Connecting Generator to Trailer - R-pod Owners Forum (2024)

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The boiling point of a liquid is not a fixed number, it depends on the vapor pressure above the liquid. When its stated that the boiling point of propane is -44F that means it boils at -44 at standard atmospheric pressure (15psi). Since a low pressure regulator only delivers gas at about 0.5 lbs above atmospheric pressure a propane cylinder shouldn't have any problem delivering enough propane to light an appliance at 20F. If it does I'd suspect that the problem is the regulator and gas delivery line is undersized for the btu capacity of the appliance. That drives the pressure required from the cylinder higher to compensate for the regulator and hose losses, which in turn requires a higher propane liquid temperature to produce.

The other problem as StephenH says will be keeping the furnace lit as you boil off propane and the cylinder liquid temperature drops due to boiling off the propane. It takes about 700 btu to vaporize 1 gallon of propane and our 20000 btu/hr furnaces will burn about a gallon every 4-5 hours so they will need about 150 btu/hr of heat delivered to the cylinder to maintain its temperature. That's not a lot but some way of transferring heat to the propane is required. This is where a larger tank helps because its larger surface area absorbs more heat from the environment than a smaller one. Placing the cylinder in a warm location will also help, or just placing it in a water bath.

We run a lot of stuff on propane at home. The stove, oven, two water heaters, three furnaces, and a gas clothes dryer. We don't get ridiculously cold temperatures, although we've had temps below 20F for a week a couple of times. There has never been a pressure problem.

My parents heated their home and hot water with propane in Minnesota. That system worked fine down to -55F at least once that I know of, and it has worked at -30F and -40F almost every winter.

So there is a lot more to it than just OAT. In our (and our parent's) homes, the propane line runs underground for some distance. In our case, it's about 140' underground, and in our parent's case it's at least 100'. So I think the relatively "warm" underground temperature allows the propane to revert to gaseous state before its used by the various appliances.

I speak from experience. We were in our RPod when the temperature was about 4F with a strong wind chill. Yes, we were going through a lot of propane. Yes, we did have a propane hose problem that limited the propane flow so that when the furnace was running, the stove would almost go out. Replacing the regulator didn't help. When I replaced the hose, it did. However, it was still a challenge to supply sufficient propane in those low temperatures.

How big a tank is supplying your wife's studio? A 100 gallon tank will be able to generate more pressure than a 20 gallon tank in the same conditions.

StephenH
Happy is the man that findeth wisdom,...

ouR escaPOD mods
Former RPod 179
Current Cherokee Grey Wolf 24 JS

You keep it in the back of your truck and get your wife to lift it. After all it's not much heavier than a bag of portland cement.

We heat my wife's studio with propane and the tank is outside in the cold. We've had no trouble lighting the heater even when the temps are down in the single digits. StephenH, how can you say that there isn't phlogiston in propane?

Quite frankly, if it's too cold for the propane tank to supply gas, it's not likely that one would be out camping in a marginally insulated rPod. You'd be going through a tank of LP every day or two just to keep warm.

It depends what you're running on the generator. The inverter section reduces noise and fuel consumption by reducing engine rpm at low power levels. Reverts to full rpm at high loads. At high loading which only occurs when running the a/c or the microwave the Honda isn't much quieter than a standard generator, if any. I mostly use my genny in the summer for a/c operation so noise can be a significant issue.

This is a handy chart to compare the relative amounts of energy per unit of various fuels.

Phlogiston has nothing to do with it. BTUs per gallon does. LP does burn cleaner than gasoline, only because it is a single type of molecule instead of the blend of molecules that is gasoline, some of which burn cleaner than others. The down side is that it takes more gallons of LP to get the same energy output.

Here is one example I found of the relative power output of a generator on gasoline vs. propane:

Edit: I found a chart for a Champion dual-fuel inverter generator. The comparison is:

Gasoline: 3400 starting and 3100 running watts

Propane: 3060 starting and 2790 running watts

Also, most of the sources I saw stated that in temperatures below 20F, the propane was not viable unless there were a method of warming the tank. Even below 40F, the pressure in the tank starts to drop and may become too low to start the generator on LP alone. Even though the boiling point of LP is -44F, as the LP is used out of the tank, it cools the tank to below ambient temperatures. It isn't unusual to see frost build-up on the tank when LP gas is used at a high rate. With ambient temperatures in the teens or single-digits, it may not be possible to maintain sufficient gas flow to run the generator, especially if the same tank is being used to supply the furnace. A separate tank would be better, especially since it could be placed in the area where the cooling air for the generator is exhausted which would warm the tank. However, it would be prudent to not place it in the exhaust from the muffler so that it does not become overheated and start to vent propane from too much pressure.

StephenH
Happy is the man that findeth wisdom,...

ouR escaPOD mods
Former RPod 179
Current Cherokee Grey Wolf 24 JS

I think rods and stones are a much more accurate form of measurement.