why generators need to run under load

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winona said:
Thanks for the link to the manual  --- read the parts that pertained to mine.  And now I'm trying to figure out what to run that fulfills the 50% to 70% load for time frame.  Can't make that much coffee nor run a hair dryer that long.  :D  So the air conditioner when it's already 20 degrees this winter?

My generator is gas, and I've added Stabil and run the engine and generator for while, hopefully to get it where it needs to be.

Sometimes this tryin' to do right for my rv makes my brow wrinkle.....
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I don't think 50%-70% is absolutely necessary, just a significant load. Maybe turning on the water heater, holding tank warmers(as long as there's a few gallons or more in them) and fridge would be enough (if it's not cold enough to run air conditioner).
Also, the coffee maker uses a good load when on without brewing coffee, just be sure there's sufficient  water in the carafe as to not overheat the glass.
Just my opinion.
 
skydivemark said:
I don't think 50%-70% is absolutely necessary, just a significant load. Maybe turning on the water heater, holding tank warmers(as long as there's a few gallons or more in them) and fridge would be enough (if it's not cold enough to run air conditioner).
Also, the coffee maker uses a good load when on without brewing coffee, just be sure there's sufficient  water in the carafe as to not overheat the glass.
Just my opinion.
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The water heater is drained in the winter, so that's out. My tank heaters are 12 volts, so that won't work. Refrigerator is only a couple of amps.

I'll stick with the space heaters.
 
I have run the block heater, both AC units and turned on the Convection oven to pre heat. I think I was at about 42 amps.
I would run over 50% load as a minimum. It is pretty easy to do and will save you money in the long run.
Bill
 
I feel the 50%-70% load is an engineers ideal "wish list", as is the 2 hour run time and every 4 week interval.  Undoubtedly "goodness", but well beyond a minimum requirement.  I notice they give an example of one a/c unit on a 4000W genset, yet one a/c is about a 1400 watt load, not the 2000-2800 that the percentage would suggest.  1400/4000 is only about 35%.  I think you can take some liberties, as long as you actually do it. Similarly, 30-40 minutes is probably adequate in all but the dampest climates and 6 weeks instead of 4 isn't going to be a killer either.

The 4 week interval is driven primarily by the potential for gasoline evaporation is warm, dry climates.  Diesels can go longer between exercises, since they have no carburetor to worry about and the fuel evaporates slowly as well. Moisture is the primary concern with diesel gensets, and northern winters and western climates in general are dry enough that moisture build-up is slow. Spring and fall, however, often have the warm/cold cycles that produce a lot of condensation in machinery of all kinds.

For what it's worth, Onan used to recommend 50% load for 30-45 minutes.

With my Onan QD 7500, I would run one or both heat pumps (1400 watts each) for about 45 minutes a couple times each winter in Florida. That's about a 33% load. Space heaters work well to, at 1500 watts each.
 
With some of our storms here in Northwest Indiana, I like the thought of being able to run a cord from Winona to power a lamp or something in the house when I lose electricity.  One year I shoveled a path through the snow to the outlet and ran the cord into the house.

Mine is winterized so nothing is in the tanks nor water heater.  Suppose I could always pop my popcorn out there?

Thanks, and I have appreciated all the input!
 
During Irene and Sandy, the motorhome became our source of power and refrigeration for several days. It's nice to have it sitting out in the driveway.
 
On a diesel generator you need to run at half load or more to keep the carbon from collecting on the pistons, head and valves.  Back before I knew this I used to run our diesel generator on our sailboat about 3 or 4 hours a day with only the battery charger as a load which was probably a 5% load.  After a couple of years of this practice the generator refused to run.  After about $1500 to remove the head, clean and de-coke the head, valves and exhaust manifolds, the diesel mechanic told me to run a load on the engine when charging.  After that I would air-condition or heat the great outdoors to load the engine and had no further problems.


When I graduated to RVing I always would always put a load on the generator when running the monthly runs or when camping.
 
The other reason to run the generator under load besides warming up the oil and windings is that most engines at idle move very little fuel, so if the fuel system is compromised it may not be noticed. By loading them up you move more fuel through the system and will know if you have a fuel system issue.
 
I try to run mine between campgrounds once a year.

Space heaters.. I do not like plugging space heaters into Standard RV type Quick-Box or Speed-Box outlets.. They tend to give my noise a sence of Overheated Romex.. That is an aroma that frightens me as it were because it is often followed by a "Company" that makes house calls.. A Fire company.

(Political question, DO NOT ANSWER THIS, Why are a group of firefighters called a Company?)

I have special heavy duty outlets (12 ga wire wrapped around a properly tightened screw) in 3 places.. No problem with those outlets.

During and following Hurricane Matthew My Generator got a good workout  (2 RVs)  And a couple of weeks ago I was preped to use it.. but wound up only running on battery power for a few hours.
 
HappyWanderer said:
The water heater is drained in the winter, so that's out. My tank heaters are 12 volts, so that won't work. Refrigerator is only a couple of amps.

I'll stick with the space heaters.
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OOPS For  missing the part about freezing winter weather, I'm in FLA so freezing weather isn't something I pay a lot of attention to.
 
I would like to know if you need to unplug from shore power when you run your generator to exercise it?
 
Oh, side note.. In another forum there is a topic titled "Believe what they say" written by a man who ignored the advice to exercise his generatort....... and paid the price when it neeeded major repair.
 
The Generac generator that's in our trailer is the third trailer it has been in, we bought it 1998 and I have never test run it under load and test runs only happened every few months when it sitting still if I remember to do it. It has never failed us yet except for a very bad load of fuel we got in California.

Denny
 
rvpuller said:
The Generac generator that's in our trailer is the third trailer it has been in, we bought it 1998 and I have never test run it under load and test runs only happened every few months when it sitting still if I remember to do it. It has never failed us yet except for a very bad load of fuel we got in California.

Denny
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Yes you can get buy not doing the recommended maintence right up to where it quits and gets expensive.
Bill
 
WILDEBILL308 said:
Yes you can get buy not doing the recommended maintence right up to where it quits and gets expensive.
Bill
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If it dies after 19 years I would consider it normal life expectancy not because I didn't test it under load.

Denny
 
Yes Denny, you can do that. However we were trying to help the OP with the best practices for his generator based on Onan recommendations and recognized industry guidelines.
Let me wish all a wonderful Thanksgiving.
Bill
 
NY_Dutch said:
I've seen well maintained Onan generators still running that are much older than that...
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Mine still runs as good as it did in 1998 so I'm planning on many more years.

To the OP if your rig is stored for the winter I wouldn't try and run it because you will just be asking for more condensation build up when it cools down in cold weather. If it was running good when you winterized it wait till spring.

Denny
 
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