Using water heater to heat camper shell?

[phsycle]

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.

Hope all works out. But if it were me, I'd just go out with a mattress and sleeping bags. No, don't go out when it'll be -10deg. I remember my first scout camp out. It was in the middle of summer and I had a blast. Backpacked in a crappy tent, 12lb sleeping bag, and CANNED chili for dinner. Fortunately, it wasn't a super long hike in. But it got me excited to go again. Even further into the year into winter months. Still love camping.

I don't want to be the one to squash the idea. I just think it'll be something you'll use once and it either breaks or no one cares to use it again.

 

[Martinjmpr]

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.

Well, certainly running a couple of 12v batteries would be less complicated than some Rube Goldberg water heater contraption. As long as you had a way to charge them that is probably a simpler way to go. If you had good sleeping bags rated for -10 or so you'd probably just turn it on a half hour or so before you went to bed to warm up the sleeping compartment, and then once you get snuggled in, turn it off. In the morning, do the same to warm up the interior of the topper.

Of course, having said all that, I think trying to put 3 people side-by-side in the bed of a pickup - even a full sized one - is going to be much more of a comfort issue than temperature.

 

[spectre6000]

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.

Hear me out... I don't mean use a block heater in the usual way...

https://www.napaonline.com/en/p/KAT12010?cid=paidsearch_shopping_dcoe_google&gclid=Cj0KCQiAsbrxBRDpARIsAAnnz_PJs9c5866idaY6gi4XjfCcxMvubjJRGxuSO9oOEQ2gzCqHpGoBsbgaAquDEALw_wcB

This is an 850W unit, and you'd run a battery dead PDQ, but if you got a lower power unit (which would likely require a separate pump), add a controller, and maybe ditch the engine heating part, I'll bet you can get a night's worth of heat out of a battery no prob.

If you were REALLY clever, you could use the thermal mass in the engine coolant from when it was running, in a heat exchanger configuration, selective pre-heat water in a tank, and then use that the engine to kick start the whole thing while driving (or a single warm up cycle for being stationary). Then the heater is running on a much lower duty cycle to just maintain the temperature of the system. You're definitely not buying that off the shelf, but if you're halfway savvy with Python (thinking Raspberry Pi), it'd be an easy afternoon's exercise. Pi, thermo-sensor(s) of some sort (I tend to over-instrument, but I'm thinking one for the water and one for the air in the bed, possibly a third for the coolant), servo actuated valves, a bunch of PEX, a tank, some insulation... I've not actually put together a build sheet or anything, but I'll bet you could be fully operational to a high degree in well under $500.

Coolant side:
engine ==== temp sensor ==== valve === heater ==== || heat exchanger interface
...........................................................||==== pump =====||

Potable side:
heat exchanger interface.... tank ||==== temp sensor ======= run through insulated floor ====||
.........................................................|| === pump ==== valve in ==== valve out =================||

Software side:
sensor reading coolant temp to automatically open engine side valve to pre-charge off engine heat
sensor reading water temp to turn heating element on/off
sensor reading air temp to turn recirculating pump on/off
pump to circulate
solenoid actuated valves
Switches for manual operation

Flip switch in advance to pre-heat hot water tank via engine coolant, simply opens valve to engine, then monitors temp to keep water from getting too hot, shuts off if temp gets too high
Once engine is off, continue using coolant to maintain temp until coolant temp falls below water temp set point
Once coolant temp falls below set point, switch to heating element with high/low switch gates
While air temp is low, operate pump on high/low switch gates
Flip switch in the morning in preparation for starting to pump heat back into coolant/engine

I think that's about all the bases... If you really want to get fancy, I've used an iPhone screen on a ready-made plug in board for a very nice touchscreen interface. They're cheap.

 

[billiebob]

Price it all out. But I'd sooner add a propane heater like a Propex unit.

 

[CampStewart]

Price it all out. But I'd sooner add a propane heater like a Propex unit.

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Amen or a diesel powered one. China made diesel ones are cheap and people are doing a lot of creative installations.

 

[Deleted member 9101]

Of course, having said all that, I think trying to put 3 people side-by-side in the bed of a pickup - even a full sized one - is going to be much more of a comfort issue than temperature.

I agree 100%. It won't be comfortable, hygienic, or enjoyable. It will get stuffy pretty quick amd is only one fart away from being a gas chamber.

I'd just get a canvas tent and use a simple propane heater and be done with it.

 

[Alloy]

Price it all out. But I'd sooner add a propane heater like a Propex unit.

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If that was my vehicle most of it would be ripped off or punched full of holes the first summer. What was left at would come off breaking trail in the snow.

RVs use steel pipe on the bottom for propane.

The combustion air pick-up will fill the furnce with dust.

We used to have a generator exhaust come out the bottom. Then we bought a digital CO meter. The CO inside would be 10-15ppm with the generator running. I made one of these.

Camco Gen-Turi Generator Exhaust Venting System

Camco Gen-Turi diverts nasty fumes away from the ground, so they won't be inhaled by neighboring RVers.

www.campingworld.com

 

[Alloy]

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.

For $400 buy 2 coolant heaters and some 3 way valves then one can be the back-up for the other.

 

[Joellivin]

Im going to have to look into the diesel heaters and a good way to mount them or a propane, maybe yall are right that all the water may just end up a mess.

 

[roving1]

Radiant heat is terrible without a ton of insulation. Seems like you would be doing a better job of keeping the truck bed warm compared to the air inside of the truck. Chinesium diesel heater would work better and be 10 times less effort.

 

[ski_bike_camp]

Have a look at Rixen Enterprises. They make a deisel system based on the Espar Hyrdronic furnace. You get hot air, hot water. I have done it twice. Once in my Sprinter and now again in my new truck. It uses air handlers versus in-floor radiant heat.

 

[calicamper]

One thing for is for sure electric to heat is really power hungry. Having said that low wattage heated blankets are about the only efficient way to heat using electricity. Curious to see what you end up doing

 

[greg.potter]

As others have pointed out using hydronic heating for in-floor, radiator based forced air domestic hot water via heat exchangers and engine coolant heating / heat recovery via heat exchangers is relatively common. Trying to make a hydronic system to fit in a pickup bed that is portable / removable would be a significant challenge in my opinion. Of course there is nothing that can't be done given enough time, money and perceverence ...... with the emphasis on the perseverance part.