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-   -   On Board Generators in Classic MH's (https://www.airforums.com/forums/f159/on-board-generators-in-classic-mhs-216191.html)

PeterH-350LE 10-30-2020 08:19 AM

On Board Generators in Classic MH's
 
The only replacement generators available now are Onan EVAP or CARB and come in a housing that in most cases exceeds the compartment size by several inches. Box modifications are difficult or impossible due to adjacent objects.

Other than maintaining our existing generators, what options do we have?
Keyair posted comprehensive links to manuals here:

https://www.airforums.com/forums/f31...ead-95034.html
Additional thoughts, suggestions and repair procedures are appreciated.
I.e.:

you can buy spark plugs from onan for the6.5 NHEF for an inflated price or get the very same Champion Copper Plus CHP 909 for $1.98 at the auto part store.

Magnet18 10-30-2020 02:28 PM

I thought i measured at one point that two smaller honda inverter generators tied together would fit in there


If you've got the desire that generator compartment will hold quite a few lithium batteries and a whole-rig inverter/charge controller

PeterH-350LE 10-30-2020 03:15 PM

Quote:

Originally Posted by Magnet18 (Post 2427786)
I thought i measured at one point that two smaller honda inverter generators tied together would fit in there


If you've got the desire that generator compartment will hold quite a few lithium batteries and a whole-rig inverter/charge controller


To supply a 30/20 amp service, don't think so...or am I so far behind in new technology?

Magnet18 10-30-2020 03:53 PM

Quote:

Originally Posted by PeterH-Airstreamer (Post 2427800)
To supply a 30/20 amp service, don't think so...or am I so far behind in new technology?

Referring to the generator or the lithium?

PeterH-350LE 10-30-2020 03:58 PM

Quote:

Originally Posted by Magnet18 (Post 2427814)
Referring to the generator or the lithium?

both, 2 honda 2000 only give 4k, so max 30amp, no remote start no real exhaust solution, no fuel solution. No idea what lithium can provide.

cummins/onan is the only RV generator supplier left at this time.

Magnet18 10-30-2020 08:31 PM

Quote:

Originally Posted by PeterH-Airstreamer (Post 2427818)
both, 2 honda 2000 only give 4k, so max 30amp, no remote start no real exhaust solution, no fuel solution. No idea what lithium can provide.

cummins/onan is the only RV generator supplier left at this time.

According to my tape measure, 2x honda 3000s would squeeze into mine. It would be tight, and exhaust would need solved, but it would meet all my energy needs (2x 30A outputs)


For lithium, an inverter like this would provide all your power needs except aircon, it *can* run an AC if you've got a massive battery bank and a lot of solar and direct sun, but you will really be pushing it. Give it just a couple more years, the cruising sailboat industry is really pushing for it and some are doing it, but it's bleeding edge still. The raw DC current alone starts to be a challenge.

https://gpelectric.com/products/ic-s...erter-charger/

The battery bank is limited only by your budget and/or willingness to rip up a wrecked tesla. 6 car-batteries worth, @100AH apiece (and @ $1000 a piece) is enough to run a microwave or space heater full blast for 4+ hours, or run your normal-minus-AC usage for multiple days.

Of course it needs recharged, which can be done with a high capacity alternator, or solar, or shore power, depending on your use case. A few hundred watts of solar on the roof is enough to refill each day in most circumstances.

Assuming you can handle your cooling with fans and have a few BOAT dollars to burn, lithium + solar is a very viable generator replacement option, and getting better each year. If my generator blew I'd very seriously consider it.

(Plus it's silent. Plus it has a zero percent chance of carbon monoxide poisoning you :) )

Streamracer 10-31-2020 12:35 PM

I would NOT PUT any gen set into a compartment that is not designed for enclosure, rv. Many people have been aphixated from doing that. Watch craigs list for used ones to use or for parts. Which model do you have? I might have some parts.

willhenshall 10-31-2020 03:28 PM

Jumping in to this thread!

So, I'm just about to dive into the necessary replacement of the now unreliable 30 year old Onan Emerald 3 6.5k generator in my 1990 345LE . The challenge is that the bay/compartment for this is only 24.5" length, and the new Onan 6.5k QG is 34" long, so the install will involve a lot of adjusting and fabrication. Possible indeed. Just takes time and money to fit it in.

But, I've been thinking about a completely different option, which might be viable now, and I'd love the Airstream community's thoughts on this...

So, market forces related to electric vehicles are bring the costs of lithium batteries down and efficiency up. For instance I bought a group 27 'deep cycle' lithium battery for close to $1300 3 years ago from Nex Gen, and now the same equivalent is $875. And it's fair to assume this trend will continue. Expect costs to halve again and to halve again over the next 5 years.

So what I have started to explore is whether a large lithium battery bank plus a high capacity inverter charger is viable now to run ALL my energy needs. I could install today 2400 amp hours of lithium batteries with 1000w of solar to charge it (I would use the now un-used generator bay to fit extra batteries, and use a couple of other internal spots (ie under the sofa) to add the rest - noting that the new generation of Battle Born or similar batteries can be safely mounted in any position, and have no maintenance, and last 10-12 years.

So the big questions would be how to charge this sizable battery bank without a gennie, in addition to the solar? And how would I deal with the AC?

Well there is a massive power gas engine available (grin) so I could beef up the stock alternator to say a 255 amp or more and beef up all the DC wiring from that to the battery bank, so I could run the chassis engine and charge at idle while parked. And of course I could plug in to shore power whenever that's an option.

If I think about how the coach is currently wired, I would replace as many things as possible that currently need 120v with 12v equivalents - all the lighting, replace the refrigerator with a 12v/propane option, obviously keep the inverter to run the microwave and the tv/theater system and the wife's hair curlers (!)

But the big energy hogs are the original stock AC units. These wouldn't run even on this big system longer than a few hours. But there are 12v AC roof top options such as these https://www.webasto-comfort.com/en-u...rconditioning/ and there are other domestic 12v AC systems for off grid living. Another option I have thinking about is installing something like this for the main AC - uses about 900w to run - https://www.hotspotenergy.com/solar-...ot-ACDC12C.pdf - the outside unit could be mounted in the rear bay with careful airflow, and the inside unit mounted on the inside wall in the middle of the coach.

Or there are other new 120v much more efficient RV AC units available now, such as this https://www.recpro.com/rv-air-condit...ote-non-ducted

Anyone else here thought this through?

Best to all, and glad to be back!

Will Henshall

PeterH-350LE 10-31-2020 05:50 PM

Quote:

Originally Posted by Streamracer (Post 2428023)
I would NOT PUT any gen set into a compartment that is not designed for enclosure, rv. Many people have been aphixated from doing that. Watch craigs list for used ones to use or for parts. Which model do you have? I might have some parts.


My model is a 6.5 NHEF . It runs great @1250 hours, except for the exhaust manifold. When the 350 was unloaded from a trailer they scraped the muffler. When i replaced it I found the manifold flange connection was broken. I temporary fixed it by inserting a pipe, but i know that causes some exhaust restrictions and possible leaks.

PeterH-350LE 11-01-2020 07:35 AM

In my quest for a replacement generator, I am looking at a Onan QG 4kw
with a required cabinet size of 14.4"x20"x30.5"
The 350 Generator compartment has a length of 29", making a mod possible.

The 5.5 /7.0 models require appr. 35", which would be a real chore to create without increasing 1 of the dinette benches or modifying the couch.

Realistic considerations for power needs are:
1. How often would I boon dog with the need to run both A/C's via a generator capable of handling the load? Activity can be isolated to area used. A manual transfer switch can be installed to use front or rear AC.

2. Main use of generator is driving in the summer with the front roof AC (and bedroom door closed)
3. Less weight (100 pounds) and less fuel consumption
4. Additional 30 amp shore power already in place for rear A/C
5. Future expansion via 12V cooling solutions (thanks for the link Will) and lithium battery banks

6. upfront cost difference of almost $2k (Onan 4k versus Onan 6.5K)
Thoughts/suggestions?

Magnet18 11-01-2020 08:11 AM

Quote:

Originally Posted by Streamracer (Post 2428023)
I would NOT PUT any gen set into a compartment that is not designed for enclosure, rv. Many people have been aphixated from doing that. Watch craigs list for used ones to use or for parts. Which model do you have? I might have some parts.

I have 3 family members that were found unconscious and airlifted, and are only alive by extreme luck. They were using their oem rv generator as intended and as it was supposedly "designed". There is no magic design, all they do is route the exhaust out of the enclosure.

I guarantee you, airstream did exactly zero wind tunnel testing to verify that the exhaust could never leak into the cabin regardless of wind direction and speed. Nor did they do long term fatigue testing to verify their muffler hanging system wouldn't cause fatigue cracking of exhaust parts after 100,000 miles like a real exhaust system designer would be required to. They hooked up some pipes and called it a day.

Imo, trusting 40 year old exhaust parts carries the same risk as trusting an aftermarket or custom welded exhaust routing kit - the risk both ways is very high, you're making your own judgement call about your safety every time you turn it on.
(And also imo, you should never sleep with it running, no matter how much you trust its design.)


There are a couple of bolt on exhaust extension kits out there for the hondas.

PeterH-350LE 11-01-2020 08:20 AM

Quote:

Originally Posted by Magnet18 (Post 2428276)
...

I guarantee you, airstream did exactly zero wind tunnel testing to verify that the exhaust could never leak into the cabin regardless of wind direction and speed....


Nor did Airstream ever assure that there are no openings in the floor that would allow fumes to enter and that is in trailers and Motorhomes.
On my 350, the passenger side wheel well had an opening big enough for big critters to come and go. On the drivers side, just behind the generator exhaust pipe, I found quarter inch cracks that destroyed the flooring from moisture, Chris reported the same on his 91 350. On trailers I have found holes cut twice the size needed for a pipe, without any insulation or sealant. So yes, the stationary use of generators is very risky without some venting system
https://www.campingworld.com/camco-g...tem-14041.html

cmadmaxman 11-02-2020 10:31 PM

4 Attachment(s)
Hey Peter

You can get the exhaust manifold from Colburn power systems, and most of the parts that you will need. Our manifold number is 154-2541, pricy at $341.81, but much cheaper than a new unit to try and shoe horn in the spot.

I had planed to put my new 7.0 EFI Onan in the Zephyr, but like you found our our area does not allow a unit with the muffler inside the enclosure, let alone a fully enclosed generator unit!

If its running good, might want to think of taking it out and do a complete service. Nice we don't have to worry about points!
I did the heads, carb service, and intake clean up. I took it off to make it easer to adjust the lifters. Colburn had everything I needed to do the work, all OEM.
Found out when I did the heads, someone had reused a head gasket, and it was tore and loosing compression! Unit has somewhere around 1100 hours.

Purrs like a kitten now, well lets say much better that it was!:cool:
Attachment 382481

Attachment 382482

Attachment 382483

Attachment 382484

willhenshall 11-03-2020 10:39 AM

1990 345LE - gennie relacement
 
1 Attachment(s)
Finally figured out the first step in getting the power going reliably in the coach. I just ordered an Onan QG 5500 Commercial EFI generator - the same one used on a lot of movie sets here in LA.

I plan on keeping my 345LE and am utterly sick to death of futzing about with unreliable Onan generators - I've had several RVs over the years with various Onans, my most recent experience was a super low hours 2.8 Microlite in a Roadtrek 190 which even after a complete out of the vehicle rebuild still stopped randomly at least once every few of hours. So I decided to bite the bullet and get a pro option. I work remotely (I run a software company) and I know I will be in the coach a lot.

So, the next step is how am I going to shoehorn this into the existing gennie compartment? The 30 year old generator is an Onan Emerald 3 6.5kw - (it's been fully serviced recently, new carb, new fuel pump, new fuel line etc - I'll be selling it if anyone is interested by the way, it runs ok), but the Emerald 3 is 28" long and the new 5500 is 34" long.

There is room to extend the steel generator box 5" to the front and 4" to the rear. This will involve cutting the floor under the sofa and moving the left box side left 5" and cutting the floor on the right side under the kitchen booth seat 4" and moving the right side inside side 4" and fabricating new steel and soundproofing around that (not that the new gennie needs much if any sound proofing)

Anyone else done this?

Will

PeterH-350LE 11-03-2020 04:00 PM

Quote:

Originally Posted by willhenshall (Post 2429092)
Finally figured out the first step in getting the power going reliably in the coach. I just ordered an Onan QG 5500 Commercial EFI generator - the same one used on a lot of movie sets here in LA.

I plan on keeping my 345LE and am utterly sick to death of futzing about with unreliable Onan generators - I've had several RVs over the years with various Onans, my most recent experience was a super low hours 2.8 Microlite in a Roadtrek 190 which even after a complete out of the vehicle rebuild still stopped randomly at least once every few of hours. So I decided to bite the bullet and get a pro option. I work remotely (I run a software company) and I know I will be in the coach a lot.

So, the next step is how am I going to shoehorn this into the existing gennie compartment? The 30 year old generator is an Onan Emerald 3 6.5kw - (it's been fully serviced recently, new carb, new fuel pump, new fuel line etc - I'll be selling it if anyone is interested by the way, it runs ok), but the Emerald 3 is 28" long and the new 5500 is 34" long.

There is room to extend the steel generator box 5" to the front and 4" to the rear. This will involve cutting the floor under the sofa and moving the left box side left 5" and cutting the floor on the right side under the kitchen booth seat 4" and moving the right side inside side 4" and fabricating new steel and soundproofing around that (not that the new gennie needs much if any sound proofing)

Anyone else done this?

Will


If the 345 space was designer anywhere like the 350, you also will have to cut out some 1"x1" framing in front and rear to extend the box. I do not think it will have any bearing on structural components, since they appear to only serve the mounting of the generator box via a few tack welds. You certainly have more room to expand than the 350, because of the dinette


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