Generator Exercise Question

[DCMAC214]

(didn't see answer in 3 pages of search)

How much of a load should I put on the generator to exercise it?

E.g., what and how many lights, appliances, etc.?

[bigb56]

Originally Posted by DCMAC214

(didn't see answer in 3 pages of search)

How much of a load should I put on the generator to exercise it?

E.g., what and how many lights, appliances, etc.?

My Cummins Onan diesel inverter generator says 50% load for 2 hours each month. I think it's a little overkill for me since I live in the desert, store it indoors and the inverter has no slip rings to rust.

What kind is yours? If gasoline powered exercising might be more critical.

[Cajun 143]

I run mine 1 / month.
Run ac for 1 to 2 hrs

[wildtoad]

Run AC for an hour in summer while running generator. In winter, run 1500 watt electric heater. If you have a heat pump, run that.

[boomersooner]

I run the gennie every 30 days, minimum one hour, and run either AC or heat pump depending on temperature. This is done on my 30-40 mile drive that I do monthly if I am not on a trip.

[Gary RVRoamer]

Used to be the genset manufacturers suggested 30 minutes at 25%-50% load, but in the last few years the the duration keeps going up. Now Onan says 2 hours at 50% load every 30 days. 50% load means half the rated watt capacity, so 2500 watts for a 5000W genset, and so on. That would be two roof a/c or heat pumps in constant operation, or a water heater in electric mode + one a/c, etc. But remember, those things cycle on/off at all the time.


As a general rule, gas generators need more frequent exercise than diesels and alternator generators more than inverters. That's because of some fundamental design differences. And damp climates more exercise than dry ones.


From the Onan Generator Handbook


EXERCISING YOUR GENERATOR
It may seem surprising that not using your generator could cause
performance problems, but with RV generators that’s exactly the case
Regular “exercise” is a very important part of keeping your generator
healthy Lack of exercise can cause moisture buildup and fuel system
degradation that will make it run poorly In fact, in as little as 30 days, the
fuel in gasoline-powered generators can begin to gum and varnish the fuel
system Fuel varnishing results in hard starting and surging (A surging
generator never settles at a stable operating speed )
To prevent such problems, it is recommended to run gasoline generators at
a minimum of 50 percent capacity (2,000 watts, or one air conditioner for a
4,000-watt set) for two hours once every month This is necessary to help
keep moving parts lubricated, expel moisture and control fuel varnishing
in the carburetor A continuous two-hour exercise period is preferable to
several short periods While traveling, this can be accomplished by running
the air conditioning If you own an LP or diesel generator, regular exercising
can help reduce internal condensation and helps keep seals lubricated
Remember to exercise, not just start and run your generator.

[Alpine36]

I run ours about one hour a month at about half load.
Coincidentally our rather noisy neighborhood well house backup generator does a test run once a month. That’s my reminder.

[DCMAC214]

Thanks all!

[Tony Ramirez]

Not only for the fuel system, but I think I read oxidation w develop on the stator & rotor. That's another reason for the monthly exercise. Am I mistaken?

[chopity]

Cold and humid maybe every month.
Dry and hot climate can go longer.
For gasoline guys makes sure to open the carb drain and use an additive if you can only get ethanol gas. I do a 30-60% load because that's what the ACs pull and you need to exercise those too especially in winter.

[gatorb8]

I wonder why my air cooled 22 kW Generac home generator is only programmed to run 10 minutes a week ?

[pasdad1]

Originally Posted by gatorb8

I wonder why my air cooled 22 kW Generac home generator is only programmed to run 10 minutes a week ?

The Onan diesels are water cooled, and I think they want them to run longer to be sure the coolant opens the thermostat and circulates. Air cooled get up to temp faster I believe.

[Random01]

I follow exercise schedule from the manual, 2hrs/month
I plug in portable electric heater 1500watt and run it, outside if warm the genset itself is 3600watt, tech support said its sufficient

[gatorb8]

Originally Posted by pasdad1

The Onan diesels are water cooled, and I think they want them to run longer to be sure the coolant opens the thermostat and circulates. Air cooled get up to temp faster I believe.

yes, I understand that. My question was more regarding gas air cooled generators in RVs being required to run one to two hours per month.