Onan + UHG in a RT Popular

[bwolfsohn]

Has anyone added a UHG to an RT on a chevy chassis that has an onan ?
I looked at a video of an Onan in operation the other day, and the volume would drive me nuts, as well as being unwelcome in manysituation. But, there are times when it looks like it the Onan would come in handy...
Just looking at options in my search for my future used RT.

[booster]

Originally Posted by bwolfsohn

Has anyone added a UHG to an RT on a chevy chassis that has an onan ?
I looked at a video of an Onan in operation the other day, and the volume would drive me nuts, as well as being unwelcome in manysituation. But, there are times when it looks like it the Onan would come in handy...
Just looking at options in my search for my future used RT.

We did in our 07 190P Roadtrek. We also added batteries a bit later. It wasn't long before the Onan, which we had not used much before adding the UHG, didn't get used at all. We took it out and sold it.


IMO, about the only thing you need an Onan for is air conditioning. Everything else can be handled pretty easily with batteries, solar, and a big alternator setup.

[bwolfsohn]

Originally Posted by booster

IMO, about the only thing you need an Onan for is air conditioning. Everything else can be handled pretty easily with batteries, solar, and a big alternator setup.

Living in Florida, air conditioning is a big thing..

[bwolfsohn]

Originally Posted by booster

We did in our 07 190P Roadtrek. We also added batteries a bit later. It wasn't long before the Onan, which we had not used much before adding the UHG, didn't get used at all. We took it out and sold it.

Booster,

thanks for the feedback..

What was involved in adding the uhg (batteries, electrical, etc) ? who did it ? approx cost ? road clearance issues ?

[SteveJ]

I replaced my Onan with a remote start Champion inverter genny. You will either have to mount it on a carrier or do like I did, mount it on a trailer I always bring. The trailer contains a motorcycle and related gear.

On TDY near Torey UT near ut12, my all time favorite road.

[booster]

Originally Posted by bwolfsohn

Booster,

thanks for the feedback..

What was involved in adding the uhg (batteries, electrical, etc) ? who did it ? approx cost ? road clearance issues ?

Nearly all of our changes to power systems are here on the forum, so searches should help you find them.


As for the UHG in a Chevy. No ground clearance issues as it sits up higher on the engine, but it also runs hotter there. If you have a 2007 or older, you can do a parallel install with the original alternator and save some money.



Can be put on as a DIY, but is not an entry level job.



Not cheap, you can see the pricing on the Nations Alternator site, but expect a couple thousand dollars for all the parts.


Wiring to the batteries would need to be upgraded to 4/0 cable.


4 AGM golf cart batteries gives 440AH, but that will not run your AC for more than a couple of hours.


Upgrading the shore charger and adding solar if done is extra.


Fabrication needed to hang batteries underneath, or you have to sacrifice rear storage (lots of it).


If you need to run the AC for extended times, you would have to run the van engine a lot, and still might not keep up.


As mentioned, if you need all night AC, or all day for that matter, IMO the Onan is the only way to go, except for switching to a quieter portable generator and living with it's shortcomings.

[dvrdwn]

So it's not possible to run a typical class B A/C on the UHG alone? Assuming you have the biggest UHG available.

[BBQ]

Originally Posted by dvrdwn

So it's not possible to run a typical class B A/C on the UHG alone? Assuming you have the biggest UHG available.

Not the run of the mill UHG.

All the alternator specs give you the best case scenario (ie lab condition) output figures.

If you factor in engine speed (usually at idle, not at test max), degeneration due to heat absorption, etc., the real-life output is quite dismal.



ps. you won't want to drive the alternator at test lab speed for hours so that you can run your aircon. You will ruin your engine. $$$

[booster]

Originally Posted by dvrdwn

So it's not possible to run a typical class B A/C on the UHG alone? Assuming you have the biggest UHG available.

There is a bit of disagreement on this topic, partly depending on how the system is setup.


Theoretically, the UHG can run the AC indefinitely as long as the motor of the van is running as it will produce enough power to do that. But that is kind of a non starter in a lot of ways and would mean the van would be running all the time in hot weather. On top of that, most system aren't set up that way. They use an autostart to run the engine when the batteries get to a certain discharge level, and at that point the UHG has to run the AC and charger the batteries. The largest of the UHG units would be a 280amp version that will net about 165ish amps when hot, but probably a bit lower at idle speeds. That load is not enough to catch the batteries up and run the AC for the timing that most of the setups use and the system can go into the so called "death spiral" of losing a bit of battery state of charge on each cycle until the batteries are dead and the system shuts off. Many systems also limit the number of timed cycles also before the system shuts off.


Others here will be able to fill in the blanks about the times and brands, but I think most would agree that the normal Nations/Balmar UHG setup if very iffy to get continuous AC with most setups. You would likely need at least 800+ah of batteries to make it overnight without the van running and then you would need something above 4 hours of driving to recharge the batteries, every day.



If you are going to have the van running most/all the time, you might just as well use the dash air and forget the coach AC unit.


It can get very expensive, very quickly, to try to get continuous AC availability without a standalone generator.

[bwolfsohn]

I'm also looking for a rear setup ahat might allow me to create an office ion one of the forward bunks. (see precious picture...)

[bwolfsohn]

previous.. not precious.. damn autocorrect...

[genecusano@yahoo.com]

Originally Posted by booster

We did in our 07 190P Roadtrek. We also added batteries a bit later. It wasn't long before the Onan, which we had not used much before adding the UHG, didn't get used at all. We took it out and sold it.


IMO, about the only thing you need an Onan for is air conditioning. Everything else can be handled pretty easily with batteries, solar, and a big alternator setup.

Did you do it yourself?

[booster]

Originally Posted by genecusano@yahoo.com

Did you do it yourself?

Yes, we did all the power upgrades ourselves, inverter/charger, solar, UHG, batteries, etc. There are a couple threads on the forum here with the documentation of the changes.