What kind of usage are you experiencing? I saw a guy post on the RV.net site the same exact question... Nobody answered with real world numbers... Are you getting 24hrs...36 hrs... Out of 2 bottles at full load ??
I followed his thread , but nobody seems to know, they all just post the printed facts from the paperwork...
See previous posts on ONAN / CUMMINS LP FUEL Generators for "advertised" fuel burn rates. Pay attention to altitude. It will make a difference on propane fuel usage.
You're likely asking a question that will cause many to vary their answers.
Some stay in colder climates.
Some in warmer.
Some at higher altitude.
Some on the coast.
What appliances do you regularly use?
Do you run the Refrigerator on electric or propane?
What about the water heater? Electric or propane?
Stove/Oven?
Induction stove top?
Are you a stay-at-home camper?
Or out for the day with everything off?
You can see that there are many combinations.
About the best you can hope for is the advertised rate:
ONAN 6500:
ONAN 5500:
Propane has a weight of 4.11 lbs per gallon.
If you are like us, we have (2) 40 lb tanks. That's 9.73 Gallons per tank. But, you can only fill the tank to 80%. That means there is only 7.78 gallons available per tank. Multiply X 2 = 15.57 gallons available.
If you are using the Onan 6500 and burning at 1/4 load continuously, you would have about 38.9 hours run time.
If you are using the Onan 6500 and burning at full load continuously, you would have about 12.96 hours run time.
Obviously, you could be anywhere in there or less if you are managing your fuel.
How about a heated blanket?
Have you thought about Diesel and have the spare 100 gallon diesel fuel tank on your truck? Then, you have plenty of propane for other equipment and can buy diesel at cheaper rates while on the road. You can even fill your truck when you run low.
It's not time yet, but I am still betting on the 8000W Diesel unit. It weighs an extra 120 lbs over the propane and auxiliary fuel lines have to be run from the truck. I might also have to install a small fuel pump. One thing for sure...I won't have to worry about watts...(or running low on propane and lugging those bottle around)!
