Propane Precautions Especially For Long Term Storage Situations

[Geronimo John]

There are many posts on our forum about our life safety detection systems and consequences of what can happen when things go badly.  For this post, I am trying to highlight one simple step that each of us need to do when leaving our Oliver unoccupied and unattended for extended periods of time.

But first, some info about propane.  Both of the LPG gases, propane (C3H8) and butane (C4H10), are heavier than air.  Propane is about 1.5 times heavier and butane is 2.1 times heavier than air.  In a stagnant air situation, they will pool at the lowest level they can reach.  Good news is that propane will only ignite within their upper and lower explosive limits (LEL). Said differently, the lower explosive limit is the lowest possible concentration of a gas that will burn or explode if ignited. The upper explosive limit, is the highest possible concentration of a gas in the air which will burn or explode if ignited. 

So, keeping your life safety detectors in good working order is an imperative.  Doing so gives us great protection when using Ollie. However, the purpose of the below is to call your attention to a potential hazard that most of us have not likely considered…. What about when we are gone for months?

 BLUF (Bottom Line Up Front):   It is imperative to shut off the propane tank valves and totally kill & secure the power to your trailer if it is left unattended for long periods of time.

 Scenario:

You are going to be away from your Ollie for several weeks or months.  Unknown to you, there is a super small propane leak in your Ollie.  It is so insignificant that it does not set off your propane detector.  For long duration storage, to minimize battery losses, you have turned your master 12V electrical switch to “OFF”.  You have removed and secured the shore source and power cord.  So electrically your trailer utility wise is dead.  But, this time you forgot to turn off the propane tank valves and did not place the propane auto switch-over in the center position.

 In your absence, the small leak continues to leak.  Eventually, it it pools in a low space and continues to grow.  Eventually it exceeds the LEL for propane.  For the fire/explosion triangle, you now have fuel and oxygen.  But since there is no ignition source, no fire/boom. 

 Weeks or months later you return to Ollie.  You pull out your Arrival Check List and proceed to uncover and unlock Ollie.  You carefully check for wasp/hornet nests as you carefully open the door.  Then you open up the trailer windows.  With your flashlight, you check all areas of Ollie for things that may have changed in your absence.  Things like pest intrusions, leaks, spills, canned food or wine bottles that froze hard and then leaked, or any of a host of other things that can happen while you were away.    

Part of  your Arrival Check List process is to open up the hatches and look there too.  When all looks good and you do not smell any weird smells from the above sources, or the distinctive “rotten egg” smell of mercaptan (The propane mal-odorant), you turn on your 12 Volt master switch to power up the trailer lighting.  Another quick look...all is good.  Then you fire off the Max Fan for fresh air, and you can safely connect up to shore power.  Next you turn on the refrigerator and A/C.   Miller Time!

But this year, a family member is the first to Ollie and they have just a bit of trailer experience.  Their first mistake is not to follow your Arrival Check List, but instead they plug in Ollie to shore power.  Boom.   

So, for long duration unattended time frames, please ensure that you make safe your propane system by isolation from the tanks and killing the 12 and 120 volt shore power systems by turning them off and locking up any means for them to be activated until you have inspected your trailer for unknown hazards.

Mahalo,

GJ

[MobileJoy]

For long term storage I follow the Lithionics battery maintenance procedure for 130Ah batteries. The choice I use is to leave the batteries on, turn on the heating pads, and connect an external (Lithionics) charger to the batteries. The shore power inlet remains disconnected. All major appliances, the solar panels, and the Xantrex are turned off but there are still some parasitic draws like smoke alarms that I do not stop. Although 20 miles away from home I visit Mojo at least once a month and usually more often. As part of my departure checklist I always make sure the propane cylinders are turned off (two pairs of eyes are on this), and I recheck the valves with each visit. The Mojo is stored in an enclosed unheated unit with a garage door.

Although I do not currently do this, I could turn off the master 12V switch if there is one, but this would not prevent some electrical switching in the battery compartment. The batteries remain on for maintaining charge. Given that the tanks are off, propane leaks while in storage haven't concerned me until now.

To properly maintain the batteries without a charger, they have to be removed if they would otherwise be exposed to freezing temperatures. Since we do have occasional freezing periods here, I purchased the charger so I could use the heating pads, preventing the batteries from freezing.

So, GJ,  given the storage procedure I use, is there anything else you can think of that I could do to increase propane safety?

[Geronimo John]

MobileJoy:

Concerning your Lithionics batteries:  Each manufacturer has their own winterization procedures to follow.  Some, like Battleborn have different procedures depending on how deep of a freeze your location could experience and how long your absence will be from the trailer.  So I recommend that you DO follow your MFG's winterization process.  If you situation is unique, such as my Battleborn's, with my 8 month absence from the trailer, and wintered where they can see a -5 degree F temperatures for up to a couple of weeks at a stretch; then call your MFG and discuss your situation with them directly. 

Regardless, I recommend not having your propane system active for any long term non-attended storage.  

If you don't have a master 12V on/off switch, I would strongly consider adding one.  With lithiums for normal winter storage (say 3 months), the parasitic losses are typically not significant enough to worry excessively about.  But having a BlueSeas 350 amp master switch sure lets me sleep better when away for so long.  Not to mention the ability to turn off all battery power very quickly should we smell smoke inside the trailer....   It's just a good idea and an easy DYI add.  See Max Burner's post about the install we worked on this past summer.  

9 hours ago, MobileJoy said:

To properly maintain the batteries without a charger, they have to be removed if they would otherwise be exposed to freezing temperatures. Since we do have occasional freezing periods here, I purchased the charger so I could use the heating pads, preventing the batteries from freezing.

Your statement is correct for most Lithiums that need to be charged/discharged during winter extreme conditions.  The use of heated batteries allows one to charge and discharge their system at will.  However, if you don't use your trailer in extreme freezing conditions, then you don't need to worry about use of the batteries because they are shut down at the master switch, or in come cases by button's on each battery.  Such is my case and many others.  So having the heaters is good and necessary for the Cold Weather Owners for sure, and generally not for most other owners.

One other option for fringe weather owners that use their lithium battery powered trailers in early spring and later fall where they may get short periods of very cold conditions.  By installing a cabin air ducted fan system to the Litho battery box, (Such as John Davies and others have documented), you could get by without the expensive battery heaters.  There is also some benefit to having such mods during extreme hot weather conditions to help keep the battery box temperature closer to the interior temp of you Ollie.    

 Best regards,

GJ

[MobileJoy]

Sorry, I did not mean to turn this into a discussion about batteries. I only mentioned the storage procedure I use (recommended by Lithionics) to indicate that I do have electrical switching going on in the battery compartment. Without an added battery box circulating fan, I do not see any leaking propane finding its way in there. With the tanks shut off, I do not see small propane leaks as a storage issue. I do understand your points about unique circumstances leading to lower explosive limits being reached. For us, we do not provide unsupervised access to our trailer to anyone else, we religiously make sure the tanks are off when in storage, there is no available shore power at our storage location, and I don't think we have a master DC cut-off. The Lithionics batteries can be turned off, but then they would have to be removed for cold weather.

I will look into adding a master DC cutoff switch. This would kill all power to the trailer while allowing me to leave the batteries and heating pads turned on. GJ, a big thanks for this advice!