I'm in the planning stage of building my next RV tow rig and I've been considering installing an APU instead on an on-board generator. The purpose would be to provide air conditioning and heat in the tow rig when parked and to provide AC power to the travel trailer when dry-camping at a truck stop or while driving down the road (to power the trailer AC, etc.). I know that they aren't cheap so I'll definitely be looking to buy used but I'm not sure what to look for or watch out for. Does anyone have any experience that they care to share?

 

An aircraft APU? how much would even a used (working) one cost? Cool idea though I have to say.
Let us know what you come up with.

 

I think he means a semi truck APU.
BTW. in california not only are you allowed to idle your engine for heat/ac/electric, but if you have an 08 or newer engine (W particulate filter & such), your APU has to have this stuff too or you are not allowed to use it either!!

 

And they are about to retro this for all APU's 2006 and newer. They are going to outlaw older APU's unless they have been retrofitted with a DPF.

The law says you can run the APU through the trucks DPF, But then the federal law says you can't modify the trucks exhaust system.

So its the EPA at its finest.

 

Other than the Indian guy at the Qwicky Mart on the Simpson, what's an APU?

 

Auxiliary power unit!

 

Based on my limited research, an APU for a semi truck is a small, 2 or 3 cylinder diesel (Kubota and Yanmar are popular) that powers an AC generator (3-6KW) and runs the heat and an air conditioner for the sleeper. Most of them seem to run off of the truck fuel and batteries. A few seem to be able to hook into the truck cooling system to preheat the coolant.

Apparently, adapting them over for RV tow rig use isn't too common.

 

12v,what do those APU thinges weigh and how are they physically sized?

 

A couple hundred pounds.

Check out this example:
http://www.comfortmaster.com/truckap...kapu_specs.htm

If I bought one, I would make sure it preheats the coolant - great for the winter/best block heater ever. Some folks up here (especially prevalent in the oil industry and heavy equipment) add diesel fired coolant heaters - they use battery power to run an igniter and pump. Many have timers and controls to turn on the cab fan to heat the cab. It's what you need when the equipment operates where it can hit -80F (no typo).

 

There are a large number of RV generators on the market to cover just about any need. Why not use what has been proven and would seem to be a lot simpler?

Jim

 

I could do that but in addition to buying a diesel RV generator, I also have to buy a RV or some sort of stand alone A/C system, and some sort of stand alone heat system and then make it all work together - or - I can buy an APU that was designed to do all three and adapt it to my tow vehicle. I'm hoping that the APU will end up being less money and work in the long run.