Onan 5500 watt LP question

MTK46 · 06-30-2021, 09:55 AM

Never had this happen before.
I was running it had fridge, rear a/c, electric hot water and started the microwave. Power shut off generator still running.
I shut generator off and waited a couple of minutes before restarting it. It started but power never came back on.
Shut it down again and checked the switch panel on it.
Mine has a 30 & 20 amp switch. 30 amp was on 20 amp was off. Turned the 20 back on. Went to bed.
This morning I started the generator and all is fine.
So was it the 20 amp switch that caused the problem?
If so with the 30 one on why didn't I have some 110v power?
It couldn't have been the transfer switch as I plugged in my cord to a 15amp plug and did have power.
To tell you the truth I never paid any attention to the switches on the generator before.
As I bought my MS used and the hour meter wasn't working I don't know how many total hours are on it.
I changed it out right away and in two years I've put 65 hours on it. I don't think it had a lot on it when I bought it.

So any ideas?

**wingnut60** · 07-01-2021, 09:33 PM

Mike,
I had a 5500 Onan Marquis in my '05--changed it to the '15 when traded for it. In the total 13 years I had the two units, the gen never failed to operate. Only changed oil/filters twice. Had somewhere around 500 hours on it total in 13 years. Never had the same thing happen that you had. Can't help with an answer.
Joe

Dan50 · 07-05-2021, 03:34 PM

I have heard of a few people with the same problem. The 20 amp breaker trips on the unit pops and you lose all power. The Onan comes in two variations. A 20 amp breaker and a 30 or two 30 amp breaker. The fix is to change out the 20 for another 30.

MTK46 · 07-05-2021, 03:42 PM

Thanks I'll look into that.

bones95949 · 07-06-2021, 03:56 PM

I have the same gen as you do. My 20 amp breaker does pop on occassion when I overload it with usually kitchen items. obviously the 20 amp can't take the draw that the 30 can. Don't really think there is a fix for it, other then to not try to draw so much power. Think I have read something about it only being 45 amp max draw. However don't think changing the 20 amp to a 30 is a good idea. I just live with what it is and know it's limitations. Good luck

dmorse68 · 07-07-2021, 11:04 PM

Yeah MTK46, that’s normal. You ran too many big draw items on that 20 am circuit. With the AC and the microwave, it didn’t have a chance. Just be mindful, and watch your amp
Draw on each leg, on the “RV POWER MONITOR FOR ATS” display in the entry closet and you’ll be fine.

MTK46 · 07-08-2021, 08:10 AM

I did read that max amps is 45.8 for this generator. As this is the first time it has happened I now know the limit.

Thanks for all the help!
That's why I'm on this site. Been RVing for 35+ years and still learning. Had the same generator in a Toy Hauler and never did it. First time for everything.

dmorse68 · 07-08-2021, 08:17 AM

I know huh. Still learning too and first time for everything.

You think they would design the gen to handle a total of 45 amps no matter which leg it’s on. But I think it’s DRV’s design that is the main issue. I noticed (at least in my ‘18 36RSSB3) that the big draw appliances are mainly on one leg. If it were me, I’d split them up on both 220v legs evenly.

MTK46 · 07-08-2021, 09:14 AM

I do know that I can run the rear a/c and microwave with the fridge at the same time. We do it all the time with the generator. Kicker was the water heater.
Oh and I don't have any info amp draw on the inside of my door.

Dan50 · 07-08-2021, 10:30 AM

Quote:

Originally Posted by bones95949

I have the same gen as you do. My 20 amp breaker does pop on occassion when I overload it with usually kitchen items. obviously the 20 amp can't take the draw that the 30 can. Don't really think there is a fix for it, other then to not try to draw so much power. Think I have read something about it only being 45 amp max draw. However don't think changing the 20 amp to a 30 is a good idea. I just live with what it is and know it's limitations. Good luck

Onan themselves suggest changing the 20 amp to a 30 Aamp btraker.

MTK46 · 07-08-2021, 05:08 PM

I just looked at my main breaker panel and the water heater is on the other leg.
Now that I know what's on each leg I'll be more mindful of what's on when using the generator.

Notanlines · 07-08-2021, 05:37 PM

MTK, it may have been mentioned, but your water heater has no business on electric when you have the generator cranked unless you're out of propane.

DMW · Yesterday, 12:53 PM

Just a few comments on our electrical power service in this country.

The electrical standard in this country is 120 volts +/- 10 volts. Not 110 volts. Consequently, manufacturers of consumer appliances publish their product specifications at 120 volts, and build them to work on 110 - 130 volts. But remember, their current draw is given at the 120 volt standard. You can see this on the tags that come on the power cords on your floor fan, microwave oven, coffee pot, etc, etc.

What this means is, an 1,100 watt microwave oven drawing just a hair over 9 amps at 120 volts will draw 10 amps at 110 volts. That's a 10% increase in current draw. If you add another appliance or two on the same circuit drawing 10% more current than the manufacturer publishes, and things work fine much of the time, the additional current draw due to low voltage may be enough to trip the breaker on occasion, even though everything works fine again a little later. After everyone has had a shower and dinner and is kicked back watching TV, everything might be fine again.

Breakers get weak over time and will trip sooner than they used to. The only fix for that is to replace the breaker and throw the old one away.

In the evenings, when demand for power is high, the line voltage will go down. The greater load, with a greater current draw, pulls the voltage down. And the lower the voltage goes, the higher the current draw goes. This usually is in the evening hours when people are fixing dinner, watching TV, taking showers with water from electric hot water heaters, and with every light in the house on. Oh yes, we can't forget the air conditioners and perhaps the laundry machines. So just the time of day makes a big difference in our current draw and line voltage. If you make a note of the time of day and the line voltage, you might find this is a real problem. And it can be a real pain in the neck in some parts of the country.

My Progressive EMS works over the range from 110 volts to 130 volts before it shuts me down. And it won't power up again for two minutes nor until the line voltage comes back within that range, whichever is longer. I have the big Progressive EMS that I have chained to the power pedestal. I forget the model number. It shut me down once in two years due to low voltage. Later in the evening, everything was fine. During that time, my onboard generator set worked just fine, thank you. lol.

There are many appliances in our RVs that draw a lot of current. Any motor, compressor, or heating element are relatively big current draws. Space heaters can be huge current draws relatively speaking.

If you want to try to minimize your power usage, you might consider not using some of these high current items while others are in use if you can. If not, you may find a breaker trips more often, and you may not find anything wrong anywhere, until you check the line voltage. And yes, low voltage/high current can and does fry IC control boards sometimes because the higher current generates more heat. Can you say "Ka-Ching"?

Happy trails.
Dave