Generator overloads with A/C

[mesoman7]

I know this topic has been beaten to death, but I am at a loss. My Champion 3100 immediately overloads when the a/c is turned on. The a/c unit is 13.5K BTU, so the gen should handle it. My older gen has a higher capacity. It would start up the compressor. After a minute or two, it would start to motorboat then trip the 30A breaker. I can run the a/c connected to the house on a 20A circuit with no problem. OK, to mitigate the normal questions:

Refer - off
Microwave - off
Water pump - off
Water heater (elec) - off
I even shut off the converter

What am I missing here?

- Jeff

[pianotuna]

thanks for sharing the solution

[mesoman7]

FINAL UPDATE (I hope). Tried my Champ 3100 on a co-worker's trailer. Same size a/c, but different brand (Dometic). It worked. Finally broke down and ordered a Micro-Air Easy Start. Install was fairly simple.

Now comes the moment of truth...

A/c started with hardly a blink from the gen. :B Next, tried it in eco mode. Started again with no problem, although it did ramp up to full power. I never thought it would start in eco mode.

So...I guess that solves the problem. Thanks to all who chimed in.

[pianotuna]

Given the warranty situation I'd find a nice low voltage camp ground

[jdubya]

From some of the discussion I am wondering if you considered the possibility that the fan could be the culprit. A fan will run at higher current for a long time before it fails and might be enough to kick it over the edge. I think the cap for it is very cheap and has both start and run in it.

Another thing is - has the condenser coil been cleaned recently? If the compressor has to pump against too high a head pressure, it takes the max of the current to do it. Use some degreaser on it let it sit for awhile and hose it off. You should see an immediate reduction of current on the compressor run.

My Coleman Mach 8232 series rear A/C was always able to start and run at the same time on my Genset 6500 watt. This summer for the first time it refused to continue when the load was placed on it. Come to find out that the compressor was pulling enough to trip a 20 circuit breaker. Rather than work in the sun on the roof, I decided to replace them both. Just to be sure, I replaced all of the capacitors (they were old) and that did not help. So have ordered Atwood 15028 15K btu heatpump units.

[RSD559]

I would take it in and let them know that it's having trouble starting. They would test the power levels and if they are out of the spec'd range, get you a replacement.

[mesoman7]

MrWizard wrote:
I think there is the distinct possibility, that this A/C is on the way out
Two generators that should start it, do not, shore power does start it
The compressor has too much start up load
Could be , It's only a matter of time before it falls completely

I've considered that possibility. I have a little more than a year and a half left on the extended warranty, so I hope it goes quickly. I guess I should start working it to death.:B

[jillhop]

Interesting discussion.... right now I am dealing with the same issue with my still-under-warranty Dometic air conditioner. It will run when the coach is plugged in to shore power (but sometimes does labor at startup and show a 10% voltage drop on my crappy volt meter which is plugged in to one of the RV outlets) but causes the generator to shut off with a low voltage fault. I had the gen set load tested at the local Cummins service center and it was fine. On Wednesday my RV tech is going to test the start capacitor... all this is complicated by the warranty issue. I just want to start over with a new air conditioner!

[MrWizard]

I think there is the distinct possibility, that this A/C is on the way out
Two generators that should start it, do not, shore power does start it
The compressor has too much start up load
Could be , It's only a matter of time before it falls completely

[mesoman7]

jerseyjim wrote:
On the outside looking in, after reading all the posts by our "experts"...and your spending your money on thing(s) that didn't solve the problem, I might guess that the generator you are using is simply not strong enough to do what you want....irregardless of whatever the owners' manual or these guys tell you.

I wish you luck...my generator brings me to a suggestion that you get a larger generator.

((As a sidebar, my GENERAC 5500 powers both a/c units, microwave, TV, etc. all at the same time without a wimper.))

Point #1 - As far as "spending my money", the attempted solution cost me all of $11. I think I can absorb that.

Point #2 - "Get a larger generator". I have a 4KW generator also. Same problem.

[SoundGuy]

jerseyjim wrote:
On the outside looking in, after reading all the posts by our "experts"...and your spending your money on thing(s) that didn't solve the problem, I might guess that the generator you are using is simply not strong enough to do what you want....irregardless of whatever the owners' manual or these guys tell you.

I wish you luck...my generator brings me to a suggestion that you get a larger generator.

Nonsense. The OP is trying to start a 13,500 BTU A/C with a 3100 watt Champion genset that is easily capable of handling this load, as many other Champ owners would testify to. The fact he's having so much difficulty starting the A/C with the genset when shore power works fine would rather lead one to believe his particular genset may have an issue. Either that, or the A/C itself has an issue that is creating an unusually large starting load that shore power is able to compensate for but his genset won't. Suggesting his 3100 watt Champ is "simply not strong enough to do what you want" is nothing more than an erroneous WAG on your part and not helpful at all. 😞 Regardless, a Micro-Air Easy Start soft starter kit which can reduce A/C starting current surge by as much as 70% would easily solve this problem for the OP. :B

[jerseyjim]

On the outside looking in, after reading all the posts by our "experts"...and your spending your money on thing(s) that didn't solve the problem, I might guess that the generator you are using is simply not strong enough to do what you want....irregardless of whatever the owners' manual or these guys tell you.

I wish you luck...my generator brings me to a suggestion that you get a larger generator.

((As a sidebar, my GENERAC 5500 powers both a/c units, microwave, TV, etc. all at the same time without a wimper.))

[mesoman7]

UPDATE #2 - I installed the hard start cap (SPP6) yesterday. Switched on the a/c and the gen overloaded again. I tried switching off all other breakers, but no luck. I connected to house power just to see if I shorted something on the roof, and the a/c fired right up. I shut it down and waited a few minutes and tried the gen again. This time the a/c started and the gen ran fine when resetting all the breakers. I did not add any more load except for the converter/charger. It was in the upper 80s outside and probably low 90s inside.

Now, will it work out in the field...or did running it on house power corrupt the test?

[marcsbigfoot20b]

SoundGuy wrote:

marcsbigfoot20b27 wrote:
Too bad there are no performance parts for the EU2000i like carb, head, cam etc.

Try Mobil 1 synth oil in the crankcase - made a huge improvement with both of my own EU2000i gensets. Suggested by another rv.net member and I wouldn't have believed it if I hadn't tried it myself.

Already in there !! 🙂

[SoundGuy]

marcsbigfoot20b27 wrote:
Too bad there are no performance parts for the EU2000i like carb, head, cam etc.

Try Mobil 1 synth oil in the crankcase - made a huge improvement with both of my own EU2000i gensets. Suggested by another rv.net member and I wouldn't have believed it if I hadn't tried it myself.