15K BTU A/C and Generators

[GeoffW90]

Okay... so I have been to my dealer, I have researched the internet from end-to-end, and I am still unsure of what my generator selection should be.

I bought a Firman 3300 from Costco, it was a piece of junk... Lesson learned, going to buy a Honda or two.

Anyone running generators with a 15K BTU a/c - does a Honda 3000 inverter generator have enough or should I go and get two 2000's and parallel them? I want real facts, so to RV.net I go.

Thanks in advance for your insight!

[Huntindog]

totaldla wrote:

ryanw821 wrote:

It's really not a problem, the compressor isn't constantly cycling, the AC also must cool down the compressor before it will let it try to restart, there's plenty of time for the hard start to cool adequately too.

Not sure I follow. The system uses a fixed orifice tube, so the only way to adjust for a certain temperature is to vary the duty cycle of the compressor - i.e. cycle on and off. My only concern with hard-start caps is that they don't work for repeated cycling and 2kw inverter generators will overload.

I know the situation gets worse with high altitude and/or high outside temp.

I should point out that I'm only dissing hard start caps that use a PTC as the relay type should handle cycling just fine.

Being in Arizona, I know how it works in high heat.... Lets just say that cycling is not an issue.

[memilanuk]

otrfun wrote:
If I was having your problem, I'd be checking the inrush (startup) current and double-checking the continuous current with a handheld, clamp-on ammeter while on shore and generator power.

Probably not a bad idea - I've got a Fluke 33 that's been collecting dust for a while now... might as well make it earn its keep 😉

Depending on the readings you may have a problem with your Champion 3100, your a/c, or maybe you've got more turned on in your trailer then your realize. In that case, it's just a case of operator error.

Entirely possible - this was a 'used' 2018 model that the dealer had gotten on trade, and we've found a number of things that we missed and/or weren't mentioned during the walk-thru, like a outdoor gas BBQ hook-up line (cool) or where the blue blazes is the switch for the flood lights on the front nose (still have no idea).

[memilanuk]

2oldman wrote:

memilanuk wrote:
With the A/C running it showed 21 amps @ 117 volts... which by my math works out to ~2450 watts... which seems kinda high.

Yeah, real high. You sure the WH wasn't on?

WH? Water Heater... you mean the DSI *gas* water heater?

[neil57]

My Firman 3300 also runs a 15k ac without issues, in eco mode it kicks in and starts right up.

[2oldman]

memilanuk wrote:
With the A/C running it showed 21 amps @ 117 volts... which by my math works out to ~2450 watts... which seems kinda high.

Yeah, real high. You sure the WH wasn't on?

[otrfun]

memilanuk wrote:
. . . FWIW, for the second night we moved over to a site with power & water, and I plugged in the trailer with the EMS protector on the cable. With the A/C running it showed 21 amps @ 117 volts... which by my math works out to ~2450 watts... which seems kinda high.

If you were only powering the one a/c unit, that's very high. We have two 15k a/c units. On our EMS (50 amp version) our a/c's typically read anywhere from 12 - 15 amps each. They only draw 15 amps when ambient temps are very high (100+).

If I was having your problem, I'd be checking the inrush (startup) current and double-checking the continuous current with a handheld, clamp-on ammeter while on shore and generator power. Depending on the readings you may have a problem with your Champion 3100, your a/c, or maybe you've got more turned on in your trailer then your realize. In that case, it's just a case of operator error.

[memilanuk]

Yeah... I'm going to have to be a voice of dissent on this one. Not impressed with the Champion 3100 running our 15k BTU A/C unit.

We got a Champion 3100i (gas, with electric start) a couple years ago. Got a 2018 Cougar 28 RLSWE a few weeks ago, and last weekend we took it out on a trip. First night we set up to dry camp, as our desired location was full.

Set up the generator, plugged in the shore power cable and... blinking red overload light, that wouldn't clear until we unplugged the cable and shut down the generator. Nothing on in the trailer besides maybe the refrig (on auto).

Had to get the generator up and running, choke off and economy mode off, and *then* plug in the cable (still nothing turned on in the trailer) before the generator would accept the 'load'.

Then we tried starting the 15k BTU A/C unit. Trip.

Had to go thru the whole rigamarole of unplugging the generator, starting it, etc. etc. then plugging it back in, then starting the *fan* only on low speed, and after the generator loaded up, *then* moving the controller to 'A/C'.

Once there it seemed to run fine... but it was a whole lot more of a PITA to get there than I had expected from reading this thread (and others). Maybe there is something wrong with our gen set?

FWIW, for the second night we moved over to a site with power & water, and I plugged in the trailer with the EMS protector on the cable. With the A/C running it showed 21 amps @ 117 volts... which by my math works out to ~2450 watts... which seems kinda high.

[Clockman]

Just get a Champion 3100 Gas Only model , it weighs 85lbs and has a 30 amp plug... Done deal..It only like $700 online from Costco and you don't need to be a member to buy ...I have run mine in 105 degree Temps for 12 hours straight for a week running the A/c and it never let me down...

[ryanw821]

totaldla wrote:

ryanw821 wrote:

It's really not a problem, the compressor isn't constantly cycling, the AC also must cool down the compressor before it will let it try to restart, there's plenty of time for the hard start to cool adequately too.

Not sure I follow. The system uses a fixed orifice tube, so the only way to adjust for a certain temperature is to vary the duty cycle of the compressor - i.e. cycle on and off. My only concern with hard-start caps is that they don't work for repeated cycling and 2kw inverter generators will overload.

I know the situation gets worse with high altitude and/or high outside temp.

I should point out that I'm only dissing hard start caps that use a PTC as the relay type should handle cycling just fine.

Maybe I could have worded that better, by "cool down the compressor" I mean wait for a few minutes before cycling it back on, most wait 5-10min, plenty long for the PTC to cool back down.

[totaldla]

ryanw821 wrote:

It's really not a problem, the compressor isn't constantly cycling, the AC also must cool down the compressor before it will let it try to restart, there's plenty of time for the hard start to cool adequately too.

Not sure I follow. The system uses a fixed orifice tube, so the only way to adjust for a certain temperature is to vary the duty cycle of the compressor - i.e. cycle on and off. My only concern with hard-start caps is that they don't work for repeated cycling and 2kw inverter generators will overload.

I know the situation gets worse with high altitude and/or high outside temp.

I should point out that I'm only dissing hard start caps that use a PTC as the relay type should handle cycling just fine.

[ktmrfs]

totaldla wrote:
Some "hard-start" use a PTC to isolate them from the circuit. A PTC has to cool down before the cap can help with a start. Since compressors cycle on and off, the hard-start cap will only help once or twice after which the generator will overload.
The Micro-air "Easy Start" is the only real solution for 2KW generators.

unless the AC unit tries to recycle fast, like in less than 5 minutes the PTC will be cooled down. And most AC units won't start for between 5 and 10 minutes after a shutdown anyway to let head pressure drop.

now all that said, the microair easy start solves the starting problem, it doesn't solve any issues with running current and the honda 2000 with our coleman MachIII is near the honda limit. works fine to somewhere above 3500-4500ft. ok at 3K feet, overloads at 4500ft after running for about 10 minutes.

[ryanw821]

totaldla wrote:
Some "hard-start" use a PTC to isolate them from the circuit. A PTC has to cool down before the cap can help with a start. Since compressors cycle on and off, the hard-start cap will only help once or twice after which the generator will overload.
The Micro-air "Easy Start" is the only real solution for 2KW generators.

It's really not a problem, the compressor isn't constantly cycling, the AC also must cool down the compressor before it will let it try to restart, there's plenty of time for the hard start to cool adequately too.
Micro-air is probably the only solution for a 2k gen (and looks like a very nice device), but really no one should be running a 15k AC from a single 2kw gen (maybe a 13.5k AC though), even if the micro-air lets you. Once running a 15k AC would be pulling the maximum load a 2kw gen could sustain (1600watts on most) which is hard on the generator to be run at 100% load constantly, and could lead to premature generator failure.

[BCtoAB]

GeoffW90 wrote:
Okay... so I have been to my dealer, I have researched the internet from end-to-end, and I am still unsure of what my generator selection should be.

I bought a Firman 3300 from Costco, it was a piece of junk... Lesson learned, going to buy a Honda or two.

Anyone running generators with a 15K BTU a/c - does a Honda 3000 inverter generator have enough or should I go and get two 2000's and parallel them? I want real facts, so to RV.net I go.

Thanks in advance for your insight!

Well i just ran the 3300 firman from costco last weekend for the first time. she kicked on and ran my 15k ac unit no problem. I am also in high altitude. Tried it the second time while on eco mode and she kicked the ac on again without any issue.

[berniedes]

Interesting that you find it "Junk" I got one of them at costco. Runs quiet , not too heavy and easy to move around and it starts the AC in my Starcraft Autumn Ridge 266RKS no problem .

I love this little generator, runs everything no problem.

[Hannibal]

Being a retired electrician/elevator mechanic, I like to have twice the rated capacity for the expected load. I have a Dewalt/Generac 7k watt gen. Heavy and fairly noisy but does the job very well.