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

Question

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.

1brynelson · Answer

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.

mrwizard · Answer

doublevyes what you describe is NORMAL and is hard on the generatoryou should NOT do it that waybest to turn OFF all A/Cs unplug shore powerstart generator, let it warm up 5 minutesthen start A/c "one at a time"you are right it does NOT like going from 0 to 60

ivylog · Answer

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.

busskipper · Answer

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,

effy · Answer

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.

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

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