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rvmorkie · 08-29-2016, 06:19 PM

Our 2006 Winnebago Sightseer has a Onan 4000 Micro Quiet generator. Seems like over the last couple years (this last week especially) the main breaker on the Onan 4000 generator trips off. I think it should be able to handle more than it does before this should happen.

If we operate the air conditioner, the inside and outside radios, a fan, a couple lights, and then use the microwave the main breaker trips off. Should this be able to handle all this or is there a problem?

Thanks.

jacwjames · 08-29-2016, 06:35 PM

4000 watt generator is good for 4000/120 volt = ~33 amps but only can use ~ 30 amp continuously.

The AC unit probably uses ~15-18 amps, the lights and radio are minimal but the microwave could use ~10 amps depending on wattage.

If you have any way of checking the amperage on the AC and Microwave it might help you see if something is wrong. As the AC unit fails it will draw more amperage. Could be the fan or the compressor.

Bottom line is it is border line.

twinboat · 08-29-2016, 06:43 PM

I was having exess amp draw from my AC.

I got on the roof, pulled off the cover and took a garden hose to the condenser coils. I was careful not to bend the fins with the pressure.

My measured amp draw went from 19 amps down to 15. That was a year and a half ago and all has been fine.

It's worth a try.

ahicks · 08-29-2016, 06:52 PM

Keep in mind circuit breakers are thermally activated, that's how they sense an overload. In warm weather, or say when working in an area that not ventilated well enough to let the heat escape, the breaker is going to pop early - possibly with loads less than it's rated for. Just a thought....

spyderRV · 08-30-2016, 12:56 AM

My gen has not popped a breaker even when I had an AC with a sometimes shorted start cap. It would drag the gen down and it would shut off.

twinboat · 08-30-2016, 03:09 AM

Quote:

Originally Posted by spyderRV

My gen has not popped a breaker even when I had an AC with a sometimes shorted start cap. It would drag the gen down and it would shut off.

If the generator can't make its rated power, that sounds like an engine problem.

ahicks · 08-30-2016, 06:55 AM

Or a breaker that was not letting go when it should?

twinboat · 08-30-2016, 07:18 AM

I though of that, but wouldn't the generator output drop off, and the engine struggle along ?

It's more like fuel starvation. The carb bowl empties and the engine dies.

Rockwood27 · 08-30-2016, 07:28 AM

Don't forget the converter is converting and the refrigerator may be on electric when the generator is on. Combined, they could be drawing over 5 amps. Do you have a water heater on electric?

jacwjames · 08-30-2016, 07:32 AM

Yup, those minor loads add up.

Rule of thumb for a 4000kw generator would be to shut off AC if you want to run the microwave.

We have an Intellitec EMS system that will limit consumption if hooked up to a 30 amp source, which is ~3600kw. We can run 1 AC unit but not any other major loads and switch the refrigerator and water heater to propane.

jtermini30 · 08-30-2016, 08:52 AM

We had a similar issue in a former class C and needed to shut off the AC when the microwave was on.

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Waiter21 · 08-30-2016, 09:17 AM

You're over your power budget when you attempt to run the AC and the Microwave at the same time. Especially if the compressor is cycling and attempts to start.

You may need to change your procedures when you want to use the microwave, i.e. turn the AC unit off.

Depending how your AC unit is controlled . My AC unit control is on the ceiling, so we reach up and turn it from COOL to FAN, then when we're done with the microwave, we turn it back to COOL.

MSGDLD · 08-30-2016, 10:14 AM

I'm in agreement with those that think you're asking too much for a 4K generator. Is it 4K peak or continuous? Even at 4K continuous, you'd be pushing it. On 30AMP shore power, which is close to a 4K continuous generator, I can only run either the A/C or the Microwave, but not both. It wouldn't do that new.

Good idea on cleaning the A/Coils, I should probably do that.

BTW, in my experience, after breakers trip a number of times they get weaker to throwing of going bad.

milasman · 08-30-2016, 10:07 PM

If you would like an idea of what the amp draw is with A/C running on my RV, a 2012 Fleetwood Jamboree it is 16.7 amps. A/C and microwave is 26.7 amps. A/C and coffee maker is 22.1 amps. A/C, toaster, and electric hot water is 25.7 amps. All these measurements taken with refrigerator on electric, inverter running, and step lights on.