I think it's time for all of us to admit that we're lying about how easy it is to heat our trucks with diesel fired bunk heaters. It's clear that Steve the Scientist is correct, no matter what.

But here's some science for Steve. How many BTU's does it take to effectively heat a truck? To calculate, let's assume a standard size stand up sleeper and cab, poorly insulated (in other words, Steve's truck).

The approximate measurements would be 11'X8', giving us 88 sq ft. To calculate how quickly the heat will be lost (to determine how many BTU's we need to replace that lost heat), we first need to determine the efficiency of the space. Trucks are known for having poor insulating qualities. In a space where there is little to no insulation in walls, ceilings, or floors, uninsulated windows, and the windows and doors fit loosely, the expected BTU loss rate is 90 to 110 Btu/hr/ft2 Since we already know that our square footage is about 88 sq ft, we find that we need 7920 to 9680 BTU's per hour to maintain the temperature of that space.

The point is that it depends on the type of heating system, air exchange rate, insulation, window and door quality, location, and temperature settings to determine the correct amount of BTU's needed to heat a given space, as all of those forces are working AGAINST the heating system. A diesel fired bunk heater with an efficient fan for moving air will heat a space far easier than a ceramic heater that has no air displacement system. The more efficient the heating system, the better it will heat. The less efficient the space, the more BTU's you will need to heat that space. It's clear that Steve has an inefficient or malfunctioning heating system, or a poorly insulated truck.

 

On my Marten truck they put a APU and a bunk heater. Right now I'm in Wisconsin and the only thing running is the bunk heater and these things do get damn hot. Usually it's running slow with just a little whine from the fan. The only time the APU runs is for the air conditioning or if the batteries get low when I'm sitting all day with the heat on, cell phone charging, bluetooth charging, computer charging, watching tv, running the microwave and have the lights on. It will run for a short time and charge the batteries back up then shut down. Other than that it doesnt run. Once in a while I'll start it just to make sure it works because it hasn't ran in several days.

Think about how much less maintenance you'll have to do on your APU and how much longer it will last until a overhaul is needed when you don't have it running as much. I've only put 12 hours on the one on my truck in the past 3 weeks. Most of those were for air conditioning while I was in Southern Texas. Anyways, this is just my experience with them. 8) 8) :wink:

 

By the way Steve I enjoy reading your thread. Thanks for sharing your adventures on the road and in business.

 

One thing I would like to point out while I read this about the bunk heater/APU debate which I have found informative (I never knew about the bunk heater) is that these APU's have a comfort monitor. So for me I set the heat on the highest level and when it reaches that level it shuts off so I don't think it's accurate to multiply the fuel usage times 10 hours a night. Mine doesn't run all night long.

But definitely I can say that even with the thing on high it doesn't seem to be heating the truck like those bunk heaters. But I close the middle curtains and only heat up the immediate bunk area so it works for me.

 

I think I'm gonna recind my admittance of wrong(not that it was genuine to begin with),I think after further evidence I was proven correct. 8)

 

Yup, I have the comfort mode also which I use. Just set the temp you want and it turns on and shuts off automatically. Keep in mind that with an APU you need to put a load on the engine to generate more heat. I wired my APU block heater cord permanently to the engine so I don't have to plug it in every night. I also put a switch inside the cab to turn it on and off. In the summer you don't want to have the block heater on. Mine uses .2 gallons per hour at full load and .1 or less at just heater mode.

I measured the temp of the heater and without a load it's 120 and with a load it's 180. You can also plug in anything that needs 110v to cause a load.

As far as maintenance on the Rigmaster, there is none other than change the oil every 1,000 hours of operation. It has a 3 quart oil pan which is massive for that size engine.

I've run my batteries down to a critical level and my truck almost didn't start. That's one thing you don't have to worry about with an APU. It monitors the battery level and starts up automatically whereas bunk heaters do not and they also drain your batteries to supply current to the fan.

I got my Canadian/US Paps and Pars stickers so I should be all set for any trips up to Molson country.

Not a bad run for the past week. 3600 miles total. Out to Kansas then back home the LONG way. I felt like the mail man once again delivering multiple drops.

I'm going to get new drives put on probably tomorrow and going with those Bridgestone 726EL. I think that's the model. I wanted the 720's but I guess those aren't for long haul trucks. They look really meaty though!! Nothing else to do on my truck other than that and hit the road again.

Time to head off to Wally Mart and restock my supplies.

 

Buddy of mine just came in off the road all p*ssed off. Rig Master, 3100 hrs, hole in piston. The little Perkins died.

Getting a little Cat this time, he thinks it is a Perkins with yellow paint. But he thinks having Cat back this one might be helpful?? He will be close to $3,000 after a couple up grades.

 

At 3100 hours isn't it still under warrantee ?? Why 3000$ to fix it ??

 

The Perkins engine is the exact model that goes in most yachts. That must be just an isolated case. He should have bought the extended warranty. I did and it was cheap.

 

Kind of like the engine. :lol: