Alde in Sub-Zero Temperatures?

DougH

I love the quiet heat of the Alde, and really appreciate that it doesn't use much propane, and even less electricity when boondocking. And after a night of heavy use, the ice columns from the exhaust vent to the ground are beautiful.  

But for those who camp at 10F or 0F or below, how warm can you keep the camper? I don't have my air conditioner vent covered, so even with all the windows and ceiling vent closed I still get enough air exchange with the outside to keep condensation to a minimum (bathroom mirror, a little on the windows). My question is that I'm only getting maybe 30-40F degrees warming above ambient at much colder temperatures.

At 20-30F outside, I can hit 65-70F inside pretty easily on just propane.  But once it hits 0F, I'm lucky to keep the inside above freezing.  Which is an issue for my camping trip water canisters. Kind of hard to boondock in the mountains with no water except reheated snow. I have a warm sleeping bag, but I need to keep the interior above 32F at night, and would rather not add an extra Mr. Buddy heater to do so. I just had to cut short a trip since with this weekend's polar vortex I'd be at -10F to -20F for several nights on the way back to Texas (which is also seeing subzero temperatures this coming week).

I guess I could try adding an exterior sealing air conditioner cover, then crack a side window to see if I get a little warmer, without condensation running amuck. And I could replace the Alde fluid again, but it looks and tests fine on pH and on the refractometer.

I realize this isn't a 40,000 BTU heater, nor is the T@B a 4 season camper.  That said, on propane only, what differential are other winter campers in T@B land seeing between outside and inside temperatures when it's 10F or below outside?

4ncar

How large is your water container?  Even a 1 gallon jug would take sometime(days) to freeze solid at 32 degrees.  that said, if you are keeping the inside temp at 32 degrees(air night) & above(during the day) your water should be fine.  FWIW: BITD when I was winter backpacking in sub zero weather, the Nalgene bottle had to be inside the sleeping bag at night and under my parka during the day.. had to!!

ScottG

Heating is as much about loss as it is input, and the greater the temperature differential the greater the loss.

The T@B is a leaky, lightly insulated shell with a high surface-area-to-volume ratio. At some point, that little boiler and two short convectors are just not going to keep up (something you likely already know given your last comment). It's relatively simple physics--dedicated number crunchers could probably do a passable heat-loss calculation to see if mitigation efforts would even make a dent at those temperatures.

Even in houses, infiltration (leaking) is usually the biggest contributor to heat loss, so plugging those gaps as you suggested should help some. Adding insulation to reduce conductive heat loss would be a bigger challenge.

I realize this doesn't really answer your specific question. I've camped as low as 30F and the Alde (which cycled frequently) easily kept the camper at a toasty (at least to me) 60F. Below those temps I'll trade camping for a more seasonal pursuit.  ;-) 

DougH

@4ncar Yes, I'd rather not sleep with my water... two 4 gallon containers and one 5 gallon filtering jerry can that doubles as my cold shower rig in the winter. There wouldn't be much room in the bag left for me. 

I need that much water for a 10 day trip without hookups... with mandatory hot coffee in the mornings. Typically also carry 5 gallons of pink stuff to mix into the gray and black tanks until I can dump at the end of the trip.

Solar wise, I only need 100Wh a day to keep the 12V systems on for lights, the fridge, and charging phones (fridge doesn't use much when camper runs between 35 and 50F each day), and I always get the Victron back to float by noon even with cloudy skies. So if I've had a good 500+Wh winter sun day, that also gives me a couple hours of the baby Honeywell space heater time. Enough to spoil me with a warmed up bathroom before a shower.

But my next & larger camper I suspect will need a mini wood stove for enjoying winter in the mountains. I just saw Slim Potatohead is putting his pellet stove back into his new-to-him eggshell camper.

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@ScottG Those convectors are working as hard as they can, and the back wall is nice and toasty (I sleep sideways on the back of the bench) as is the side bench area. But yup, I only need to double that output at zero out. The best back country powder requires sacrifice I guess.

Dalehelman

The Alde just can’t keep up when the temps hit the low teens and below. I find supplemental heat is required to be comfortable. You just have to find out what type works best for you. I use a mister heater buddy. We need to open the windows a little to help reduce condensation. The buddy heater can more than compensate for that. It can be more of an issue in severe wind conditions.

DougH

@Dalehelman Thanks! I have the small and medium sized Mr. Buddy(s) at home, but never tried them in the T@B since I was worried about condensation.

https://youtu.be/XLX3ZR2AoLs

Very good to know that even with the windows cracked for humidity control, an aux propane heater can keep the camper warm. Exactly what I wanted to know.

Dalehelman

@DougH. It also is important not to bring in moisture from the outside like wet clothes and shoes. Most cooking and obviously no showers.

DougH

Okay on the cooking, but no showers? For a week of sweaty skiing / snowshoeing?  Smelly!  

I'm hoping if the shower is cold, and I don't get a towel wet afterwards, that's not the biggest humidity generator, versus 300mL from just breathing or the liter from the Mr. Buddy.

4ncar

@DougH: I am surly not suggesting to put your water into your sleeping bag, just sharing an experience. What I am saying is at 32* and the large containers of water you state you have, you shouldn’t worry that they will freeze.

Verna

@DougH, I bought two 100 oz collapsible water containers with wide lids (maybe Platypus brand?). I have heated water in a tea kettle on the stove, mixed hot and cold in each bag, closed them and stepped in the shower with a silicone wine glass (it’s what I had on hand). I poured a glass full of water over my head and wetted down. Soaped up. Then used two or three glass fulls to rinse off. Refreshing and cleaning shower, not much humidity, and not much water in the gray tank. I put antifreeze in the gray tank after the shower. If I didn’t use all the water, I kept it for the next day. 

During this time, I also used Double Doodie bags (or double trash bags with kitty litter) in the toilet instead of flushing liquids into the black tank.  It worked for the cold 5 days quick cross country trip to AZ from home. 

DougH

@Verna Sounds like a good solution. Daily showers just make folks better prepared to meet the day.

Some time ago I bought a LifeSaver 5 gallon jerry can that filters water. Has a manual pressurizing pump, but also a shower attachment. Place it on the T@B sink, run the shower hose into the wet bath, and Bob's your uncle. Enough water with 15 pumps to do the same wet / soap / rinse a time or two when the T@B is winterized. And the gray tank is reasonably sized for short showers, even if the black tank's a bit small for longer boondocks or full-timing.

I understand that the BLM and NFS 14 day limits were created because that's the time it usually takes before a solo T@B full-timer needs to dump their tanks. Still holding out hope for a next gen T@B that's bigger than the 400, yet T@DA shaped, with fully enclosed larger tanks and valves, and thicker walls for hot summers and -10F winters though.

WY320Camper

I just got back from camping overnight at about 8500ft with temps just below zero, not sure as I didn't check the truck temp reading when getting up in the am. The inside was somewhere close to low 60s. My issue was the 12v battery lost too much power to run only on battery and had to run generator for 6 hours in the night. Slept warm though.

DougH

@WY320Camper : Wow, was that just the Alde or did you supplement with a small propane catalytic heater? 0F up to 60F on a 320 Alde alone is fantastic.  Very little wind?

WY320Camper

No or little wind, large snow pile West of camper, just Alde on propane with generator keeping battery charged. I have the 2020 camper, solar package without any modifications. The door to the bath was closed with ski boots set next to the head and had to pull liners out in am to put under truck floor heater! Will be investigating the mods to enclose tanks and insulate/heat battery to allow use of water while skiing. 

DougH

@WY320Camper Thanks, makes sense. There's a dozen or so winter camping skiers on the forum who have done Alde or 12V heating for fresh and gray tanks. I tend to blow out the lines before I leave the ski area so they don't freeze on the highway as I head to the closest dump. But if it's 15F or below, I stay fully winterized the whole time.

dragonsdofly

@DougH, while stranded in Evanston, WY, November of 2018 (vehicle troubles), we (DH and me) were plugged into 30 amp power and running the Alde on 2 kw setting. We did not supplement with propane and were able to keep our 320 S in the 55-58 degree temp range when ambient temps were -10/-12°F. We did use a coroplast cover fashioned during our emergency duct taped over the a/c opening. We have the model t@b with a vent hole through the floor under the fridge and we did not cover that. The floor was very cold. We ran the fridge (3 way) only a few hrs a day on electricity. It was so cold we really did not need to run it much, less than 24 hrs during our 16 day stranding. We were at approx 7,000 ft altitude. Needless to say, we survived our challenge. We took only "sponge" baths and used baby wipes to clean up. At those temps, any water in the tanks is gonna freeze. My DH was emptying the black tank twice daily and though we were mixing our "liquid deposits" with equal parts rv antifreeze, the black tank contents would get very slushy in a matter of hours. I will not say we were toasty warm, but certainly not in any danger of freezing to death. Had we decided to supplement our Alde electric heat with propane, we might have been a bit warmer, but we decided to save our propane for the mad cross country dash home. 

DougH

@dragonsdofly I vividly remember being at the edge of my seat reading about your excitement at the time. May your travels never be that adventurous ever again. 

I've got another trip into the mountains planned soon... I'll borrow your A/C cover idea and see how much difference it makes just on propane alone.