing for the other trucks.
 

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elysium

Observer
Lots has been written about the benefits of the little Honda generators in terms of portability, quiet, and reliability and I second those positive comments. One thing relevant to some campers is that this unit cannot generally run RV air conditioners, but it can run the window-style AC in the Sprinter and the identical unit I have in the Unimog can usually run the smaller-than-normal (7800 BTUs) Coleman Polar Cub rooftop air conditioner reliably. (Not always workable in the triple-digits.)
I should have noticed earlier, but reading your section on the generator made me realize that you have a window-style AC unit in the middle of your sprinter. Out of curiosity, how do you vent the heat from the AC? I noticed in some of the construction photos that there is a closed box for the AC unit. Is there a side or bottom exit from that box?
 

mhiscox

Expedition Leader
I should have noticed earlier, but reading your section on the generator made me realize that you have a window-style AC unit in the middle of your sprinter. Out of curiosity, how do you vent the heat from the AC? I noticed in some of the construction photos that there is a closed box for the AC unit. Is there a side or bottom exit from that box?
There is basically a two-section plenum aft of the unit. The AC puts the hot exhaust air out the back and draws inlet air from the sides. So the trick is to get the warm air out without it mixing with the inlet air.

In the first iteration, I'd selected a 7500 BTU Panasonic unit and the vent was a sliding panel in the van floor. But there was too much air mixing. When that happens, not only doesn't the AC cool anything, but the current draw will become excessive as the unit tries to cool ever-warmer inlet air.

Thus a more complicated plenum had to be built. Unfortunately, with the propane locker where it was, the Panasonic AC was too deep to give enough room. So it's on a shelf and a 30% shorter 5500 BTU Sharp is now used. That left room to build inlet and exhaust sections and have independent inlet and outlet vents. I also added a small Flexlite automotive electric radiator fan for the exhaust air that is wired to the compressor switch, so when the unit wants to cool, the warm exhaust air is fan-forced out. The outer holes are connected to tubes that bring in cool inlet air.

Here's a picture:



but if you're interested, the whole problem, problem solving and result are in a web album that I'll leave public for a while at:

http://picasaweb.google.com/mhiscox01/SprinterAirConditionerExperiments.

The 5500 BTU unit works quite well, but it is a little under-capacity for the very hottest days. On the other hand, the thing is quiet, efficient and only draws between 500 and 600 watts, so it is an easy load for the generator and can even run off my battery bank for a few hours if necessary.

Post up any more questions you might have about this.
 

dzzz

Not directed to mike, but to point out there are sleeper cab A/C that are not roof mounted. The units sits inside and vents through a typical RV wall vent.

A while back I was interested in a sprinter build. 5500 btu is pretty small. Especially for the evening cool down while it's still hot outside.
 

mhiscox

Expedition Leader
Not directed to mike, but to point out there are sleeper cab A/C that are not roof mounted. The units sits inside and vents through a typical RV wall vent.
Don's right about it being worth checking whether a truck cab unit will do the trick. The problem I found was that the self-contained units were even smaller BTU-wise and the larger units also needed space for a seperate compressor unit. Worth a Google search in any event.

A while back I was interested in a sprinter build. 5500 btu is pretty small. Especially for the evening cool down while it's still hot outside.
Yeah, but it beats the heck out of no air conditioning. ;)

More to the point, though, it works partly because of the white van and reflective shades, partly from living in Oregon rather than Arizona, partly from the curtaining off of the front cab area, and partly from running the air conditioner off the inverter while driving in the afternoon. With a 200 amp alternator, whenever the engine is turning, it's easy to keep the batteries full up, even when running a load like this AC. Therefore, the rear of the cabin is kept at a reasonable temperature, rather than the unit having to lower the temperature twenty degrees once parked.

Also, figure if the cabin (6 feet wide by 10 feet long) were a room in a house in Oregon, it would take just about 1500 BTUs to cool it. The Sprinter's not a house (three walls are "outside" walls) but it is insulated and has double pane windows, so I'm happy enough with my 5500 BTUs.
 
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