Using water heater to heat camper shell?

Joellivin

New member
OK... Not sure if this is the right place to post but... I have a 2019 f150 with 6.5 ft bed.
Trying to get a camper shell setup for adventures with me and my two teanage boys and will need some sort of Safe heat source.
I don't feel comfortable with a sort of big buddy system (there will barely be enough space for all us much less clearances needed for a propane heater).
I was also thinking, hot water would be really nice to have, there's nothing like a good shower after summiting a mountain or a day snowboarding.

Why not combine the 2?
Would it be possible to do a radiant floor system with an on demand rv water heater and a 12 volt pump?
Such a small area to heat it shouldnt need to constantly circulate the water.
I'd imagine that it may be slightly less efficient than a direct air heater... But I don't want to have 2 gas appliances to deal with where I can just have one.

Here's how I envision it, please comment any holes you see in my theary.
I'd want it to be removable so, you have a durable piece of plywood with small pex attached to it back and forth back and forth then another piece of plywood on top with spacers in between.
So when it's time to go camping you put the "floor" in (include some insulation on it as well) then plug its lines into the water heater (set up in some sort of other modular plywood setup or outdoor unit maybe) and kick on the pump.

You could tie in a water tank on the 'cool' side of the lines to add more water to the system, you could create a split and have it going to the shower right outside as well.

One issue I see is that you'd have to set the 12v pump on a thermostat and also leave the whole system on even if you aren't around the vehicle, the last thing you'd want is for any of it to freeze and crack. You could of course bypass this by using glycol or something but then you lose the hot shower ability.
You could set the thermostat very low so it only heats up a bit of water every 30 min or so to keep the whole thing from freezing.


So that's my main question. If you care to read on I'll describe what my overall and eventual plans are.
I want to pick up a camper shell, set it up with modular removable camping solutions based on where we are going, who all is going and what the temps will be.
One of those modules would be the heated floor listed above.
We could set it up with a bed on each side and middle isle (if it's just me and one son or me and both sons).
There would be a drawer for kitchen stuff, a large drawer for clothes that we could leave out to leave room for snowboards ect.
The goal being to be as versatile as possible.
Then, when I have the time and money I want to build something scimilar to the four wheel camper project M.
This things looks awesome but I don't think I can afford it. I'd use the pieces of the camper shell to help with some. Like the back door, the side and front windows could all be put in.
Then the modules I made for the shell could also be used for the pop up camper but we could fit much easier in there.
I saw a guy with one of these bare pop up camper shell looking things driving around and wasnt able to chase him down to ask about his rig. But it doesn't look too insane to make.
So imagine project M with radiant heating, removable "kitchen" and furniture so I could use the truck as... Well a truck, a shower on the outside, radiant heater throughout.
May be a bit of a pipe dream.

Thanks for reading
-Joel
 

phsycle

Adventurer
How cold we talking?
Typically, good pad with a nice sleeping bag would be best. Keep it simple.

That said, 3 adults in the pick up bed......wouldn’t work for me.
 

Joellivin

New member
We are talking very cold, ski trips, base of mountains ready to summit a 14er, Colorado and Wyoming winters.
Yeah it will be tight. We measured it out and laid it out on a rug to see and it's doable until I get the pop up version built I want to eventually.
But comfort is key, not just thick bag and be absolutely miserable in a snow storm but I want the kidos to want to go out again.
How cold we talking?
Typically, good pad with a nice sleeping bag would be best. Keep it simple.

That said, 3 adults in the pick up bed......wouldn’t work for me.
 

Joellivin

New member
Its interesting idea. Like Eccotemp L5 and circulating pump.
I think it will be sloppy in regards to BTU of fuel to BTU released into habitat.
But would be inexpensive enough to build a mock-up to work out any bugs.
One caution.
If its a closed heating loop, be sure it has some kind of overpressure vent. Better yet, just dont use closed loop.
Use a vented accumulator tank or similar.
That sounds like solid advice. I didny really think of it being a closed loop and the inevitable rise of pressure. Do the on demand water heaters have any sort of on board safety pressure releases?

Yeah it probably won't be the most efficient with propane, but as long as a 5 gallon would last me more than a weekend then I'd call it OK. Being such a small space and as close as we'd be sleeping to the hot water lines it probably won't have to work too hard to keep it up to temps.
I will definitely check out those things you mentioned though. And as soon as I grab my camper shell I'll do a mock up to see how it does.
 

plumber mike

Adventurer
Yeah I'd thought of that. But the engine would need to be running for it to work and I don't want to have it idling all night while we sleep.
The engine could make the heat during the day or when it last ran....if you could insulate and store some for use in the overnight, The standby losses on some of the more efficient traditional water heaters are impressive. Calculating volume requirements could be tricky. Whatever heat remained could be sent back to the coolant side to reduce ice cold startup on the truck.

I toy with the idea of a very small wood fired “boiler” that could be set up on quick connections to the pex next to the truck. A twig fire could boost a hot shower without running the truck, or again preheat the coolant for a cold start.

Good luck with your endeavor.
 

Martyn

Supporting Sponsor, Overland Certified OC0018
You could run a dual system, hot water on one side for showers etc , then a heat exchanger to heat the glycol for the radiant heat system. I think Espar makes a nice small exchanger.
 

Alloy

Well-known member
First thing I do is find out the min output water temp of the heater. Over 90F will be uncomfortable to walk/sit on.
 
D

Deleted member 9101

Guest
With what power source? He doesn't want to run the truck all night. Anything that produces heat will kill a battery very quickly especially in sub freezing temps.
A 12v mattress pad doesn't draw much power at all. A spare battery could power it all night with out any drama, or water.
 

Joellivin

New member
First thing I do is find out the min output water temp of the heater. Over 90F will be uncomfortable to walk/sit on.

true, I wonder if its all the way at the floor if I have a bed platform in between if it wouldn't be too hot, then on the floor portion a plywood piece as well as some carpet in between. Will definitely be something to watch. The pump I would see if I could set on a thermostat, so basically the water only refreshes with hot water once the ambient temp reaches a certain level.


A 12v mattress pad doesn't draw much power at all. A spare battery could power it all night with out any drama, or water.

A heated mattress pad may be nice, the problem is I'd need 3 running, I will look into power draws from them but I'd imagine running 3 may take more power than I want to deal with.
 
D

Deleted member 9101

Guest
A heated mattress pad may be nice, the problem is I'd need 3 running, I will look into power draws from them but I'd imagine running 3 may take more power than I want to deal with.

Actually you would only need two, max. Your truck bed isn't wide enough for three. You can get one that's queen sized that would be the size of your entire truck bed.
 

luthj

Engineer In Residence
Depends on the temps, I find about 20-60W is enough for 2 people in a bed. Bit less for one. Not crazy power levels, but significant.

Hydronic heating loops that do both water and air are common on boats and larger expedition rigs. Get a chinese diesel coolant heater, a heater core/fan, and a plate heat exchanger.

Its hard to beat one of the 200$ chinese made diesel air heaters for compactness and cost.
 

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