Cost of running generator

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DickHutchings

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May 2, 2016
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219
Location
RI
I've been reading a lot about solar panels and it's making me wonder. Just how many gallons does it take to run a generator for a day. I have a ~5000w in my Winnie. I will probably test this myself but I think it will be difficult so I'll take ballpark answers.
Thanks
 
My 8500 Onan diesel uses approx .5 gal per hour at half throttle. Running the AC units is about half throttle, just charging batteries is less.  Solar is good if you do a lot of dry camping and don't need AC or microwave. Both require 120 AC and would kill a battery bank quick with much use. 

It really depends on your style of camping.
 
I can see where that would add up quickly. Thanks. I don't see any throttle control for mine. Is it automatic?
 
DickHutchings said:
I can see where that would add up quickly. Thanks. I don't see any throttle control for mine. Is it automatic?
Click to expand...

What is your make of generator?

The Hondas have a 'Ecothrottle' which senses the needed load and automatically throttles up or down accordingly.  Ecothrottle off is full throttle.
The downside is devices like the refrigerator or a/c which have a surge when when first cycling on.  It takes a second or so for the gennie to rev up and during that brief moment your a/c is demanding power your gennie cannot provide.  The a/c motor is running overloaded for a second or so until the gennie is up to speed.  In really hot weather when I know the a/c will by cycling on and off frequently I leave the ecothrottle off.  I figger it is cheaper to buy gas than replace the a/c motor.
 
I have a Honda EU 3000 and I purchased a 50 straight blade to a 30 amp twist lock and it will plug into the EU 3000. I live in Central Florida and last weekend when I was plugged into the Generator I had my Frig which is all electric 2-TV's, 1-13,500 AC and the Inverter/Charger on. I had to take the Generator off the Econo Mode so that the voltage did not drop very low because of the AC starting up. I think the Generator holds 3.8 gallons of fuel and it lasted 13 hrs.' over night.

Herbie
 
I think you need to look at more than just fuel costs. :-\
1. If a generator was running all day, much of that time would be idling when nothing is running.  This is not got for generators--at least that is what I have always been told.
2. In addition this would require weekly oil changes.  Basing that off of my ONAN 400 microquiet where I think it is recommended to change the oil every 100 hours.
3. Depending on how often one did this, I could see a generator not lasting very many tears?
 
More issues pop up with gen sets from lack of use than wearing them out. Doing an oil change is an easy 30 minute job on most generators, especially after you do it a couple of times.
 
DickHutchings said:
I can see where that would add up quickly. Thanks. I don't see any throttle control for mine. Is it automatic?
Click to expand...

Automatic... Explanation follows.

There are two types of generators (Well two main, couple of sub types) Inverter Generators, are usually portable and usually have model numbers ending in a lower case "i". are fairly expensive but you will hear the motor speed up and slow down as the load changes

Most RV generators are what I call Traditional generators, they run at 3600/N RPM where N is an ingiger (usually 1,2 or 3) so they run at a constant speed  3600 RMP, 1800 RPM or 1200 RPM  Note that the lower speed types are usually more expensive, and much higher quality... Again USUALLY, just like above no guarantees anywhere (My 1800 RPM Onan is one dang fine generator)

In order to either maintain the engine speed (Traditional Generator) OR increase it (Inverter model) it is necessary for the throttle to open.. So they have automatic devices of one kind or another to do just that.

Some sense the current flowing and use it to control, all or in part the throttle,  These are very good.. Some do it with computer control of the engine speed.. But all have a throttle, and on a generator it is always automatic.
 
Gas is pretty cheap right now, wait until it goes back to $4.50 a gallon and solar starts to look really nice. With solar the trips to the gas station are fairly rare.



The information is out there, all you have to do is let it in.
 
Fuel consumption is largely a matter of the electrical load and folks are kidding themselves if they think a Honda portable is any less expensive to operate when producing 2000 or 3000 watts than a big Onan 7500 diesel. There is no free lunch.  Where the small portables help is when there is no load or very low load on an inverter-type genset. It can and does throttle way back, reducing both noise and idle fuel consumption. Still not a bunch less than a larger inverter genset, but definitely less than a larger "traditional" constant rpm genset (see Detroit John's message). And the portable of the constant rpm "traditional" type have no advantage at all.
 
Jeff said:
More issues pop up with gen sets from lack of use than wearing them out.
Click to expand...

Do you mean lack of use--sitting not running?
OR
Lack of use, idling, not being under load?
 
Lack of use sitting.  When you don't use the generator, it's windings collect moisture, tarnish accumulates on the slip rings that transmit power to the excitation coils in the armature, water collects in the engine oil from condensation, fuel sits and decomposes into gum and varnish in the carburetor leading to starting and running problems.

Starting and running the generator once a month will prevent most of these problems.  Running it under load for about an hour will heat up the windings and oil, driving accumulated moisture out of them.
 
Solar vs generator:

My outlets don't work when I'm on battery power, only when I'm plugged into shore power.  If I bought solar panels, would I be running off battery power or would the trailer think I was on shore power?

the only thing that keeps me from dry camping is not having my outlets available to me.
 
You would have to install an inverter to provide 120vac power, whether to all outlets are just some specific ones. Solar panels produce 12v power and basically are battery chargers. They are not a substitute for shore power with out also using an inverter.
 
I realize they require an inverter to provide the correct voltage.  I'm really wondering is that all I have to do to get my outlets to work?  Is there some kind of switch or sensor that keeps them from working, or do they not realize/care if I'm on shore power or not as long as 120 vac is present?
 
The AC receptacles are on an entirely different circuit than the batteries/DC. So, no switching needed.
 
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