Does a decent 12V heater exist?

john61ct

Adventurer
Yes recirculating is the way to go. And a precise thermostatic control, unless you rig a button to slap that just keeps it going for X minutes.

Of course the trailer needs to be of a sufficient size

ideally designed for the heating system from the beginning.

And yes very few use cases justify going to this trouble.
 

Alloy

Well-known member
The diesel heaters can recirculate air - in that one can normally plumb the cold air intake (not the combustion intake) into the volume - that's how it's typically done for the truck cabs they were originally designed for.

I think a lot of applications, especially the portable versions, just opt for "simplicity" by only having the hot air ducting to worry about. In the same way that the Propex heaters can have a cold-in duct and a hot-out duct, so can the diesel heaters.
Yes I agree.

It wouldn't take much to make the portable heater cases with an either/or option.....keeping in mind that too much ducting is the same as blowing air into a air tight box.
 

Victorian

Approved Vendor : Total Composites
Yes I agree.

It wouldn't take much to make the portable heater cases with an either/or option.....keeping in mind that too much ducting is the same as blowing air into a air tight box.
it would be easy to have a return air feed. But because you should always have a window cracked anyway for fresh air, it really doesn’t matter . If the camper would be shut tight, then yes it would an issue and the portable won’t be able to blow air into the camper.
 

rholbrook

Member
When we bought our pop-up it had a little propane heater in it. It’s the only part of the original interior we kept. Already have and use propane for the outdo cooktop. A little bit of 12v for the blower and you’re good to go.


Sent from my iPhone using Tapatalk
 

hour

Observer
The are OK for a tent but a poor design for a camper.

The back pressure from blowing air into a sealed camper makes it horribly inefficient.

It needs to draw (not the combustion) air from inside the camper.
I have an all-in-one diesel heater that I replaced my DIY unit with and just bungee flexible dryer duct to the inlet. That then gets plumbed in to the camper through the propane hose outlet (if I were cooking outside) so it's pulling cold air off the floor behind the cabinets. Not the most perfect seal to the inlet of the heater, but that's easy to remedy with a 3" takeoff like I did with my diy one. Staying toasty at 9,000ft asl right now in a pop up camper, same last night with 10*F temps and 35mph gusts. I have my roof vent (no fan) cracked so the abundance of dog farts being produced can go out.

IMO they're perfect for a camper. When I upgrade from a pop up I'll be installing one inside and fitting a quick connect for fuel so I can drop a line in a jerry can outside.. keep all the stink and spill potential out of the camper.

My fuel pump settings are 1.3-3.1hz and fan is 2000rpm min to 3900rpm max. I have maybe 20 seconds of minimal visible smoke on startup at 5,200ft asl (home) and 9,000ft asl.. this seems to keep the case temp warm enough to allegedly curb a lot of sooting. I'm set to 2.5hz right now and case is at 392*F, low 20's outside. I'm consuming 0.97a/13w from a 70ah lifepo4 battery, 96-107w on startup for a whopping 90 seconds.

I got 12 hrs of run time off a little less than 5L last night, bet it would have been longer with a hard sided camper but the wind was penetrating the walls of my pop up. 3kw model. My camper has a suburban propane heater (camper is a 2017) and it's just terrible. Bakes someone's legs if they're on the wrong side of the dinette, bakes you when you sleep and then cuts off for too long. I helped that a little with a fan to stir up air by the thermostat but it's still not a thing I enjoy using. And it uses nearly 50w running, so I'll take 13w all day over that.

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broncobowsher

Adventurer
Just doing the math for 12V heat...
A small space heater, 600 watt (considering the typical home one is 3 times bigger at about 1800 watt).
12V, 100Ah battery. That is a pretty big battery. About 75 pounds in lead acid form. 12V x 100 Ah is 1200 watt-hour of energy. That is also if you completely run the battery flat and plan on damaging the battery. So you really have about 600 watt-hour of energy storage without destroying the battery. Ignoring inverter efficiency (they make waste heat that you want anyway) you can get about an hour of heat from a tiny heater and a big battery.

That is the math on why it doesn't work. If you want heat, burn something.
 

Awkragt

Adventurer
Good replies thanks. This is exactly the math I was looking for. I guess I was looking at a propex and thinking for the extra cost ~1,000 bucks, plus propane tank and gas plumbing. $1,200 bucks buys a lot of Ah. But doesn't matter if you drain 200-400Ah, you'd never be able to recover that the next day.
 

john61ct

Adventurer
Yes, average energy in has to exceed energy out.

All storage does is expand the timeframe for averaging

give you a bigger buffer
 

plh

Explorer
How cold are you camping at? I have a 12DC RoadPro blanket (4.6 amps / hour draw) and used it this past Friday evening while camping in the back of my '05. Outdoor temperature was down to 32F. Takes the edge off and glad I had it. Saturday, Sunday and Monday evenings were only down to the mid 40's & low 50's and I did not need it. I power it with a DIY 120 aH Li-Ion battery pack charged by a 100 Watt flat roof rack mounted panel. No issue for this battery / solar setup to keep phone charged, a couple lights, blanket 1 night and my Edgestar all weekend. It was sunny but 44 degrees north latitude, even sunny isn't great sun this time of the year.
 
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Buddha.

Finally in expo white.
I was going to suggest a small RV propane furnace but then I looked into it. +$800 before the extras and you'd still need a decent sized battery to power your fan. Probably not the best option.
 

67cj5

Man On a Mission
I interpreted the question to mean a 12v powered heater (i.e. a DC-electric heater).

I don't think anyone has created a forced-air DC heater that will do the job. There are a few rooftop HVAC units that include a heating mechanism - with a big enough battery bank and a monster inverter you might be able to power that, but without running the numbers, my instinct (as an Electrical Engineer), is that the power needs would exceed the feasible limits of most battery banks. Certainly such a battery setup would cost more than what a conventional fueled forced-air heater would cost.

You might be able to get by with a 12v electric blanket. Such things exist, and while still very inefficient, at least you're only heating yourself and not trying to heat a whole air volume.
I bought 2 of those 12v electric blankets and some of them are pretty clever, I bought 2 of the mid priced ones, When you power them up they have 3 power levels Lo, Med, Hi. and they have a built in Timer that runs for 45 minutes then it Shuts Off, they also claim to be 45w, They cost £13.99 / $ 19.01c USD.

I plugged One in to the Dometic PLB40 and set it on High the power meter went from 100% down to 94% which means the Blanket used 30.72w OR 2.4Ah, They are made of very soft Fleece and are well made, To the touch you don't feel alot of heat but they do warm the Bed or if you lay on it or lay it on you the heat really comes through and thery are very warm and they measure 59" X 43.3".

All up I am very impressed with everything about them and most of all the power Draw because being 12v it's hard to find anything that works this well without Eating your batteries, But at only 2.4Ah I can put that amount of power it used in under 20 minutes by plugging the PLB40 in to the Cigar Socket when parked or while driving, OR using 2.4Ah from a 115Ah deep cycle battery is barely going to be missed.

QUOTE:-


ELUTO heated travel blanket Warms your body that helps to maintain your Metabolism and Blood Circulation.
ELUTO 12V Warm Cushion in Black Seat Cover is designed with a temperature level to be adjustable. It has a 45 minute timer and it automatically turns off after 45 minutes.

  • Specification:
  • Material: Polar fleece
  • Color: Black and white
  • Size: 60*43.5 inch
  • Volts: DC12v
  • Watts: 45w
  • Weight: 2.3lb
  • Power Cord: 79 inch
  • Usability & 3 temperature settings: the cigarette lighter plug can be connected to the 12 V cigarette lighter socket of a car, truck, SUV or motorhome. 3 temperature settings of high, medium and low to meet different heating needs.
  • Safety: automatic switch-off heat protection is designed to turn off the power supply every 45 minutes. To avoid scalding and increase safety.
  • Soft material and easy to fold: the electric blanket is comfortable and skin-friendly. You will feel very comfortable. It can be folded and stored in the boot without taking up much space.
  • Keep warm: the heat blankets can heat up quickly. It is suitable for road trips, camping, caravans or covering your pets in the car.
  • The electric blanket is 152.4 x 110.5 cm. Each of our products has passed quality checks. If there are sometimes errors, we will handle it properly. No need to worry about product quality.
 

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