Mini-catalytic heater for keeping tanks warm off-grid??

[profdant139]

I really want to enclose my underbelly and do more cold weather camping. But unless I have a huge solar array (impossible on such a small trailer), I can't power the heat tapes to keep the tanks from freezing. And ducts from the furnace are out of the question for the same reason -- that needs too much juice.

Nor is running the generator all night an option -- I boondock for the peace and quiet, not to listen to my Honda purring away.

There has to be a way to rig up something like one of those mini catalytic heaters inside the enclosed underbelly, just to keep things above freezing. Propane is cheap and abundant and easy to transport.

I don't care how cold we get inside the trailer -- we dress like Eskimos and sleep under down comforters. But frozen pipes and tanks are a deal killer.

I know we could keep plastic jerry cans of water inside the trailer, but that is an inelegant solution, especially in such a small trailer.

So that is my question -- has anyone seen a radiant heat solution to the cold underbelly problem?

Thanks in advance for your creative suggestions!

[profdant139]

rj, that would work, except that the furnace draws a lot of juice. We mostly boondock. If we had hookups, it would be a different story.

[rjsurfer]

If you dont mind running the rv's furness, how about drilling some 1" holes in the metal ducts (facing down into underbelly) under the floor grill?

A decent portion of the heat should get into the underbelly.

If it doesnt work out just put a piece of the silver duct tape over the holes, no harm no foul.


Ron W.

[SteveAE]

profdant139 wrote:
there is no way I can fit into the freezer to watch what's going on. 😉

Dan,
Sounds like a perfect excuse to get a new, walk-in, freezer;)
Let me know how that plays and, if it works for you, maybe I'll give it a try...

[profdant139]

Steve, that is a good idea, except that there is no way I can fit into the freezer to watch what's going on. 😉

[SteveAE]

profdant139 wrote:
It's tough to simulate freezing conditions in order to test this idea -- it gets down to the high 50s at night where I live!

Simple. Get a piece of pipe about the same size as you want to protect, fill it with water and put it in your freezer. Measure the time to freeze. Now thaw, and put your LED bulbs on it and repeat (don't worry, the LED bulb won't generate enough heat to cause your freezer to work any harder)

[SteveAE]

Watts is watts. It doesn't matter if it comes from a light bulb (of any type), a furnace, a campfire.....or even just rubbing your hands together.
Without calculating your actual heat loss, it's impossible to say, but my guess is that you will need a minimum of a couple hundred watts to even start to be worthwhile doing. That's a whole lot of LED lights and the power usage will be the same as if you used a heat lamp or heat pad of the same total wattage. Watts is watts. If you only want a small amount of heat, then much better (easier and cheaper too) to simply conserve the heat in the water by insulating your pipes and tank.

Haven't seen highs in the low 50's for quite awhile here. Enjoy the warmth.

On edit.
The couple hundred watts I "guessed" at earlier would be to keep your whole basement area above freezing in, maybe, temps down to about zero (maybe?) assuming your basement area was covered and the air was fairly still (not windy). Uncovered and it would be impossible with that small amount of power.
If, on the other hand, you just want to keep a pipe, valve or even your tank above freezing, then it would take much less power....maybe 10 to 50 watts.....maybe....depending on how big the surface was and how it was insulated. Way more than a few LED's will give you, but possible if you use an appropriate heat source (you want something that contacts the surface to be protected....but doesn't get so hot that it melts the plastic).

I still suggest that you cover the bottom of your trailer, and heat and circulate the water in your tank and lines with your existing hot water heater and water pump. Way more possible than trying to generate this power with your limited battery power....and you already have everything you need in your trailer.

[profdant139]

I have some old incandescent bulbs, and they do give off more heat than the LEDs. But they also use more power. So that is why I am thinking of an LED plastered up against the vulnerable part of the outflow tube.

It's tough to simulate freezing conditions in order to test this idea -- it gets down to the high 50s at night where I live!

[pianotuna]

Hi profdant139,

The venerable 1156 bulb is 2 amps--so the most you would get is 24 watts of heat. Not enough.

profdant139 wrote:
DW suggests a 12 volt LED bulb, like the ones in the inside fixtures. (The bulbs emit some heat and use almost no wattage.) This would be inside an enclosed space, right next to the outlet tube coming out of the fresh water tank, and we would turn it on and off manually. I would monitor the tank temp to see how much this affected the water. Might not be enough warmth. But all I want is minimal effectiveness, not hot water!

[LenSatic]

When I replaced most of our interior lights with LEDs, I kept 2 incandescent ones, that we rarely used, to provide heat if needed. How about a couple of those?

[profdant139]

DW suggests a 12 volt LED bulb, like the ones in the inside fixtures. (The bulbs emit some heat and use almost no wattage.) This would be inside an enclosed space, right next to the outlet tube coming out of the fresh water tank, and we would turn it on and off manually. I would monitor the tank temp to see how much this affected the water. Might not be enough warmth. But all I want is minimal effectiveness, not hot water!

[pianotuna]

Hi RinconVTR,

My waste tanks and valves are enclosed...I added a 120 volt outlet to them. I use a mechanical thermostat to control the heater.

I agree, it would be useless in an open underbelly.

RinconVTR wrote:

Got it. I know of those tiny little "personal heaters" and I never would have guessed anyone was using those for an anti-freeze device.

We've had a few people try them at work (indoors...heated office) and they were a joke.

Please dont take offense, but I cannot believe you've found them effective within the unsealed underbelly of an RV to prevent freeze ups. The air temp rise math doesn't work at all, and if you add any air movement from the outside, its simply impossible.

There has to be more to this story.

[RinconVTR]

pianotuna wrote:
RinconVTR.

I happen to use a 200 watt heater for my waste tanks. That's a little less than 700 btu's. The conversion number is 3.41 btu's per watt.
.

Got it. I know of those tiny little "personal heaters" and I never would have guessed anyone was using those for an anti-freeze device.

We've had a few people try them at work (indoors...heated office) and they were a joke.

Please dont take offense, but I cannot believe you've found them effective within the unsealed underbelly of an RV to prevent freeze ups. The air temp rise math doesn't work at all, and if you add any air movement from the outside, its simply impossible.

There has to be more to this story.

[pianotuna]

Hi GordonThree,

Nope I meant 700 btu's. In the worst of the winter I do move to a 600 watt heater--but for that to run all day long is hard on the battery bank--even when I have the thermostat set to 4 c (39 f).

GordonThree wrote:
Hopefully he meant 700 wat max?

[GordonThree]

Hopefully he meant 700 wat max?