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Old 04-06-2017, 09:45 PM   #1
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Onan 5500 generator install qustions

I'm planning on installing an Onan 5500 in our new 3950. The questions I have:
1- does the factory reinforce the floor of the front bay?
2- does the generator sit in risers so it is more serviceable?
3- debating yet between gas or Lp, any body installed a gas unit? Where did you install gas tank? I realize LP unit is a simpler option, but would like gas due to refilling and availability of gas anywhere .
4- is the sheet sheet metal surround like the factory does needed?
5- has anybody used the tri fuel conversion from US Carburetion?

I had a gas unit in my previous toy hauler, I know some will suggest a portable genny, but have decided I want it on board!

Pictures would be great!

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Old 04-27-2017, 11:19 PM   #2
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I'm interested in doing the same thing. I'm guessing with the lack of responses that most folks go the portable gen set route vs. the Onan 5.5 install.
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Old 04-28-2017, 12:54 AM   #3
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I had an Onan 5500 Genset installed at time of purchase last year. Most of my response are in general form to what you are asking. The dealer prepped it for $1000 and the Genset was $5700. They encased it with sheet metal and wired the system to my In-Command digital panel and a 2nd battery. The gen's casing is really the soundproofing and the sheet metal is for isolation purposes. I preferred LP fuel, as this is based on the motorhome that I had previously. The propane is quite adequate for 1 to 2 hour uses and my 2 bottles can be taken out and filled up at most places. Also, I don't have to deal with carrying additional flammable liquids in my units.

This was probably an unnecessary accessory for my type of activity, plus the extra 200 plus pounds on the front of the trailer. I've used it for about 5 hours in a years time and that's mostly for periodical function checks. As I mentioned, it was great thing for a midsize motorhome to do spontaneous stops overnight at Walmart or casino parking. The 5th wheel is more for direct destinations and Campgrounds. My unit is in the storage lot and won't have pictures for awhile. One more thing, it does impact the amount of storage space for a model 3820 which has only 3 x 4 thru cargo area.
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Old 04-28-2017, 06:29 AM   #4
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Combine what FreeRoamn and Dusters said and you'll understand why the majority of folks opt for an external one. We did have two Yamaha inverter generators that could be ganged for 30 amp service - enough to run the 15k AC unit easily. I sold them when I added solar and four T-105s, but ended up getting a HF unit for the occasional overnight when it was really hot. (It's actually not much louder than the two Yamahas and runs considerably longer.) Any external one won't be as convenient as an internal, but they are vastly less expensive.
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Old 04-28-2017, 07:25 AM   #5
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All four of my campers have had onboard generators and all of them LP. I ordered 3 of the 4 with the prep pack for the genny, the TH TT came with it. I've only had one genny though. I've always paid my dealer to move it from one to the other each time we bought a new camper. The main reason I wanted a genny onboard is our son has asthma and I have always made sure I had alternate power available if our power at home was out. That being said, we've been through a tornado that destroyed half of the park and we used our genny to power lights and tools in the surrounding area. As well as used it for the rescue teams to take a break in. I'm a 30 year paramedic myself and am always planning for alternatives. I've always had LP on the 5ers due to it being much easier to use, store and the genny's carburetor doesn't get clogged up after sitting a bit. The TT I have has a 37 gallon fuel tank on it separately. I've never wanted to put gas on my 5er as my FIL did this on his and the basement area always has a hint of gas fumes.
It does take up room, but that is ok with me. It alleviates having to load another and take it just in case, eliminates possible theft and frees up the bed of the truck while traveling.
Just my .02 cents....
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Old 04-28-2017, 08:00 AM   #6
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We have the built in Onan on our last two Montana's. We also have the remote control module installed which allows me to start and stop the genny while in transit. We use the genny for cool-down and cooking when travelling as we eat meals in the rig at rest stops rather than try to find suitable eateries. As mentioned, having been subjected to power failures at various parks, we like to have the backup power available. To answer your specific questions, your rig should have the proper floor already installed in the generator compartment, and from my understanding the generator bolts directly to the floor. The metal surround is needed for insulation as well as sound buffering. We prefer LP from a safety aspect but have elected to swap the original 30# tanks out for 40# tanks. I have portables and arrived at the point that I did not want to undergo the physical exertion that they required for each trip. In addition, our rig is stored at a mini-storage facility, and if I need power at the mini-storage, all I have to do is fire up the genny and we are good to go. Good Luck with your decision!

Bingo and Cathy - Our adventures begin in the hills of WV. We are blessed by our 2014 3850FL Big Sky (previous 2011 3750FL and 2007 3400RL) that we pull with a 2007 Chevy Silverado Classic DRW CC dually.
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Old 04-28-2017, 11:27 AM   #7
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On my unit the floor "floor" is not reinforced and I don't see any reason for it just MHO.

The genset sits on a riser block secured to the metal deck of the front compartment.

The sheet metal shroud fulfills the fire rated wall requirement.

I would only have gone with gas if I had the ability to install a gas tank permanently on the vehicle. That will be the plan with SOB in the future.
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