APU in a Conversion

Ralph7 · June 28, 2014, 03:28:49 PM

The APU I have has it's own radiator and AC condenser on one end, and AC compressor ( belt driven) AC 110V alt. Belt driven. The unit has a 65amp 12V. alt., !!!
The unit is hard wired direct to the truck (in my case to the house 12V system) . If or when the main 12V alt. fails or sitting ( not running) and the unit is on or the batteries need charging it kicks on.
The 120V. alt has 2 120V. 20A. breakers (1 to the cab) 1 to the block heater.
The AC / heater box in the cab, and the control box are in the cab.
The 2 cyl. diesel runs at 2800RPM and if you use the original exhaust system it is extremely quiet ( less noise than a Honda 1000), have been next to several running units.
It weighs about 300lbs.

?? and DOES not fit in the old condenser bay ,to tall.
I bought mine for the 120V for 1 roof AC on the road.
Mine is a Rig Master imported from Japan, 2 colors of engine paint an names Cat yellow and Perkins, do not know engine mfgr.
In the bus I will need to extend the heater hoses and the AC hoses if I want to use them.
But do not know if I will get any use of them?

?!!!!!
There were 15 each from a Salt Lake city trucking on E-place last fall $2100ea. with 8,000-10,000 hrs...
These are not for power hogs, just for backup for my solar.

luvrbus · June 28, 2014, 03:40:18 PM

Cat and Perkins one in the same it probably has a Cat CO.5 engine

twostick · June 28, 2014, 08:06:57 PM

Rigmaster runs a Perkins 402-05 engine. Perkins is owned by Cat so for an extra $$ Perkins paints their orange engine yellow and calls it a Cat. The ONLY difference is the paint color and it uses a Cat shut off solenoid.

Also it is a Canadian company and as far as I know is still mfg'd in Canada. There was a US branch of the company that was based is Kansas IIRC but that is gone now.

http://www.rigmasterpower.com/home.php

I have one on my truck. It is about 20 yrs old and the biggest complaint I have with mine is the very poorly designed cooling system. The fan is at one end of the engine and it blows across a hot engine, thru the A/C condenser and finally thru the radiator. The cover tends to leak too because it just has foam seals and 2 rubber clasps to hold it shut so you lose airflow there too. No reason that I can see for them to have put the rad at the wrong end of the machine. Their solution on the newer ones was to leave the fan where it was but reversed the airflow and put an electric pusher fan at the other end.

Mine has a smaller engine than the new ones so it only has 4500 watts of 110v power and a 25 amp AC generator (no not an alternator). The new ones are 6kw and a 60 amp alternator. 20k BTU A/C 13.5k BTU heat.

Now all that being said it has over 25,000 hours on it and I replaced the engine a year ago and I have re bearinged the generator twice.

Kevin

Ralph7 · June 28, 2014, 10:00:59 PM

Mine has the V-belts, also has the modified thermostat housing and new plumbing. Also it has the larger oil pan.
Also mine was built in 2004 or 2006. The new ones have those flat belts.

Audiomaker · June 28, 2014, 10:09:18 PM

I went and had a look at that model's spec's and it has an oil change interval of 1000 hours???

Is that a misprint? My generator is ten times that often.

twostick · June 28, 2014, 10:17:35 PM

Quote from: Audiomaker on June 28, 2014, 10:09:18 PM
I went and had a look at that model's spec's and it has an oil change interval of 1000 hours???

Is that a misprint? My generator is ten times that often.

It only holds 4 qts of oil IIRC. Mine holds 2 qts. 500 hr interval.

Kevin

luvrbus · June 29, 2014, 06:25:50 AM

I toured the Cat engine plant in Seguin Tx and saw the Perkins and little Cat engines being made it was interesting to see the 24 cylinder to 2 cylinder engines being made the 2 cylinder Perkins/Cat looked like a paper weight

Audiomaker · June 29, 2014, 09:22:45 AM

Quote from: twostick on June 28, 2014, 10:17:35 PM
It only holds 4 qts of oil IIRC. Mine holds 2 qts. 500 hr interval.

Kevin

My Kubota D905 hold 4 quarts and has a 100hr oil change recommendation, which is not unusual.

So what changed?

TomC · June 29, 2014, 08:34:27 PM

If you want to convert generator hours to miles for reference, most use 40mph. Hence 100hrs would be like 4,000 miles-not bad for a small engine. On my Mercedes 300 TurboDiesel, I change it every 3,000miles rather then the 5,000mile that are suggested. And because of that, at 461,000miles (original engine and transmission), it still runs like a top (even my mechanic can't believe it) and doesn't burn enough oil to add in between oil changes-it probably leaks more then it burns-but then I don't have to worry about rust. Good Luck, TomC

Audiomaker · June 30, 2014, 07:46:59 AM

Quote from: TomC on June 29, 2014, 08:34:27 PM
If you want to convert generator hours to miles for reference, most use 40mph. Hence 100hrs would be like 4,000 miles-not bad for a small engine. On my Mercedes 300 TurboDiesel, I change it every 3,000miles rather then the 5,000mile that are suggested. And because of that, at 461,000miles (original engine and transmission), it still runs like a top (even my mechanic can't believe it) and doesn't burn enough oil to add in between oil changes-it probably leaks more then it burns-but then I don't have to worry about rust. Good Luck, TomC

Well right Tom, but at the APU link posted above, the brochure for the APU states the oil change interval at 1000hrs (or 40,000mi).

That's with a motor running 2800rpm. If it's not a misprint, it would make one curious no?

TomC · June 30, 2014, 09:09:52 AM

On some of the APU's the manufacturers have increased the oil capacity to better coincide with the oil change interval of the big engine. For instance, the Detroit DD engines when used over the road have a recommended oil change of 50,000hrs. At an average of 50mph, that works out to be every 1,000hrs. But many times, the generator and big engine will not have the same run time. I changed my Onan 6.5 Emerald Plus Commercial (gasoline 2 cylinder @ 1,800rpm) at 150hr intervals and got 12,000hrs life out of it. Most of us just change everything once a year. Good Luck, TomC

Audiomaker · June 30, 2014, 10:18:19 AM

Not to hijack the thread, but I guess it's related...

I suppose the generator manufacturers are generous with your wallet when it comes to increasing their longevity stat's.

My generator runs 10hrs/day (inverting the rest of the time). That's an oil change every 10 days or 3 times a month @ $30/gal/change for me.
I've been running synthetic and have drawn that out to about every 2 weeks (2x per month)... still expensive.
Man, I'd love a 1000hr interval (every 100 days).

Oonrahnjay · June 30, 2014, 10:56:28 AM

Quote from: Audiomaker on June 30, 2014, 07:46:59 AMWell right Tom, but at the APU link posted above, the brochure for the APU states the oil change interval at 1000hrs (or 40,000mi).

That's with a motor running 2800rpm. If it's not a misprint, it would make one curious no?

Using 5W-40 full-synthetic oil, (Rotella 6 or Mobil Turbo-Diesel), the listed oil change on my VW TDI engine is 10,000 miles. If you don't do a lot of in-town driving and pull an oil sample at 10K, the analysis will come back "your oil is only (.. 40 to 60% ..*) used up -- continue to run it". With the right oil, I'm thinking that 1000 hours on a governed speed engine sounds reasonable - long but reasonable.

*This number is variable but it's almost always in this range.

Bruce H NC USA