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Normal for onan 12.5kw to die when coming off shore power?

doublev
Explorer
Explorer
With the heat, I like to fire up the generator while plugged into shore power. I dont know if this is a problem or not but when the coach flips over to the generator (which it will do after 20 or 30 seconds of starting it up), the generator will die immediately if I have a full load on it (3 AC units and all that fun stuff).

My fix is to turn the AC off for about a minute to let the generator warm up and then I will turn on 3 AC on and it is fine (in the interim all of the other house items are putting some load on the generator).

Is this normal? I tend to think a generator probably does not like going from 0 amps to 50-60 amps instantly (about 25-30a per leg) 30 seconds after it has been turned on. But I want to double check and if it is not normal, what does this tend to indicate as a problem?

Generator otherwise works great. We can run it all day without any issues at all.
5 REPLIES 5

Effy
Explorer II
Explorer II
I think it's more akin to starting your car on a cold morning, flooring the accelerator and slamming it into gear. I am surprised you haven't seriously damaged anything.

This has been debated before but I always go under the practice of unplugging before starting the genset. But yes you need to let them come up warm before throwing an AC on, let alone 3 at the same time.
2013 ACE 29.2

Busskipper
Explorer
Explorer
Ivylog wrote:
While I do not disagree with Mr. Wizard, I would do it slightly differently. A minute after starting the generator, not five minutes, I would start one AC. A minute later the second AC and at three minutes the third.

If it's really cold out and you are going to need the generator then I would give it 4-5 minutes before putting a load to it.


X-2 Sums it up pretty well - just like most things just ezz in to it.

BOL,
Busskipper
Maryland/Colorado
Travel Supreme 42DS04
GX470-FMCA - Travel less now - But still love to be on the Road
States traveled in this Coach

Ivylog
Explorer III
Explorer III
While I do not disagree with Mr. Wizard, I would do it slightly differently. A minute after starting the generator, not five minutes, I would start one AC. A minute later the second AC and at three minutes the third.

If it's really cold out and you are going to need the generator then I would give it 4-5 minutes before putting a load to it.
This post is my opinion (free advice). It is not intended to influence anyone's judgment nor do I advocate anyone do what I propose.
Sold 04 Dynasty to our son after 14 great years.
Upgraded with a 08 HR Navigator 45’...

MrWizard
Moderator
Moderator
doublev
yes what you describe is NORMAL and is hard on the generator
you should NOT do it that way

best to turn OFF all A/Cs unplug shore power
start generator, let it warm up 5 minutes
then start A/c "one at a time"

you are right it does NOT like going from 0 to 60
I can explain it to you.
But I Can Not understand it for you !

....

Connected using T-Mobile Home internet and Visible Phone service
1997 F53 Bounder 36s

1BryNelson
Explorer
Explorer
You should turn off all major power draws and should unplug from shore power before firing off the generator. Let it warm up a bit before loading it. Kinda like starting your vehicle and letting it warm up before flooring the gas pedal.
Bry Nelson and a yet to be discovered MoHo momma. '99 Pace Arrow Vision 37ft F53 chassis (plugs tightened) Allure flooring, 15k BTU front a/c , 6-6 volt batts with 1120 watts of solar Magnum inverter Remote BMK Trace C40 2005 Ford Ranger "Toad on a pad".