Major RV Systems

1 Mar

In May we rented a 30′ RV from Cruise America.  The RV was a very typical Class C Motorhome. It had 12vdc power supplied by a house bank of probably AGM batteries.  I believe there was a very small inverter to run the 110 outlets in the cabin for small loads like computers and phone chargers.  The lights were all 12VDC. The fridge was an RV type three way fridge powered by either 12VDC, 110VAC, or propane.  The heater was propane powered, and there was a gasoline powered generator which was needed to run the roof mounted AC and the 110VAC microwave.  So then when plugged in to shore power at a campground the 110VAC would power the fridge, microwave, AC, and recharge the batteries.  The alternator in the gas powered Ford E-450 chassis also was able to recharge the battery.

There was a 30 gallon or so freshwater tank, but since it was a rental and we couldn’t guarantee what had been in the freshwater tank they recommended only bottled water for drinking, cooking, and cleaning, which was pretty easy on our trip.  The RV also included a grey water tank to catch the sink and shower water, and a black tank for the toilet.  There was a very small propane fired hot water heater which held about 6 gallons of hot water, but took a while to heat it up, but it also meant the showers needed to be quite short and to the point.  Our ability to boondock off the grid without being plugged in was limited primarily by the size of our holding tanks.  Maybe we didn’t plan enough in advance to figure out how to economize our water usage but we would run out of fresh water at about the same time that both our grey and black water tanks were filling up in what took about 2 nights / 3 days.

For a rental RV in the US with our national highway network and installed campground user base and culture, I think this was very appropriate.  For what I want to do, I don’t think it is going to cut it and we end up getting further into the definition of what an expedition vehicle actually is.

As soon as you get into the realm of a Class 5-6 chassis like the Freightliner M2, weight requirements and restrictions become greatly minimized due to the GVWR of these larger chassis’.  To that end, fuel tanks and holding tanks can be typically much larger.  Also, on the electric side, there’s a lot more capacity for a bigger battery bank for more off grid power.  What I would like to see is an entire roof of solar panels recharging a very large bank of Li-Ion batteries (ideally a Tesla Battery pack!), enough power and regeneration that we won’t even need a generator.  The whole system could  be run by a Mastervolt type control system for charging, recharging, and using power.  On the water side, I would like to see a water tank and filtration system that can pull from any source (including rooftop rain collection and nearby streams – hopefully using filtration like a Slingshot) and filters it enough to fill the fresh holding tank.  Then the grey water tank could be put through the same filtration system and put back into the fresh tank.  As for the black tank, ideally I would like a flush and forget type system like an Eco-John WC5-Mini.  With the EcoJohn, there would be a very small black tank that would get macerate and then incinerate the waste so you wouldn’t ever have to dump a grey or black tank at all, other than sweeping out the ashes.  On their larger models the incinerator is diesel powered as well.

That leads to the inside appliances.  Most internationally driven expedition vehicles are not equipped with propane as there’s no global standard for supply and delivery or quality.  So every country has their own standard of fittings and laws governing filling, refilling, using propane and trying to find the right adapters and sources seems to be a pretty big hassle.  As a result most all appliances are electric or diesel powered.  The refrigerators are typically driven with a DC compressor rather than the normal RV three way systems.  Not only are they more efficient than the adsorption style three ways, but they are also able to operate on a sloped surface up to 15deg, whereas the adsorption models can’t tolerate more than 1/2 degree of tilt.  Beyond the fridge, Webasto and Espar are companies who both make diesel powered heaters and hot water heaters for mobile RV applications.  With a hot water heater, Main Cabin heater, and Toilet Incinerator all diesel powered, they would pull fuel from the main diesel tanks not requiring a supplemental propane tank or the worry about filling said system around the world.

The other appliances would then be electric, either designed for 12vdc power or run through the Mastervolt inverter system.  I would like to see an electric induction cooktop, an electric convection oven, electric drawer dishwasher unit, and an electric combination clothes washer/dryer.  Basically all of the comforts of home as this will in fact be our home.  Of course with all of those electric appliances as well as usual assortment of lights and chargers and a nice flatscreen TV, electric lifting roof and hydraulic pump for the rear tire rack we will need a LOT of power.  That’s why I believe the deeper power cycle of the Lithium Ion cells with larger number of cycles than standard AGM batteries would be required for our rig.  Hopefully within the next few years before we begin building Tesla will have the Gogafactory up and running and have announced and started shipping their home battery storage devices, and we’ll be able to incorporate one into ROAM.  It would only be appropriate as the only way I’ll be able to afford to build this rig will be when Tesla stock hits $400+ in 2016!  Then we’re all in baby!  My intention here was to cover all of these RV and XV systems in this blog post, but I believe I will probably need to devote a new post for each of these subsystems.