Run 2 a/c?

[porthole]

So, back to the original poster. I have a similar trailer to yours, and when I don't have any issues or excessive heat i can run both of my AC's, the converter (sometimes draws as as much as 12-14 amps), and the water heater.

I found, and you may want to check, that my 120 AC loads were not evenly distributed in the panel.
IIRC, the hot water heater, converter and one of the AC's were on the same power leg in the breaker panel. That is a roughly 35-40 amp plus draw on a 30 amp breaker protected supply.

Maybe if your battery is charged up enough, the converter only pulling 5-10 amps, the AC 12-15, the water heater currently off, but maybe a few other circuits on totaling around 30 amps on breaker #1 you are within the genny's 30 amp supply. Then you fire up AC #2, that may or may not be on the same output breaker, with a 15 amp draw (maybe higher on the startup) you have now just reached the max of the rated output, 120 volts drawing 45 amps.
So, something trips.

Rated output also changes with ambient temperature and elevation.

From Onan's spec sheet:

Ambient conditions for rated power output with muffler and RV enclosure, per ISO 8528-1:
- Temperature: 77° F (25° C)
- Altitude: 500 ft (152.4 m), (99 kPa dry)


Typical power output change based on ambient conditions:
- Temperature: Power output decreases 1% for every 10° F (5.5° C) increase
- Altitude: Power output decreases 3.5% for every 1000 ft (305 m) increase
Ratings represent minimums. Actual performance may be significantly higher based on installation and operating conditions.

There are startup capacitor kits that you can add to your AC units for a relatively low price. These are documented on the forum. This may help as well.

I moved the feeds around for several different loads to try and even up the load on the panel as best as possible.
Your panel has A & B sides to it - hot feeds with black and red wires. If your first breaker was A, then every other breaker is A, 2nd breaker B, then every other is then B

Get a piece of paper and write it all down and then look to see if you need to have the loads moved around.

And - as one of our presidents said, trust - but verify. Just because the breaker may be labeled "garage" does not in fact mean it really feeds the garage.

 

[Jim.Allison]

If the circuits were unbalanced, wouldn't it just throw the main breaker when the load was exceeded? Whatever it is, I think we all agree that there is something wrong and that both air conditioners can be supported by a 5500 onan.

So, back to the original poster. I have a similar trailer to yours, and when I don't have any issues or excessive heat i can run both of my AC's, the converter (sometimes draws as as much as 12-14 amps), and the water heater.

I found, and you may want to check, that my 120 AC loads were not evenly distributed in the panel.
IIRC, the hot water heater, converter and one of the AC's were on the same power leg in the breaker panel. That is a roughly 35-40 amp plus draw on a 30 amp breaker protected supply.

Maybe if your battery is charged up enough, the converter only pulling 5-10 amps, the AC 12-15, the water heater currently off, but maybe a few other circuits on totaling around 30 amps on breaker #1 you are within the genny's 30 amp supply. Then you fire up AC #2, that may or may not be on the same output breaker, with a 15 amp draw (maybe higher on the startup) you have now just reached the max of the rated output, 120 volts drawing 45 amps.
So, something trips.

Rated output also changes with ambient temperature and elevation.

From Onan's spec sheet:

Ambient conditions for rated power output with muffler and RV enclosure, per ISO 8528-1:
- Temperature: 77° F (25° C)
- Altitude: 500 ft (152.4 m), (99 kPa dry)


Typical power output change based on ambient conditions:
- Temperature: Power output decreases 1% for every 10° F (5.5° C) increase
- Altitude: Power output decreases 3.5% for every 1000 ft (305 m) increase
Ratings represent minimums. Actual performance may be significantly higher based on installation and operating conditions.

There are startup capacitor kits that you can add to your AC units for a relatively low price. These are documented on the forum. This may help as well.

I moved the feeds around for several different loads to try and even up the load on the panel as best as possible.
Your panel has A & B sides to it - hot feeds with black and red wires. If your first breaker was A, then every other breaker is A, 2nd breaker B, then every other is then B

Get a piece of paper and write it all down and then look to see if you need to have the loads moved around.

And - as one of our presidents said, trust - but verify. Just because the breaker may be labeled "garage" does not in fact mean it really feeds the garage.

 

[Jim.Allison]

Well my leads are outside my generator, so I dont have to open the stator. Perhaps you might. But hey back to the OP as you say.

This is perfectly clear now.

So, if I open up my Onan genset and find where the 2 hot output wires T1 and T3 are coming off the stator, and cut that connection, marked in red
and
find where the two neutral wires, T2 and T4 are coming off the stator and cut that connection, marked in blue
and
maybe cut the bonding at the marked in black location and double the ground coming out of the generator

I could then have two hots, two neutrals and the ground

And, it looks like the genset only has to be disassembled to the stator - rotor level to get to the ground screw and break the connection there (page 6-2 of the above link).

I could then have two separate 120 circuits coming off the two 30 amp breakers instead of the two 120's that are actually combined prior to the breakers, from what appears to be nothing more then a shared feed, as built from the factory.

View attachment 31079


What I don't understand is why Onan only rates this genset at 45.8 amps (5500/120) when it should really be rated at 7200 watts (120*30*2), if I were to follow along correctly.