LP generators fuel consumption

Kayteg1 wrote:

Aka the breeze wrote:


Thanks , this is the type of answer I was looking for... I am on shore power 90% of the time... It's for the 2-3 times a year we go boondocking...and for the short stops during travel with the dogs...We can cool down the RV and they can stay there...so basically, we would be the same type of user...so it sounds like 28 hrs at full use out of 2 40# tanks is not out of the question...

I don't know what is your experience with RV, but I guess you have seen Prevost conversion with 5 AC on the roof?
They are there for a reason.
When you travel with your 5er in 3-digits temperatures, the interior can get into 140F range.
When you stop for lunch in no shade place and start 2 of your AC, maybe 2 hr later the interior temperature will drop below 100F, maybe not.
Even if you park in shade and manage to cool down 5er to 90F, leaving the dogs inside brings some legal restriction.
CA law for example require leaving tilted window and water, but basic common sense says you need some kind of monitoring so your dogs will not die when you drink a beer after lunch.
Some people use iPhones with camera pointed on RV floor and thermometer in view.
I will not even get into restrictions that might not allow leaving running engine unattended on public street, or parking.

Luckily we are not in CA. RV life does not have to be so complicated.
I pull up to Cracker Barrel. I get out and start A/C in 5'er. I take the dog for a walk while my family get themselves together and they go in to get a table. After walking the dog I will make sure he has food and water and put him in the fiver. He knows the drill and make himself comfortable on the doggy bed. I then go in and eat.
Thankfully, we don't have the bureau of dogs in RV's here on the east coast.
Common sense tells me the dog is not going to die in the 45 minutes it takes me to eat lunch. No cameras necessary.

Aka the breeze wrote:


Thanks , this is the type of answer I was looking for... I am on shore power 90% of the time... It's for the 2-3 times a year we go boondocking...and for the short stops during travel with the dogs...We can cool down the RV and they can stay there...so basically, we would be the same type of user...so it sounds like 28 hrs at full use out of 2 40# tanks is not out of the question...

I don't know what is your experience with RV, but I guess you have seen Prevost conversion with 5 AC on the roof?
They are there for a reason.
When you travel with your 5er in 3-digits temperatures, the interior can get into 140F range.
When you stop for lunch in no shade place and start 2 of your AC, maybe 2 hr later the interior temperature will drop below 100F, maybe not.
Even if you park in shade and manage to cool down 5er to 90F, leaving the dogs inside brings some legal restriction.
CA law for example require leaving tilted window and water, but basic common sense says you need some kind of monitoring so your dogs will not die when you drink a beer after lunch.
Some people use iPhones with camera pointed on RV floor and thermometer in view.
I will not even get into restrictions that might not allow leaving running engine unattended on public street, or parking.

Kayteg1 wrote:

What makes me really upset is that inverter technology is over 10 years old

29 years for Honda, and 18 years for the current technology! The ex300, fixed RPM and MSW output came out in 1987, 29 years ago. The ex500, with fixed RPM, sine wave output, and parallel capability hit the market in 1996, 20 years ago, and the eu9i added variable engine speed in 1998. Even Honda didn't use the inverter technology when they built RV gensets.

First of all, you will never be running at full load all the time. If you are not going to run both AC's at the same time, why go with a 5500 watt gen. A 3600 propane unit will provide 30 amps of service. It will use less fuel than the 5500. You will probably not run the gen overnight either. Too noisy right below the bed. Plus the propane you use will go a long way on park rent.

Depending on load and temperature you may not be able to draw the propane down to zero.
Need a certain amount of heat and surface area to vaporize the propane.
I am no expert but I would be carrying a third bottle to swap in if you go this route.

Lantley wrote:

Aka the breeze wrote:

Lantley wrote:

Aka the breeze wrote:
the ease of just pressing a button to start when needed sounds real nice , not to mention running booth AC's...

Not many ( if all ) real world answers here yet...

On edit... Actually , no real word answers

7 hours out of a 20# tank. My RV came standard with 4-20# tanks. For 80# total
Efficiency is not the strong point of the LP genset.
However it is great for occasional use.
The trade off in efficiency is there are no gas cans and no stale gas carb. issues to deal with. Genset is very reliable.
I am happy with mt lp Onan.
Keep in mind I am a convenience user. Lunch breaks, Wal mart overnights,
Marina Boon-docking, I do not go off the grid for long stretches. Seldom off the grids for more than 2-3 days.
If you are a heavy user to the point efficiency matters gas or diesel maybe better. But as an occasional user.
The reliability and convenience can't be beat.

Thanks , this is the type of answer I was looking for... I am on shore power 90% of the time... It's for the 2-3 times a year we go boondocking...and for the short stops during travel with the dogs...We can cool down the RV and they can stay there...so basically, we would be the same type of user...so it sounds like 28 hrs at full use out of 2 40# tanks is not out of the question...

Correct 28 hours is a reasonable expectation.
You can leave dogs in RV and go into a restaurant. Or stop for lunch and use A/C and microwave. You can do an overnight at Wal Mart or go off grid for a couple of days without issue.
You can do all of these things without making any special plans or loading up anything. Just be sure your onboard lp tanks are full and your good to go.

So 28 hours out of 4 20# tanks of propane, at 4.6 gallons per tank is 28 hours on 18.4 gallons of propane, or thereabouts.

ford truck guy wrote:
I too am looking into an Onan LP version... Wonder how many hours I can get off the 2 40# tanks with only running 1 AC ?? Less than 1/2 load....

I won't say the Onan is running full blast the whole time , But it is not smart enough to speed up and slow down to meet the load likle an inverter.
1 A/C will not increase the efficiency 50% vs. 2 A/C. My gut feeling is you will only see slightly better figures maybe an hour or 2 longer

I too am looking into an Onan LP version... Wonder how many hours I can get off the 2 40# tanks with only running 1 AC ?? Less than 1/2 load....

Kayteg1 wrote:

Lantley wrote:

Kayteg1 wrote:
Did someone shop around for new inverter generators?
Honda made top-notch use from the idea, while my 2004 3600W Generac with its inverter is pretty loud and at 1/2 load rated for 0.4 gallons of propane/hr.
Sure way better than 1+ for the above, but far cry from Honda.

The Onan is not very loud, but I imagine louder than Honda inverters. Can Honda inverters run both A/C's with just the push of a button?
It's all about the convenience a built in LP is the most convenient way to go for a large towable RV

I never run 2 AC on Honda 3000, but my AC takes 7 amps when running, so good chance is it might.
Then "convenience" is distance word. It is not convenient for me to have noise and teeth rattling vibration.
Honda 3000 has electric starter and no problem to add remote, while having it set 20' from RV you will never hear it with normal noise.
What makes me really upset is that inverter technology is over 10 years old, yet nobody can put Honda quality inside RV compartment.
Maybe like "Mexico" said in another thread - we are waiting for China to beat us to it.

Your first statement says it all"I never run 2 AC on Honda 3000".
Some/many of us need to run 2 A/C's to cool things down.
You obviously have not been around my rig with the genset running. The genset is no louder than the A/C. Keep in mind the genset is enclosed
With A/C on you cannot hear or feel genset when inside the RV.
On the outside there is not much noise either.
Inverter gensets need to be in the open to breathe and remain cool . My Onan is fine in an enclosure.

I agree inverter gensets are great for camping. I still own a Robins Subaru 4300 is genset that produces more power than the Honda's.
However there is a place for built in gensets as well.
Yes inverters gensets are efficient and quiet. But they still require set up and gas cans. Loading and unloading.
You mention setting up your genset 20' away, no need to go through any loading /unloading or positioning with a built in.
Built in is all about convenience and lots of power. I can run both A/C's and all I do is push a button. There is no teeth rattling or any of that nonsense. Onan's are not open frame contractor type gensets.
Onan's are not the solution for everyone but the built in works well for me.
Once upon a time a portable inverter genset met my needs.
Understand having choices to meet our varying needs is a good thing.
There is not a one size fits all answer when it come to gensets.
The OP appears to be a convenience user like myself. LP should work well for his needs. However if the OP was a heavy duty user efficiency maybe more critical. In which case a gas or diesel powered genset may work better.
There is no right or wrong or my way is best it is simply different strokes for different folks.
Having options is always a good thing vs. being locked into only inverter models

Aka the breeze wrote:

Lantley wrote:

Aka the breeze wrote:
the ease of just pressing a button to start when needed sounds real nice , not to mention running booth AC's...

Not many ( if all ) real world answers here yet...

On edit... Actually , no real word answers

7 hours out of a 20# tank. My RV came standard with 4-20# tanks. For 80# total
Efficiency is not the strong point of the LP genset.
However it is great for occasional use.
The trade off in efficiency is there are no gas cans and no stale gas carb. issues to deal with. Genset is very reliable.
I am happy with mt lp Onan.
Keep in mind I am a convenience user. Lunch breaks, Wal mart overnights,
Marina Boon-docking, I do not go off the grid for long stretches. Seldom off the grids for more than 2-3 days.
If you are a heavy user to the point efficiency matters gas or diesel maybe better. But as an occasional user.
The reliability and convenience can't be beat.

Thanks , this is the type of answer I was looking for... I am on shore power 90% of the time... It's for the 2-3 times a year we go boondocking...and for the short stops during travel with the dogs...We can cool down the RV and they can stay there...so basically, we would be the same type of user...so it sounds like 28 hrs at full use out of 2 40# tanks is not out of the question...

Correct 28 hours is a reasonable expectation.
You can leave dogs in RV and go into a restaurant. Or stop for lunch and use A/C and microwave. You can do an overnight at Wal Mart or go off grid for a couple of days without issue.
You can do all of these things without making any special plans or loading up anything. Just be sure your onboard lp tanks are full and your good to go.