M1079 box heater operation using truck power?

[AKPacker]

Is there a way to operate the M1079 box heater using power supplied by the truck? The directions in the TM are pretty sparse and it sounds like it may need an external power source, but I thought I read somewhere that it was possible to run the heater using power from the truck.

 

[GeneralDisorder]

Not worth it. It's very high power draw. It's designed to operate with a trailer mounted gen set. Inefficient 1980's technology.

60,000 BTU's. It's mad overkill. Improve the insulation and the windows and use one or two of the Chinese diesel heaters inside the cavity that it occupied.

 

[Third From Texas]

Mine is sitting on the garage floor.

Even when it was installed and working as intended, it was absolutely not viable due to the noise. You'd have to sleep with noise protection.

But no, I had to run the genset to operate it. You likely couldn't carry enough battery to run the thing off any sort of converter.

 

[MatthewWBailey]

Insulation is the solution to most if not all thermodynamic problems. And usually the most ignored/dismissed design feature.

 

[Third From Texas]

Insulation is the solution to most if not all thermodynamic problems. And usually the most ignored/dismissed design feature.

Agreed.

The AAR shelters on the M1079 are one big thermal bridge. I've put a heat gun to the walls and seen it match the outside wall in direct sun. I'm adding a 1.5 inches of Sika board in the walls. It (along with the wooden framework) is merely to sever the thermal bridging but it's an extra 9.6R as well. The floor is plenty thick at 3" and the underlayment and vinyl floor planks break the bridge there (and it's shaded 24/7 under the truck). For winter I've placed electric floor heating pads. I'm hoping the solar panels will provide enough shade on the actual roof. But I've left the ceiling open to adding the same concept as the walls if needed, but I don't think it will be required.

The overhead compartments forward (a/c, heat) are just bare aluminum sheeting and I'll be adding an external layer across the outside (as well as the internal Sika wall inside).

 

[AKPacker]

Thanks all, further insulation and a more appropriate box heater are in the plans. I was hoping to find a way to make use of the stock heater this winter until I get a chance to replace it, but it doesn't sound like it is worth the effort.

Agreed.

The AAR shelters on the M1079 are one big thermal bridge. I've put a heat gun to the walls and seen it match the outside wall in direct sun. I'm adding a 1.5 inches of Sika board in the walls. It's merely to sever the thermal bridging but it's an extra 9.6R as well. The floor is plenty thick at 3" and the underlayment and vinyl floor planks break the bridge there (and it's shaded 24/7 under the truck). For winter I've placed electric floor heating pads. I'm hoping the solar panels will provide enough shade on the actual roof. But I've left the ceiling open to adding the same concept as the walls if needed, but I don't think it will be required.

The overhead compartments forward (a/c, heat) are just bare aluminum sheeting and I'll be adding an external layer across the outside (as well as the internal Sika wall inside).

View attachment 930120

Nice work, what did you use to attach the framing to the walls? I noticed just how bad the thermal bridging was this last weekend when camping in cool weather. In the morning you could see all of the box's internal framing outlined with major condensation buildup.

 

[Third From Texas]

what did you use to attach the framing to the walls?

Rivnut fasteners

 

[GeneralDisorder]

I will be firing out my walls similar to Third, but I sprayed it all with Lizard skin and that stopped a TON of the thermal bridging. The interior skin temps went down by 20 degrees. Well worth the effort IMO.

Also the stock windows are (unfortunately) total garbage and will sweat also. At least one of mine had a leak at some corner also......

 

[hike]

I'm hoping the solar panels will provide enough shade on the actual roof. But I've left the ceiling open to adding the same concept as the walls if needed, but I don't think it will be required.

I would argue that insulating the roof is at least as important as the sides, even with the solar shading. The shading will greatly reduce radiant energy gain, though will do little for conduction and convection gains during hot times, and nothing to reduce condensation at the ceiling's thermal bridge points.

 

[Third From Texas]

I would argue that insulating the roof is at least as important as the sides, even with the solar shading. The shading will greatly reduce radiant energy gain, though will do little for conduction and convection gains during hot times, and nothing to reduce condensation at the ceiling's thermal bridge points.

As I said, I've left it as an option.

I originally drew up a way to do it with a 6x10 segment that just bolts to the ceiling. I would also contain the ceiling lights. It'll be an easy enough mod to slap in if needed.

 

[AKPacker]

I will be firing out my walls similar to Third, but I sprayed it all with Lizard skin and that stopped a TON of the thermal bridging. The interior skin temps went down by 20 degrees. Well worth the effort IMO.

Also the stock windows are (unfortunately) total garbage and will sweat also. At least one of mine had a leak at some corner also......

View attachment 930131

What windows did you go with and are you happy with them? I've been eyeing the Tern Overland windows, but they sure cost a pretty penny.

 

[GeneralDisorder]

What windows did you go with and are you happy with them? I've been eyeing the Tern Overland windows, but they sure cost a pretty penny.

You don't need to buy overpriced, plastic, tiny "RV" windows because our boxes are not plastic and fiberglass crap. The "RV" windows have rounded corners to prevent the plastic skin from cracking at stress points. Not an issue with our all aluminum construction.

My windows are custom sized black Milgard Trinsic double-awning windows with a Z-bar frame. They were approximated $4,000. About 8 week lead time:

M1079 window upgrade (small window van)

Swapping out my small windows for something more suitable to it's new life. Got the door window installed and the passenger side wall upgraded. I'll be masking the glass and going over the outside with CARC so they look factory. Might figure out some drop down canvas covers for them as well.

www.steelsoldiers.com

They are VERY high quality, Double-insulated, e-coated, etc. Best thing I have done to my box.