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Old 08-11-2022, 03:37 PM   #1
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How much gas…

First time boondocking. We have a gas generator, 4000 watts, and a 15,000 btu A/C unit, any idea how much gas it uses per hour?

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Old 08-11-2022, 03:40 PM   #2
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If on the AC is running, I would say about .8 gallon per hour.
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Old 08-11-2022, 08:04 PM   #3
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Our Onan gold, uses about .4 an hour with 2 13,000 units running..
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Old 08-12-2022, 05:00 AM   #4
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Top off your tank before you park.
And remember the gen will stop running at approximately 1/4 tank.

If you want to know your generator burn rate...keep track of the hours the gen runs. Then top your tank again right after you pack up and leave the boondock.
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Old 08-13-2022, 12:18 AM   #5
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Pretty sure onan provides estimated fuel burn based on percentage of load for all models.
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Old 08-13-2022, 03:47 PM   #6
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Yo have to remember, that if the generator is running , then it is running everything in there, not just the AC.
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Old 08-13-2022, 04:41 PM   #7
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Originally Posted by PJStough View Post
If on the AC is running, I would say about .8 gallon per hour.

This is a pretty good estimate,
Granted ours 3500 on our last trip ours averaged .7-.8 per hour with the ac running.
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Old 08-13-2022, 05:14 PM   #8
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As a rule of thumb, Onan's use about 0.5 gal/hr at 50% load. A bit more for the larger ones, a bit less for the smallest sizes, but that's a pretty solid guestimate. A late model 15,000 btu a/c uses about 1200 watts, which is 1200/4000 (30%) of the generators full load capacity. That works out to be about 0.3 gal/hr for the a/c alone, but it's never alone. Your converter/charger runs whenever the genset is running, and the fridge auto-switches to electric mode too, so a good estimate would be about 0.4 gal/hr.
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Old 08-14-2022, 10:58 AM   #9
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Originally Posted by hedhunter9 View Post
Our Onan gold, uses about .4 an hour with 2 13,000 units running..
I believe I would have kept that unit! Our 5.5 uses .9 at full load.
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Old 08-14-2022, 02:55 PM   #10
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What is the fuel usage that the owner's manual shows for your generator.?

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Old 08-14-2022, 09:58 PM   #11
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Plan for 3/4 gallon per hour of use.
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Old 08-14-2022, 10:29 PM   #12
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It’s been awhile but I seem to recall about 1/2 a gallon per hour with one AC and the fridge etc.
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