Gas usage per hour with a 5kw Rv Generac generator

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StephenM

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Evening all,

Just back from first dry camping trip. I really enjoyed it.
My wife was asking me how much gas does the generator use.

I have a 5kw generac from 2005.

I am wondering how much gas it uses in the 3 below scenarios. My lighting is Led and the fridge is lp, water pump would be running intermittently. A microwave, kettle or toaster may be used for short time also.

1. Just charging batteries.
2. Running a 1200watt oil storage heater and LP furnace.
3. Running a 13500btu air conditioner.

Thanks,

Stephen


 
Generac rates the Q55G (gas) generator at .21 GPH at no load, .48 GPH at half load, .62 GPH at 3/4 load and .83 GPH at full load.

https://generator-parts.com/manuals/generac-rv/091355.pdf

Figure your battery charging, lights, TV, etc. will barely load the generator, so it'll use about just over the no-load amount, or about 1/4 gallon per hour.

The air conditioner or the heater use about a 10-15 amps each, so running one or the other will make the generator run at about half of it's rated load and will use somewhere around 1/2 gallon per hour.  Theoretically you won't have both on at the same time.

The Generac generator is slightly more efficient than other similarly sized gas generators because the belt drive doesn't make the engine run at 3600 RPM like it would if the engine was directly coupled to the generator.  Instead, the engine runs at 2500 RPM, which is a more efficient speed, and the belt drive increases that to the 3600 RPM the generator needs.

This assumes your generator is in good tune, changing the air filter and performing the other maintenance as scheduled.  An engine that is neglected or out of tune will use more fuel.
 
Read the manual.

My 4kw manual claims to use 0.5 gallon per hour at full load.

I really have no way to test this since it draws on the same tank as the engine. I am in a Class C with no car, so I drive a few times a month too.
 
Let's think. Of it this way.    The gas. To run you generator even 24/7 on a camping trip is still way less then sight fees..... I use a 3500 generator.  And use 11gal of Gan on a weekend running the ac Friday and Saturday night.    When I don't need the ac.  I will use 2 to 3 galans charging battery's and using 110 appliances
 
StephenM said:
Evening all,

Just back from first dry camping trip. I really enjoyed it.
My wife was asking me how much gas does the generator use.
Thanks,

Stephen

Hmmm, your wife asked..... The generator should be plumbed from the vehicle gas tank so that it will not run the tank dry, stranding you in the Boonies. This should reassure her!
 
I had told her the generator would cut out a 1/4 tank.

I will read the manual.

 
As a rule of thumb, most small gensets use about 0.5 gal/hour at 50% load. That number works reasonably well for gensets in the 2-8 kw range. 50% load means half the max sustained wattage rating, e.g. 2500 watts from a 5000 watt (5 kw) genset.

A fallout of that is that an 8 kw genset producing 2kw uses about the same amount of fuel as a 2kw genset  running at its full 2 kw output. There is no free lunch - a certain amount of fuel must be burned to produce a certain amount of electrical energy. Differences in efficiency are small across that range of genset sizes, so a "big" genset doesn't use much more fuel than a smaller one. Often the fuel consumption per actual kilowatt used is near identical. This is especially true of larger inverter-type gensets that are very efficient across a range of wattage output.
 
Cheers Gary,

That's Genset is big to me as my backup one at home is only 3500.

My buddy had a Honda invertor generator with him and that was really nice.

 
Was at the storage and had a look at the manual. It is indeed the Primepact 50. Half load is .46 and full load .76.
 

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