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Old 12-23-2019, 06:29 PM   #1
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Onan 4k Overload

Boondocking on the way out here, I ran my toaster - 750w, coffee maker - 650w and tried to run my microwave - 1500w, (950w output). I hit start on the mw and as soon as it kicked in, the generator stumbled and went out like a light.

If you add it all up, it's only 2850w. The Onan is supposed to support 4k. What am I missing?

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Old 12-23-2019, 06:38 PM   #2
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Originally Posted by The_Breeze View Post
Boondocking on the way out here, I ran my toaster - 750w, coffee maker - 650w and tried to run my microwave - 1500w, (950w output). I hit start on the mw and as soon as it kicked in, the generator stumbled and went out like a light.



If you add it all up, it's only 2850w. The Onan is supposed to support 4k. What am I missing?





It was also running your lights, TV and such and charging your batteries. Did you have any heat going? Maybe tank heaters? Perhaps start up loads are higher on a microwave though I canít think why.
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Old 12-23-2019, 07:06 PM   #3
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Originally Posted by Pete'sMH View Post
It was also running your lights, TV and such and charging your batteries. Did you have any heat going? Maybe tank heaters? Perhaps start up loads are higher on a microwave though I canít think why.
Nothing I had control over. No lights, TV, etc. Batteries? Maybe. Electric shaver was plugged in. Hardly counting that.

Honest, other than the things I have most no control over were shut off/down. You make a good point about the micro start up. Nothing failed until it went into a heat cycle. Food for thought.
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Old 12-23-2019, 07:19 PM   #4
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while your generator could certainly 'handle' the wattage/amps you were throwing at it, generators sometime are finicky, and having several things 'going' all at the same time, especially high-draw appliances, and then suddenly adding a 'boooom' of microwave draw to it can bring about a sudden 'need' for power, for which the generator can't spool up fast enough, causing it to stumble, or stop.

Yes, you may also have had the CHARGER charging the batteries at that very time, on 'high charge/bulk charge' which also uses a lot of amps, which is pretty normal anytime you start the generator.

We've had our generator stumble and stop at times, not very often, but it does happen. I just restart the generator, hold the start button a little longer than required after it starts, and then let it get back to business. It usually works.


Really, if you were requiring more amps than the generator is designed for, it's own BReAKER would trip, but it's also quite possible that it's breaker(s) are actually rated higher than the output of the generator. You probably have two 20amp 'tandem' breakers, one may show on the generator, and another is behind the panel where you won't see it, or, you may have a single 30amp breaker, which is probably higher than the rating of the generator's output itself.

The rule is this:
whenever using 'morning' items, such as toasters, coffee makers, microwaves, hair dryers, the furnace, space heaters, etc.,,,,, turn off or unplug one or more of those items WHILE the microwave is running... the microwave only operates for a short time, so it's the least inconvenience, time considered.
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Old 12-23-2019, 07:26 PM   #5
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Same things happens to me on my 29M. MY BIL tells me it's rating is a 'peak' rating and it may actually run at a lower wattage. He also told me start with the highest rated load and add the lighter loads in descending order. He's an electrical engineer working in the nuclear power industry so I trust him. But it all seemed like to much to remember so I just turn stuff off to use the MW, usually one of the A/Cs.
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Old 12-23-2019, 07:27 PM   #6
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Originally Posted by TurnerFam View Post
cut...
The rule is this:
whenever using 'morning' items, such as toasters, coffee makers, microwaves, hair dryers, the furnace, space heaters, etc.,,,,, turn off or unplug one or more of those items WHILE the microwave is running... the microwave only operates for a short time, so it's the least inconvenience, time considered.
This sounds about right. I religiously run my toaster and microwave in tandem with no problems. I'll give what you offer a try. If she can't keep up, I know where I stand and what I have to do.

Thanks and Happy Holidays.
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Old 12-23-2019, 08:40 PM   #7
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"Boondocking on the way out here"....Where are you headed/at? Altitude can affect output as well.
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Old 12-23-2019, 10:11 PM   #8
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Is it also possible your water heater was on auto? If it was, add another 1440 watts. Just a thought.
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Old 12-25-2019, 05:14 AM   #9
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Same things happens to me on my 29M. MY BIL tells me it's rating is a 'peak' rating and it may actually run at a lower wattage. He also told me start with the highest rated load and add the lighter loads in descending order. He's an electrical engineer working in the nuclear power industry so I trust him. But it all seemed like to much to remember so I just turn stuff off to use the MW, usually one of the A/Cs.
It took a while but I got it.
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Old 12-25-2019, 05:15 AM   #10
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Originally Posted by The Gritz Carlton View Post
"Boondocking on the way out here"....Where are you headed/at? Altitude can affect output as well.
Tucson. Merry Christmas. Hope you're well.
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Old 12-25-2019, 01:27 PM   #11
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Fridge adds another 400 watts.
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Old 01-01-2020, 07:51 PM   #12
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Nothing I had control over. No lights, TV, etc. Batteries? Maybe. Electric shaver was plugged in. Hardly counting that.

Honest, other than the things I have most no control over were shut off/down. You make a good point about the micro start up. Nothing failed until it went into a heat cycle. Food for thought.
Also if your fridge is on auto and the electric switch is on for your hot water heater they will add to the initial load.
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Old 01-02-2020, 06:32 PM   #13
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Originally Posted by The_Breeze View Post
Boondocking on the way out here, I ran my toaster - 750w, coffee maker - 650w and tried to run my microwave - 1500w, (950w output). I hit start on the mw and as soon as it kicked in, the generator stumbled and went out like a light.

If you add it all up, it's only 2850w. The Onan is supposed to support 4k. What am I missing?

Make sure the oil is topped off. If the oil pressure drops the generator will shut itself down instead of seizing.
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Old 01-02-2020, 06:38 PM   #14
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It could be just a matter of not running everything all at once. Make tge coffee first: it'll stay hot the longest. Then run the toaster, and then fire up the microwave...
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Old 01-03-2020, 08:05 PM   #15
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there is a dial to adjust the air fuel mixture for altitude. Go open up your generator panel and adjust if you are at 3000 ft or 6000 ft.
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