Community Forums

Nomad_Haabs · 12-20-2020, 08:47 PM

We are looking at purchasing either the Montana 3855BR or solitude 378 MBS-R. We want to have the Onan generator installed, but how do you know what size is required for your RV?

okcnewbie · 12-20-2020, 09:30 PM

From what I've seen anything with more than one Air Conditioner needs more than 4k.
It's really math though. Just plug in what you're going to use and sees if there's a buffer or not.

NewBlackDak · 12-20-2020, 09:38 PM

If you have multiple ACs, just get the 5500.

Nomad_Haabs · 12-20-2020, 10:26 PM

With a 5500 how long can we realistically expect to be able to boondock with it? Is it quiet?

twinboat · 12-21-2020, 05:51 AM

The 5500 generator in my old MH was quieter then my 4000 in my new MH.

The 5500 ran at a lower RPM and that made it quieter. They use belt drive to run the generator head at 3600 RPM from a lower, 2400 RPM engine.

The 4000 generator is direct drive and the engine runs at 3600 RPMs.

The 5500 burns .9 gallons an hour at full load, about .5 gallons per hour at half load.

I never hear the generator when the AC is running and I like my AC.

KanzKran · 12-21-2020, 06:10 AM

Quote:

Originally Posted by Nomad_Haabs

With a 5500 how long can we realistically expect to be able to boondock with it? Is it quiet?

According to the specs, that Keystone has a 14.2 gallon propane tank, and the 5500 burns 1.1 gal/hr at full load, and 0.8 gal/hr at half load. That’s a theoretical 12.9 hr at full load and 17.8 hr at half load.

The Solitude appears to have the same LP capacity.

Edit: I should add that I don’t know if that 14.2 gallons is water capacity (filled to the top, which is what’s usually stamped on ASME tank data plates), or if it’s net capacity at 80% full, which is the max you can legally fill them. 14.2 gallons is 60 lb of propane, so it could be net capacity.

My tank label. 12.2 gal is water capacity; it’s only good for 9.8 gal usable, or 42 lb of propane.

MtCamper · 12-21-2020, 06:51 AM

In a motorhome a fuel matched generator makes good sense. In a towable, I don't think it is your best option. On board generators will use propane unless you fabricate your own. Propane won't last long if you boondock and run your A/C. On board generators take up a lot of valuable storage space and are expensive. I suggest you consider a separate gasoline 5500w generator in your truck bed in front of the hitch. Not as easy to use and can't be used when your truck is gone but way cheaper and much easier to fuel. As for noise, a truck mount will probably be louder when you are outside, but we can't hear ours when inside with the A/C on.

LETMGROW · 12-21-2020, 07:53 AM

The size of your generator will depend on what you are running for equipment in your RV. 5500 W. will do for most folks but if you have a residential refrigerator, an electric water heater, two or more AC units, multiple TV sets, a washer and dryer and microwave you would have to be careful how many appliances you run at the same time. The above list is just an example. You should list everything you may want to run at one time and add up the wattage you would require. Don't forget to check the draw on your inverter.
If the wattage isn't listed on an item you can find the amperage draw and multiply it X 120(V) to find the wattage. You will be surprised how quickly this adds up.

robertkathy · 12-21-2020, 09:03 AM

if you have a washer/dyer you need 7000watt to run the washer 7500 watt for the dryer. i know this cause my gen is only 7000 watt and i can not dry only wash.

**hamm2018** · 12-21-2020, 10:08 AM

Quote:

Originally Posted by Nomad_Haabs

We are looking at purchasing either the Montana 3855BR or solitude 378 MBS-R. We want to have the Onan generator installed, but how do you know what size is required for your RV?

We have a 2018 Road Warrior Toy Hauler, with the 5500 Onan factory installed. The Power Management System shows the 5500 output is 45 amps. With the available power during the genset test every month I run 2 AC and some other equipment to get my load. Since we have a toy hauler our Onan is a gas model, and it does a great job, the noise level is not bad at all.
The 5500 Onan should be really good for your application.

okcnewbie · 12-21-2020, 11:25 AM

Quote:

Originally Posted by robertkathy

if you have a washer/dyer you need 7000watt to run the washer 7500 watt for the dryer. i know this cause my gen is only 7000 watt and i can not dry only wash.

Something doesn't sound right about this to me. The splendide dryer spec only calls for 12amps. How many amps is your dryer pulling?

consolenut · 12-27-2020, 06:29 AM

I run a 12.5kw onan. Works great Can run everything and anything i want. Yeah something dont sound right cant run dryer on a 7500. thats 31 amps per leg 220. should be plenty. unless you have an AC or water heater on electric same leg as the dryer.

okcnewbie · 12-27-2020, 07:53 PM

Quote:

Originally Posted by robertkathy

if you have a washer/dyer you need 7000watt to run the washer 7500 watt for the dryer. i know this cause my gen is only 7000 watt and i can not dry only wash.

Don't want to hijack but this could be applicable to OP.
Presumably your dryer works on shore power.
What exactly happens when running on the Gen?
Just trying to get to the bottom of it. Seems you should be fine on that 7k gen