Propane heat

[rfrance0718]

I've seen heaters on boats, but don't know much about them, except that they have flues and seem to have some fire resistant wall treatment around them  I have a propane heater in my little camper, and the fridge runs on propane as well. The little catalytic heater is 3000 btu and has no exhaust or fan. I run a little 12 volt fan that blows some air past the heater towards the floor and seems to distribute the heat perfectly. I saw some posts about my heater, the Wave 3000, not being a good choice for small campers because of excessive condensation, risk of Carbon Monoxide, and having to vent so much to avoid carbon monoxide that it wouldn't provide adequate heat. I just went off grid for 3 days in single digit temps and am pleased that none of those issues seem to be a problem.

Carbon monoxide: I have a Kidde CO monitor that has a digital display and reads low amounts of the gas. I also have a gas detector to sniff out propane leaks. The carbon monoxide detector is mounted head high and the gas detector is by the floor. For a test I have run the heater for several hours with my roof vent shut and the detector didn't register a thing. In day to day use I open it about an inch, so about 10 square inches. During the night I can feel that I'm breathing some of the fresh air coming through the vent , which is reassuring.

Heating ability: I just ran the heater 2 nights in 0 degree weather. I ran it on low, had my vent cracked, and monitored the detector, which stayed on 000. I was perfectly warm with a light blanket, and I felt fine.

Moisture: Since I had read about moisture issues I built the camper to breath as much as possible. From inside out my ceiling is a layer of fabric hull liner, a 1/2 inch of foam, 1 1/2 inches of pink insulations, a 1/4 in. of plywood, layer of 8 oz glass, and paint. I do get condensation on my windows, but it's not excessive, and drips out of the weep holes. I don't sense moisture anywhere else.

I'm feeling pretty sure that the poster was off base. He said that he got CO readings when he tested his heater, which could mean that he had a unit with combustion problems. I found issue with his other claims as well, so I'm feeling good about my choice.

I also have solved another issue. I have a 20 lb tank mounted on the camper but I don't have a practical way to keep a spare. I had heard that you can monitor propane level by weight and have found that to be very true. For a test I used a partially full tank and ran the heater and the fridge for 8 hours. The empty tank weighs 17 pounds and this one was at 22.5 when I started. After the 8 hours My weight was down to 21.3, meaning that I had used 1.2 pounds. That would be 3.6 lbs a day, which would allow me to run it for about 6 days. I started my trip, with the tank full, and weighing 36.8 lbs. After I ran the heater and fridge for 48 straight hours on my trip I found that I had used 7.5 lbs. I can live with that. I also bought an adapter that allows me to run the system on one lb. bottles. With a couple of these as backups I feel that I can run the tank right down to E. with confidence. Hurray!

My trip was a lot of fun. They had about 15 inches of snow on the ground, and the cold temps make for really good skiing. The Cross country ski center in Roscommon let me just stay in their parking lot. I skied on their groomed trails some and did some back country skiing as well.

All good

[Krusen]

Your fridge may have an outside vent?

Your propane catalytic heater will not be inclined to produce carbon mon oxide, but it does consume the oxygen in the air.  This can kill just as surely as monoxide poisoning.

Many years ago, I had a slide in pickup camper with cabover bunk.  It was home built, and very tight.  First cold overnight, snowed all night.  I lit a candle, and placed it on the gas stove, in the fry pan.  No pilot light for the stove.  I hoped that the candle would give just enough heat to stay comfortable in my good sleeping bag.

 At some undocumented hour of the night, I woke in the cabover, with a headache.  I rolled over to look around, and found that the candle was about to go out, with a very orange flame.  It had inadequate oxygen, having used much of what was in the camper for its flame.

I rolled carefully out of bed, and barefoot, wearing just underwear, opened the door, and stood on the snowy cold steel tailgate, while nice warm air flowed past my head, and frigid air flowed in, past my feet.  The candle flame turned light yellow, and full size, there was now plenty of oxygen.

When the airflow ended, I closed the door, wiped my feet on the dry rug on the floor, put out the candle, and returned to bed.  Once there, I slightly cracked the vent by my head, pulled the edges of the sleeping bag tight around my head, and slept safely to the morning.

A carbon monoxide detector might have saved me from lack of oxygen, since I did not have a catalyst keeping the flame clean, but the gradual decrease of oxygen would have done me in.

Your slightly open vent is essential, never leave it closed, no matter how cold it is.  Secondary bonus, the moist air rises, and is the first to vent out, helping to keep the condensation under control.

Happy camping.

[rfrance0718]

Thanks for the input. I would think that my heater would use a bit more oxygen than your candle. I was thinking about oxygen levels during my trip as well, and wondering if a blood oxygenation monitor  would indicate that there was some change, even if it wasn't enough to produce headache, etc. Just a thought. I also use a small space heater if 30 amp supply is available. I have gone the night with it running and the vent closed. The heater would use little or no oxygen, but I would certainly spend some of it. I haven't felt any ill effects. I figure that my camper is about 1600 cubic feet, and it's pretty tight as well. I wonder how much we use just breathing?

[rfrance0718]

I found the following. It sounds like I could go about 2 days without letting any air in, and I've never gone more than 8 hours. Combustion, even little flames, must use a lot more oxygen than we do. None the less, probably a good idea to crack the vent a bit.

Let's say that the room is 30 feet by 20 feet by 8 feet, or 4800 cubic feet. I believe that high carbon dioxide levels will kill you before low oxygen levels will. Inhaled carbon dioxide is 0.04% by volume, exhaled is a bit over 4%. Inhaled oxygen is 21%, exhaled 15%, a difference of 6%. A person breathes about 6 liters per minute, or roughly 9000 liters/day or roughly 300 cubic feet/day. Thus that person will decrease room oxygen by 300 x 6% = 18 cubic feet/day. He will increase room carbon dioxide by 300 x 4% = 12 cubic feet/day. Comfortable carbon dioxide levels are less than 1000 ppm (parts per million) (0.1% of room air). Dangerous levels are above 10,000 ppm, especially above 30,000 ppm. Let's take 30,000 ppm (3% of room air) as our death point, although obviously that's arbitrary. 0.03 times 4800 = 144 cubic feet of carbon dioxide in the room would be deadly. 144 / 12 (cubic feet of CO2 exhaled per day) = 12 days to death in that sealed room. Originally there were 4800 (room cu ft) * 0.21 = 1000 cu ft of oxygen (rounded) After 12 days, 18 (cu ft/day of oxygen decrease) x 12 = 216 cubic feet oxygen lost. That leaves 784 cubic feet of oxygen in the room, or 784/4800 = a little over 16% oxygen in the air. While people will have symptoms at 15% or less, it would be rare to die with oxygen levels above 10%. So my conclusion is that in the above scenario, a person would die in around 12 days, and from carbon dioxide toxicity rather than oxygen deprivation. Are my calculations correct on this? Thanks.

Reference: https://www.physicsforums.com/threads/how-long-can-one-live-in-a-sealed-room.685796/

[rfrance0718]

oops, I have about 200 cubic feet. So maybe my air is getting thin after just 12 hours? Once gain, probably worth cracking the vent.

[Grith]

Whilst many have used gas stoves, gas fridges and even gas heaters as discussed here I personally don't like gas on boats with nowhere for heavier than air leaked gas to escape.
Apart from the oxygen consumption, carbon dioxide production and moisture addition of burning gas the further risk of leakage due to the constant motion of boating creating a failure point in some fitting or hose is very real.
Many will disagree and each to their own but I prefer electricity and use a combination of a 12v throw rug/mattress warmer and occasionally a brief burst of electric fan heater to bring the inside temperature up quickly.
I still have a small amount of ventilation cracked open as the reported low oxygen situation from a candle above could have actually been caused by just breathing extracting the oxygen in addition to the candle.

[Norm L.]

I think most all of us would agree that electricity is best for most things, but is not available on small boats unless sleeping on land during a trip.

I remember a thread long ago on the candle under a terra cotta flowerpot. The pot creating radiant warmth.
In our current freeze I had a desk lamp with 100 watt bulb under the tent I constructed over the orange tree with bamboo and sheets. The bulb gives off heat but so did the lamps heavy glass shade.

[rfrance0718]

I camped next to a young guy at Thistle Nationals last year with an interesting setup. He had a Sprinter Van with 800 wats worth of solar panels and a matching bank of lithium batteries. He can go off grid and run heat or AC along with his refrigeration on an ongoing basis. I have 100 watt panel and one lead acid deep cycle battery. My setup won't run my fridge, much less heat. I don't know how much difference the Lithium batteries make.

[Noemi - Ensenada 20]

When I camp in a van at the Wheatland music festival, I usually put one sleeping bag under me and my sweetheart, and another over us.  If it's really cold, I include a wool blanket underneath as well, and several over.  Said sweetheart used to complain about all the stuff I pack for just a weekend, but after realizing he can sleep in comfort because of it, he stopped.

[pgandw]

The LiFePO batteries can sustain higher loads better than a LA deep cycle (a 100AH battery can power a 50amp load for over an hour), can recharge 3-4 times faster if the charging current/voltage is available, and weigh 25% of the equivalent LA deep cycle capacity.  LiFePO batteries actually prefer being kept in the 25%-70% state of charge, whereas LA batteries do better when kept close to 100%. 

LiFePO batteries have come down substantially in price - 100AH 12 volt (reasonable quality) is now less than $300 - but there are a bunch of poor quality batteries too in the lower price range.  2 GC-2 6V golf cart LA batteries (comparable capacity) cost $200+ at Costco or Sams Club.  LiFePO batteries cannot be charged when temps drop below freezing (32def F) - a critical issue in much of the US as the past week has shown.  Temp is not an issue for LA batteries.  But the LiFePO battery can be used for loads down to about 0deg F.

Because the price has come down so much, when my LA GC-2s die on my camper, I will shift to LiFePO.  Similarly when I install an electric system on my Mariner, I will use LiFePO.  Only Will Prowse (internet Lithium battery reviewer) recommended brand will be bought.  But I live in Eastern North Carolina where 0deg is unknown, and below freezing is 3-4 days max maybe 4 times a year.

My approach to LiFePO battery maintenance is different.  When I get home, I do not recharge a LiFePO battery since they like to be stored at less than 100%.  I plug in the charger the night before a planned use and recharge to 100%.

Fred W
Stuart Mariner 19 #4133  Sweet P
Yeopim Creek, Albemarle Sound, NC

[rfrance0718]

LifePO batteries are new to me. From the different literature, and from your writing, I'm trying to figure out how they would change my day to day use. In my camper my solar panel easily tops of my LA battery during the day. Then I can run lights, charge stuff, run my lap top off of my inverter, and run the fridge for a short time.

In the boat it is pretty much the same, although I don't have a fridge. The big difference is that the GPS is a power hog and I've learned to use it sparingly. Aqua Maps on my phone shows me everything that the GPS does anyhoo.

It would be cool, so to speak, if I could get enough juice to run the fridge thru the night. I've also thought about one of those 12 v coolers for the boat.

[Norm L.]

I just finished a blog on modern battery science. It is from the viewpoint of commercial use and how different the battery needs are among personal and commercial EV's and how the needs vary as you go up in size as in grid distribution, rural windfarm storage. all pretty steady on power in and power out.
On board ships, where it is just starting the draw is constantly changing. At sea in nice weather it is steady draw. But in a storm with the propellor in and out of the water, it takes an amazing control system. Then with radars x-band and s-band need different inputs at different pulses.

I learned a lot about all the different types of batteries coming along, and when picking one for 2 characteristic you need, say high power and long life you may end up giving up charging times and affordability. No sizes fits all.