How to keep jerry cans from freezing when boondocking?

[profdant139]

We just got back from a week in the Sequoias -- great fun, lots of snow, good snow-shoeing. One night it got down to 11 degrees, freezing the water pipe leading from our fresh tank to the pump. (It thawed later in the day and we had no further problems, with the nights in the 20 degree range and the days in the mid-30s.)

We also had lots of extra water in our 6 gallon plastic jerry cans, which were stored outside (of course), since our trailer is so small. They froze solid, too, not surprisingly.

So that is my question for you experienced snow campers -- I understand that I can't rely on my big fresh water tank in really cold weather. We are happy to rely on the jerry cans, heating up water for sponge baths on the stove. But how does one keep the darn jerry cans from freezing?? (Heat tape is not the answer for us -- it uses too much juice, even with solar power.)

Thanks in advance for your advice!

[garyhaupt]

I am hurt Dan...you acknowledged all but me. You California guys are sure touchy.

When I typed KISS...you did realize that's an acronym, right?


Gary Haupt (=)

[pianotuna]

Hi,

led's do produce heat--just not as much as an incandescent bulb. But I agree, for freeze protection they are not desirable.

PRodacy wrote:


Forget the LEDs. They don't produce heat.

[PRodacy]

profdant139 wrote:
We tried putting the jerry cans into the back of the truck -- they froze there, too. And we had a cooler in the back of the truck -- we took all the food out of it but left water bottles inside. They froze.

I like the idea of bringing in one jerry can and leaving it just inside the doorway -- that is all we would have room for. No way we can put a can in the shower -- there is no room. In our trailer, the shower is the toilet, too!

A couple of years ago, I enclosed the area that froze (the low point of the tank, where the outflow tube is attached), and that area is wrapped in reflectix. That method was adequate when the temp was around 20 degrees, but not at 10 degrees.

I am thinking about creating a fully enclosed air space around the tubing, with an LED panel inside that space. The "dead air" zone around the tube would be small. The LED would give off just enough heat, I think, to warm the trapped air just a little, enough to get us through the night without freezing. (I could easily monitor the temp with my remote thermometer, which I now use to monitor my backyard smoker!)

I would power the LED by tapping into my 12 volt system, with a switch. It would not draw much power -- maybe 300 milliamps. The only trick would be to remember to shut it off in the morning!!

Forget the LEDs. They don't produce heat.

[profdant139]

Camo, I have been looking at various sources since I saw Dave's suggestion about tapping into the heater. In larger RVs, you are right that there is a big box where the hoses are connected -- that box is the plenum, I think. Unfortunately, my RV is so small that there are no hoses -- the heater is a little box mounted under the stove. The air comes from outside, blows through the heating element, and goes directly into our interior space. This is called a blow-through heater, not surprisingly, and it is the most primitive kind of RV heater.

I need to somehow gain access to the heater and see if there is a way to create a plenum to which I can attach a hose, all without creating a fire hazard! Your suggestion about metal hose is a good one -- mice can chew through almost anything, as I have discovered to my sorrow.

[SteveAE]

A heat pump would use way too much electricity. They are also not very efficient when it is cold out.

I suspect a LED bulb would not generate enough heat. An incandescent bulb might. The heat pad that I posted the link to earlier generates about the same amount of heat as two incandescent bulbs would. Better yet though, you could tape or glue it right to the area that froze so it would be in direct contact with the problem area, then insulate over top. If you used a light bulb, the heat would be more point source (pinpoint) and there will be space between it and where you want the heat reducing efficiency (and difficult to insulate).

If your furnace has multiple heat registers, there is a good chance you have a plenum chamber. A Plenum Chamber is simply a sheet metal box that all the duct work attaches to. The heat from the furnace goes into the box and is then distributed to all the ducts. You can probably add another duct to the plenum either via an existing knock-out or by drilling a (large) hole into it. Then run that duct into the space that you want to heat. Of course that space needs to be closed off (insulated if possible too) so the heat doesn't just disappear into space. And you need a reasonably route from your plenum to the area that froze.

You also could simply install a short powered duct (with a fan) from the cabin (preferably a warm spot in the cabin) down to where you need the heat. Then just turn on the fan when you want heat down there. Disadvantage of this and above suggestion is you have to keep your cabin warm (probably 60 or better) to compensate for heat loss.

You also could move the water around, so it doesn't set too long in one place, with a recirculation system. And several of us have discussed (and built) such systems on this forum.

A sneaky way (and what is working well for me now) is an indirect method if your trailer layout allows such. I installed a radiant propane (Wave 6) heater (uses no electricity) in the trailer where it also warms the floor right above the water tank. The floor gets warm (not hot) and heat is conducted down to the tank, the top of which is pressed tightly against the floor. Presto, the tank gets some (not a lot, but it doesn't take much) heat.

One last suggestion but your wife won't like me for it (-:
When I snow camp (in a snow cave or tent), I take my water bottles to bed with me. Usually works well in all but the most demanding conditions (I did have one start to freeze once.....) Of course, I am only talking about two or three 1 liter bottles, not a whole 5 gallon jerry can.....

[Camorhino]

Your heater usually has a metal box with knock outs where the flexible hoses hook to while routing to areas of your trailer. Though they are usually a larger diameter than what you would need for for your project. You should be able to find smaller diameter flexible metal hose and accoutrements to mount to that plenum at the home stores. IIRC, a bath room vent fan uses the smaller hose, and there are kits to install those with just the hose and such. I used dryer vent hose to extend a vent into the bath of my trailer. Use the better metal hose if you are extending outside to the elements, as mice can chew through the cheap stuff.....

[profdant139]

Dave, that is a very interesting idea! It sounds like you know a lot more about how the heater works than I do. Would you know of a link that discusses how to tap into that plenum? I am sure that I could fabricate an enclosure for the vulnerable portion of the tank, and it would be pretty easy to run some sort of duct to that point.

[dave17352]

On my lance TC the heated enclosed holding tanks are made that way with nothing more that a plastic housing bubble that encloses both tanks. They run one heat run to it with flex duct and then put a vent that comes inside the camper so the air can circulate. It works great. Your furnace should have small plenum on it where you can connect small flex duct. Just a thought. Maybe doable. It would sure be great to be able to use your fresh water tank. Of course any type of rigid foam strapped out side that bubble would help also.

[time2roll]

Very much the same and not practical. Yes some RV air conditioners have heat pumps.

[profdant139]

OK -- I'll bite -- what is a heat pump, and how much current does it draw? Sorry for the newbie-style question -- I have never heard of an RV heat pump. I have heard of home air conditioning systems that use heat pumps, but I am guessing this is not the same thing.

[time2roll]

+1 to keep one water container inside. The other six can remain frozen until needed.

Infrared LED is still just resistance heat. Need a heat pump to gain thermal efficiency.

[profdant139]

Steve, that is interesting!! Piano, I had no idea they made an infrared LED -- I will check that out. The LED lights inside my trailer do put out some heat -- not much, but it might be enough, especially if the panel is designed to emit infrared.

And Dave, there is a propane furnace, but I don't have a way to vent it to the underside of the trailer. Can you think of a way to bootleg some of that heat to the tanks??

I should add that given the extreme temps, we used the furnace much more than we ever have before -- with a 120 watt solar panel, we now feel like royalty -- "sure, turn on the heater -- so what if the furnace fan is an energy hog?" When we boondock, propane is always abundant -- electricity is usually scarce!

[dave17352]

Is there a propane furnace in the rig.

[Mello_Mike]

pianotuna wrote:
Cover the cans with a black tarp. Double up on the covering at night. Pack the cans tightly so they touch each other.

x2

[pianotuna]

300 ma @ 12 volts is 3.6 watts That's about 12 btu's. That also assumes 100% of the output of the led is heat (You can buy an infrared one btw).

I don't think that amount of heat is going to do anything for you. On the other hand an 1156 incandescent does 22 watts or about 75 btu's and it does a LOT of heat.

profdant139 wrote:
I would power the LED by tapping into my 12 volt system, with a switch. It would not draw much power -- maybe 300 milliamps. The only trick would be to remember to shut it off in the morning!!