Adding generator to Fifth Wheel

Stefonius wrote:
I'm sure there's a premade accessory for that somewhere in the Onan catalog. If I can find the documentation sent to me by my RV manufacturer, I'll PM you a copy.

Nice looking installation, by the way. I'm interested in following its progress.

thanks.. my installation so far looks like the empty enclosure (second pic). the genset is on a flatbed cart in the shop.

I'm sure there's a premade accessory for that somewhere in the Onan catalog. If I can find the documentation sent to me by my RV manufacturer, I'll PM you a copy.

Nice looking installation, by the way. I'm interested in following its progress.

Stefonius wrote:

sdetweil wrote:

Stefonius wrote:

sdetweil wrote:
is your FW generator prepped?

Sadly, no. I called the manufacturer and spoke with one of their engineers. He told me that all of the generator prep is done with a specific list of parts obtained from Cummins/Onan, and sent me a copy of the list. Basically, it's a metal box put inside of the front compartment, a mount from which the genset hangs, a transfer switch, a higher flow LP regulator, LP supply lines with larger inside diameter, and a remote start switch with hour meter.

Any of the Cummins/Onan service outlets nationwide can do the installation, as they have the parts. This is the quietest and safest way to go. The unit is designed to get intake and cooling air from underneath, and the exhaust pipe runs under the compartment and opens on one side of the RV. I'll put a Genturi stack on when it's in use, so that I don't have to worry about it.

I am installing an Onan 7kw genset in my non-prepped FW as we speak. I have the floor cut template, got the box built, have run the power cord from the genset location to where the ATS will be (and power mgmt/suppressor box) (have both boxes now), just thinking thru the genset mount.. I'd love to see any info on that 'mount'.

I converted my unit to LP. and will use the Onan EC30W wireless remote start kit as it adds a set of function over the wired remote start.

edit: I have called both the local Onan office and Camping World 3 times each for estimates on the install, and they do not return call as they promise or remember that I did call before.

I got my information from the manufacturer of the fifth wheel. They gave me the Cummins part number, and I was able to look it up that way. The local Cummins dealer is terrible at returning calls, but I was able to walk in and make an appointment for service/installation.

You need an "Underfloor Mounting Kit" for your genset. I think it bolts to the underside of the floor at the top of the front compartment. The genset basically hangs from the sides of it. See the appropriate section of this document: Cummins Accessory Catalog (pdf) This mount is separate from the airtight box that seals the compartment from the inside of the RV.

Hope that helps!

thanks.. I don't think the underfloor mount kit is right for this application. there is no room under floor for this genset..

usually they look like this

the box looks like this


in either case that bracket kit won't work.

my issue is that the genset weighs 290lbs, and once I get it into the box, 3.5 inches down over the lip in the front baye, I don't know how I would ever get it out if I needed to service it.

I am considering two ways to mount it, after cutting the air intake and access holes (change oil and filter) in the floor.

1. use 3.5 in square tube to set the genset on, level with the front compartment edge. (a 4x4 is the perfect size, but don't want wood in this application)
2. in addition to the 3.5, use some heavy duty drawer slides to be able to pull the unit out of the front bay. (they support 500lbs)

due to the limited room, you cannot get the enclosure off the unit with the unit still in the enclosure..

once I lift it off the front bay floor, I need to create some ducting so that the hot air from the engine fan blows out the compartment completely.

sdetweil wrote:

Stefonius wrote:

sdetweil wrote:
is your FW generator prepped?

Sadly, no. I called the manufacturer and spoke with one of their engineers. He told me that all of the generator prep is done with a specific list of parts obtained from Cummins/Onan, and sent me a copy of the list. Basically, it's a metal box put inside of the front compartment, a mount from which the genset hangs, a transfer switch, a higher flow LP regulator, LP supply lines with larger inside diameter, and a remote start switch with hour meter.

Any of the Cummins/Onan service outlets nationwide can do the installation, as they have the parts. This is the quietest and safest way to go. The unit is designed to get intake and cooling air from underneath, and the exhaust pipe runs under the compartment and opens on one side of the RV. I'll put a Genturi stack on when it's in use, so that I don't have to worry about it.

I am installing an Onan 7kw genset in my non-prepped FW as we speak. I have the floor cut template, got the box built, have run the power cord from the genset location to where the ATS will be (and power mgmt/suppressor box) (have both boxes now), just thinking thru the genset mount.. I'd love to see any info on that 'mount'.

I converted my unit to LP. and will use the Onan EC30W wireless remote start kit as it adds a set of function over the wired remote start.

edit: I have called both the local Onan office and Camping World 3 times each for estimates on the install, and they do not return call as they promise or remember that I did call before.

I got my information from the manufacturer of the fifth wheel. They gave me the Cummins part number, and I was able to look it up that way. The local Cummins dealer is terrible at returning calls, but I was able to walk in and make an appointment for service/installation.

You need an "Underfloor Mounting Kit" for your genset. I think it bolts to the underside of the floor at the top of the front compartment. The genset basically hangs from the sides of it. See the appropriate section of this document: Cummins Accessory Catalog (pdf) This mount is separate from the airtight box that seals the compartment from the inside of the RV.

Hope that helps!

MPI_Mallard wrote:
I keep my genny on a tray on the rear for my fiver strapped and locked with a cable, never had any problems and I have a short plug chord that connects my rig and I'm good to go!


Red Green:
Some men look at a problem like this and try
to find a solution. I prefer to figure out whose
fault it is and let them take care of it.

I like the way this looks and it has a place for our bikes.

I keep my genny on a tray on the rear for my fiver strapped and locked with a cable, never had any problems and I have a short plug chord that connects my rig and I'm good to go!


Red Green:
Some men look at a problem like this and try
to find a solution. I prefer to figure out whose
fault it is and let them take care of it.

Make sure the exhaust has an open area in front of it. A buddy stripped the paint off a 2" circle where his exhaust was right up against the truck bed. No major harm but always careful now to make sure which way it's pointing and there is nothing flamable in the vicinity.

I think someone else mentioned it but carbon monoxide detectors aren't that expensive. Make sure you have an operational unit.

Stefonius wrote:

sdetweil wrote:
is your FW generator prepped?

Sadly, no. I called the manufacturer and spoke with one of their engineers. He told me that all of the generator prep is done with a specific list of parts obtained from Cummins/Onan, and sent me a copy of the list. Basically, it's a metal box put inside of the front compartment, a mount from which the genset hangs, a transfer switch, a higher flow LP regulator, LP supply lines with larger inside diameter, and a remote start switch with hour meter.

Any of the Cummins/Onan service outlets nationwide can do the installation, as they have the parts. This is the quietest and safest way to go. The unit is designed to get intake and cooling air from underneath, and the exhaust pipe runs under the compartment and opens on one side of the RV. I'll put a Genturi stack on when it's in use, so that I don't have to worry about it.

I am installing an Onan 7kw genset in my non-prepped FW as we speak. I have the floor cut template, got the box built, have run the power cord from the genset location to where the ATS will be (and power mgmt/suppressor box) (have both boxes now), just thinking thru the genset mount.. I'd love to see any info on that 'mount'.

I converted my unit to LP. and will use the Onan EC30W wireless remote start kit as it adds a set of function over the wired remote start.

edit: I have called both the local Onan office and Camping World 3 times each for estimates on the install, and they do not return call as they promise or remember that I did call before.

The carbon monoxide is what concerned us the most. I hadn't thought about the heat generated by the generator. I plan to have a locking roll back cover put on our truck bed, so if I can put a generator in the truck bed and it not interfere with the fifth wheel hitch, that may be the safest option for us.

sdetweil wrote:

Stefonius wrote:
We bought an Onan Marquis Gold 5500 LP genset on Craigslist for about $1000, and will have it installed into the factory location (front compartment) of our fiver by our extremely local Cummins/Onan shop this spring. It will save us thousands over the cost of getting the unit new, and we won't have to worry about noise, theft or carrying gasoline around.

is your FW generator prepped?

Sadly, no. I called the manufacturer and spoke with one of their engineers. He told me that all of the generator prep is done with a specific list of parts obtained from Cummins/Onan, and sent me a copy of the list. Basically, it's a metal box put inside of the front compartment, a mount from which the genset hangs, a transfer switch, a higher flow LP regulator, LP supply lines with larger inside diameter, and a remote start switch with hour meter.

Any of the Cummins/Onan service outlets nationwide can do the installation, as they have the parts. This is the quietest and safest way to go. The unit is designed to get intake and cooling air from underneath, and the exhaust pipe runs under the compartment and opens on one side of the RV. I'll put a Genturi stack on when it's in use, so that I don't have to worry about it.