question: modifying existing motorhome LP gas system

Greetings.

I'm considering changing the existing LP system to reduce vehicle weight.

I'm heavily modifying a 2006 Itaska Navion 23J (Sprinter 3500) to use in South America and Europe. Weight is becoming increasingly important as I've added numerous systems, like B2B and shore chargers, solar, etc. I implemented mods to reduce its LP consumption, including changing the LP furnace to diesel, LP referigerator to DC power, and generator to gasoline (Honda 2000 set up to burn either LP or gasoline). The remaining LP use is a 6 gallon atwood water heater, outside grill and an inside cooktop (3 burner). I have a digital T-stat on the water heater and turn it on just to use it. I estimate my consumption to be about 1 gallon per month.

As is, the motorhome has an 18 gallon (14 usable) fixed tank (ACME 1 3/4"),(2) 2-stage regulators (house and generator. It had an Onan 3.6Kw LP generator that I removed), and about 30 feet of 1/2" steel piping bracketed to the underside of the vehicles 5" flooring. Steel pipe turns to copper under the floor near the floor penetrations.

I'm thinking about substituting a 20# bottle for the fixed tank, perhaps even an aluminum bottle, and using only 1, 2 stage regulator at the bottle. Also, a bottle has major practical advantages in terms of getting gas in foreign countries. Having a fixed tank, in comparison, can be a PITA, but doable.

Question: Can I eliminate the existing steel piping and replace it with typical copper tubing? It's inconceivable to me that the copper line could be damaged, because the underside of the floor system (where the copper pipe would be installed generally) is behind so much other structure. The floor system rests on aluminum I beams. Obviously, using steel is a US code requirement. I'm just wondering if violating that could make sense, given that I'd save weight.

This is just an idea. I'm still assessing, but it might have a net weight reduction of 60 pounds.

Thoughts? Thanks
 
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sparkplug

Well-known member
Can't comment on the steel v copper aspect, but I do know that bottles in Europe have different connectors in different countries.

You will probably struggle to exchange bottles from one country in another and many bottle suppliers get you to pay a deposit on the bottle when you buy one without an exchange.

You can buy Euro adaptor kits which you will probably need to connect to your gas line.

This is the reason why I've chosen to have a fixed underslung tank which you can refill at any fuel station that sells LPG

Simply use https://www.mylpg.eu/stations/ to find places where you can refill.

Just my 2c....
 
Can't comment on the steel v copper aspect, but I do know that bottles in Europe have different connectors in different countries.

You will probably struggle to exchange bottles from one country in another and many bottle suppliers get you to pay a deposit on the bottle when you buy one without an exchange.

You can buy Euro adaptor kits which you will probably need to connect to your gas line.

This is the reason why I've chosen to have a fixed underslung tank which you can refill at any fuel station that sells LPG

Simply use https://www.mylpg.eu/stations/ to find places where you can refill.

Just my 2c....
Thanks! South America is first on the list later this year. The underslung fixed tanks aren't as friendly down there. Often, you have to get a "driver", willing sometimes to bend procedures, to meet you somewhere because the trucks have the ability to fill your tank. Not impossible, just a PITA.
 
To follow up and after reviewing the BTU calculations, I decided to eliminate the fixed (underslung) tank and all steel piping fastened to the underside of the motorhome's floor. I plan to replace the original equipment with a new 30 pound horizontal cylinder bottle installed in a air tight compartment above the floor line, thus I'll be using copper lines only. Everything will be in the heater envelope now, so hopefully this will work better in cold temperatures.
 

Midwestdrifter

Engineer In Residence
Having it inside the heated space will help. Make sure not to insulate the compartment walls between the heated space and the locker, that way you get some heat pass through.
 
Having it inside the heated space will help. Make sure not to insulate the compartment walls between the heated space and the locker, that way you get some heat pass through.
Good thought. I had installed vents through the 1/4" walls of the compartments and around under the shower. Basically, I wanted passive ventilation to avoid winter condensation/ mold issues. The tank compartment will be right under my bed.

Also based on your comments, I bumped up my tank size from a 20# to a 30#. Thanks for the nudging.
 
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Air tite to the cabin and very vented to the outside?
Yes, absolutely. Thanks. I am making design mods to the system and cylinder compartment to suit my needs, but am following the conceptual plan and specs that I found here: https://faroutride.com/propane-system/

Based on my BTU uses, a 20# cylinder would last about 8 weeks. I upped this to a 30# cylinder to add extra contingency in the event I have to run my Honda 2000 generator on propane for long periods. It's unlikely I'd run the generator much at all, since I have 575 watts of solar and a 60 amp B2B charger and 200 amp alternator. The Honda burns LP or gasoline, but the extra LP is a cushion.

The cylinder comes with a gauge attached. I'm looking now into a practical, and simple, way to monitor the cylinder level from inside the campervan. If I can't find a reliable monitor, I'll install an 8 x 8 plexiglass panel into the wood end panel of the cylinder compartment, so I can look in and read the gauge. I just have to go outside and open the compartment to read it.

I also intend to omit a solenoid shut off valve due to power consumption opting instead to just use the tank's manual shut off valve when appropriate.
 

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Midwestdrifter

Engineer In Residence
If you have freezing issues with the tank, you could rig up an electric heater for that tank easily/cheaply. I personally wouldn't worry about it too much. You have a diesel cab heater, so worst case you can't have your morning coffee.
 

Midwestdrifter

Engineer In Residence
That still requires many thousands of dollars in lithium batteries, more solar, etc. All of which still have temperature regulation limits. Heating water with electricity is quite energy consumptive as well.

The OP also wants to operate year round in areas that may get minimal sun exposure, and plugging in is a nonstarter for high power needs. Mostly due to various grid voltages, power surge concerns, etc. Given that he already has the propane systems, simply changing the tank seems like an expedient and cost efficient method.
 
If you have freezing issues with the tank, you could rig up an electric heater for that tank easily/cheaply. I personally wouldn't worry about it too much. You have a diesel cab heater, so worst case you can't have your morning coffee.
No worries. It's under my bed and inside the heated envelope. This should work out pretty good and reduce weight 110#, so I can carry more beer!!!!!!!!
 
Man if it were me I would consider converting over to 12v systems and dump the gas.
I've been modifying a little motorhome. Making a tuxedo out of a pigs ear.

I'm doing 14-16 months in South America. If I keep this rig, I'll add lithium and loose the gas if it makes sense, although I like gas for cooking inside and outside the rig. As it is, I've reduced gas consumption greatly since buying the rig by ditching the lp refer for a 12V refer, changing the lp furnace to a diesel espar and exchanging a 3.6Kw lp Onan generator for a 2Kw Honda 2000 (burns either lp or gasoline). I added a split, 2 MPPT controller, 575 watt solar system with an inverter.

These phase 1 mods allowed me to dump the 60# underslung tank, 35' of steel piping and get the equipment into the rig to avoid freezing, plus I save 110# net weight reduction. Additionally, filling this bottle will be MUCH easer than the fixed 1 3/4" ACME tank.

But, beyond this, phase 2 gets expensive until I know I'm keeping the rig. I only have 260AH total (130Ah usable) in an AGM battery bank, so I'm doing what I can within this constraint.

Systems are built/sized to accommodate 300-400Ah of lithium. That's phase 2, or I'll punt and start over with a bigger, larger hole to drop money into. :smirk::smirk:
 
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OrioN

2008 2500 170" EXT
Man if it were me I would consider converting over to 12v systems and dump the gas.
I have a propane system. It runs the fridge, genset, cooker.

I have 400aH of Li batteries, 1200 watts of solar, 105A of Genset, 150A shorepower charging and 70A alternator charging.

I would never consider abandoning propane. Redundancy is key, so is the ability to create electricity when I am not driving or there is no sun/shore.
 

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