5.5 or 6.5 Onan

[ted 95]

Need some input. I'm going to add an Onan to a 2015 GK. The unit has 2-ACs with heat pump/ residential fridge / induction cook top / fireplace / dishwasher / washer - dryer. These are the big electricity consumers. Does anyone out there have a 5.5 and feels at times it just is not keeping up when you are in a full demand load. Onan of Elkahrt suggests any coach over 36' needs a 6.5 and especially a unit that is classified as a full time unit. The different in cost is about $880-$1000 more. They are the same size and the same weight. the only difference is the consumption of gas. Any input would be a help as I want to do it wright the first time.
Here is a second part. Seeing as the truck is a diesel would you install an LP or Diesel. And run a connection from the truck.
Thanks

[gford10480]

Personally, I'd go with the 6.5. I have the 5.5 LP version and it will trip a generator breaker when both A/Cs kick in at the same time, but otherwise the 5.5 does fine.

If you are traveling, how would you get the diesel supply? I would think the only choice for a non-toy hauler is LP. I did switch my 30# LPs to 40# cylinders, LP does go fast. (I miss my toy-hauler with the 60 gallons of gas for my old Onan 5.5 gas generator. But at least you won't have to worry about stale fuel with the LP)

[Dave&Ginny]

I had the 5.5 and it did everything I needed it to do. With that said.....if you could run a diesel generator in the bed of your truck (off the trucks fuel tank), I think that could be a very effective setup. That way you wouldn't have to contend with the LP and the diesel fuel wouldn't get stale from lack of use.

[bergeman]

I haven't added a generator yet. But I am in the process of adding an auxiliary fuel tank to the truck. I will have almost 90 gallons. My plan then is to get a diesel generator, ether portable or in the RW.

I much rather have to find diesel then LP. From what I read on these posts, the generator goes through the LP quickly.

One more thought, before I get the generator, I am trying to decide if I spend the same amount of money on batteries and solar if that would be a better option. Knowing full well that I wouldn't be able to run the AC's on that set up. But then, most nights in many areas get cool enough.

Lithium batteries are starting to come down in price. So may questions.

[gford10480]

Just as an fyi, there is apparently an option on the Onan generators to have 30/30 Amp breakers; mine are 30/20 and the 20 amp is the one that throws when both A/Cs start up at the same time; but I have learned to wait for a few minutes before turning the other one on.

[bull_chips]

My rig was pre wired for a generator and I had the dealer install the Onan when I made the original purchase. They said the factory would only allow the installation the 5.5 LP. It works fine. I don't have a washer/dryer but everything else and use the generator often when we stop for lunch. Never a problem.

[piper guy]

Onan makes a 6500 Diesel generator that is the same size and footprint as the gas ones. It is around $7.4 k depending on source and is actually quite ran the gas one.
If I go to a gen set it will be either this one or one mounted in the truck with an umbilical cord to the coach. There is more than enough room to build a mount and put a 15-20 gal diesel tank above the gen.

[mhs4771]

We have the 5.5 with the 30/30 breakers and have run both ACs without a problem. You have to really look at your big loads and guess how many you would ever have running at the same time.

[KevinSonya Harmon]

We have the 5.5 and last week during PDI, I turned on everything I could to test the generator capacity. Granted the weather wasn't overly warm, but the generator ran everything both A/C's, fireplace, microwave, every light, TV's plus moved the slides in and out. Assuming you turn the A/C's on independently, you shouldn't have a problem with the 5.5. The LP version is surprising quiet, not sure about the DB rating on the diesel version.

[5th_Time]

Ugh, picture how loud an Onan generator is in the bed of a truck with no exhaust - even with one! You need a generator when you can't plug in... like boondocking in state parks or beach campgrounds. Doesn't "sound" practical.
When Redwood OEMs only the LP version, that tells you something...

[atom ant]

Originally Posted by gford10480

Just as an fyi, there is apparently an option on the Onan generators to have 30/30 Amp breakers; mine are 30/20 and the 20 amp is the one that throws when both A/Cs start up at the same time; but I have learned to wait for a few minutes before turning the other one on.

gford, try swapping the 20 and 30 circuits in the transfer panel. I have the 30/20 version and it has done fine running both ACs, as long as I shut off the HW tank electric, however when I first installed it in my Montana it initially would pop the 20 side. I had to rearrange some circuits on the bus, as they had both ACs on one side.

[bergeman]

Has anyone had any experience with Generac RV generators. Same style as Onan but half the price. I'm seeing a new diesel or or LP, 7500 watts under $3k.
Generac RV Generators

That's less then half the price of Onan.

[Blue Dogs]

Originally Posted by bergeman

Has anyone had any experience with Generac RV generators. Same style as Onan but half the price. I'm seeing a new diesel or or LP, 7500 watts under $3k.
Generac RV Generators

That's less then half the price of Onan.

Had one in a camper, it was a 3K watt LPG ... if it was anything like the larger ones ... Run don't walk away! It was very difficult to keep running and super hard to find service for. FWIW, I will never own another.

[dieseldave]

Originally Posted by Blue Dogs

Had one in a camper, it was a 3K watt LPG ... if it was anything like the larger ones ... Run don't walk away! It was very difficult to keep running and super hard to find service for. FWIW, I will never own another.

I had the 7500 model in my last 5th wheel and had the same issues. Generac actually stopped making rv generators a couple of years back.

[RCAircraft]

Originally Posted by ted 95

Need some input. I'm going to add an Onan to a 2015 GK. The unit has 2-ACs with heat pump/ residential fridge / induction cook top / fireplace / dishwasher / washer - dryer. These are the big electricity consumers. Does anyone out there have a 5.5 and feels at times it just is not keeping up when you are in a full demand load. Onan of Elkahrt suggests any coach over 36' needs a 6.5 and especially a unit that is classified as a full time unit. The different in cost is about $880-$1000 more. They are the same size and the same weight. the only difference is the consumption of gas. Any input would be a help as I want to do it wright the first time.
Here is a second part. Seeing as the truck is a diesel would you install an LP or Diesel. And run a connection from the truck.
Thanks

Doing the math on my rig, and applying the 80% rule I selected the 6.5 KW Onan Gold propane fueled which has a similar KW load as your RW. It's best to not fully load a gen set due to variables including high ambient temperatures.

[nwirt74@gmail.com]

I have a question for you sir? I am getting ready to purchase the 5.5 pretty quickly. My 13 36RE came with the factory prep for the generator, It has a wiring harness in the gen. compartment and the hour meter and start/stop inside the coach. Other than run the power cable to the battery and the fuel supply and the exhaust what else is there as far as installing myself? Any help would be greatly appreciated!!!

[ted 95]

When i had mine installed at Onan in Elkhart they also installed an exhaust scoop / deflector. When i asked them what and why as i had never seen that on a rig before. the explanation was --
very often a gen will shut down for what you think is no reason on a hot summer day. the problem is the intake is sucking in the hot exhaust air and causing the gen to over with out the deflector. with the deflector it shoots the air to the road side.
and even more important you can cause a grass fire with the hot exhaust going straight down.
ive trried to post pics and just can't figure out how. if you pm me iwill send you a pic of the scoop.
also be sure your muffler pipe is no where near a window or opening to the unit.

[atom ant]

Originally Posted by nwirt74@gmail.com

I have a question for you sir? I am getting ready to purchase the 5.5 pretty quickly. My 13 36RE came with the factory prep for the generator, It has a wiring harness in the gen. compartment and the hour meter and start/stop inside the coach. Other than run the power cable to the battery and the fuel supply and the exhaust what else is there as far as installing myself? Any help would be greatly appreciated!!!

You didn't mention the output power cable to the transfer switch. Other than that, I think you covered it. The exhaust is a real pain in the keester finding the right parts, as the local exhaust shops don't go as small as 1". It pretty much needs to be a kit from Onan or Redwood to get it to come out between the slides.

Teds air scoop sounds interesting. I didn't have it but I do know someone with the 6500 that had to do that because of overheat, especially with the Z-frame Redwood having the generator so close to the ground.

[Ford truck guy]

I also am very interested,,,, PM sent

[Ford truck guy]

Thanks for the email.... here are the pics - so it looks like it dumps the hot air to the street side of the trailer... I what are the dimensions?