A/C Question

scbrown063 · 08-16-2018, 09:26 PM

Hi all,

My Trailer has a 15,000 BTU AC and when I bought in 2015, the salesman at Camping World also sold me a 4000 Watt Generator and told me that would be plenty to run the AC. Well needless to say, at least in my case, that’s not true. So what size inverter Genny should I look at to run my AC?

nutdriver · 08-16-2018, 09:32 PM

What brand and model of generator do you have currently? Is it an inverter generator. If so, it sure seems like a 4000 watt generator should be able to run your unit.

There seems to be a lot of variation in peoples experiences. Also, I have heard of a few cases where Champion generators have had trouble running the AC but resolved through tech support by replacing a control board.

Duckogram · 08-16-2018, 10:24 PM

Quote:

Originally Posted by scbrown063

Hi all,

My Trailer has a 15,000 BTU AC and when I bought in 2015, the salesman at Camping World also sold me a 4000 Watt Generator and told me that would be plenty to run the AC. Well needless to say, at least in my case, that’s not true. So what size inverter Genny should I look at to run my AC?

Electricity is electricity. So Volts x Amps = Watts
Peak draw of a typical 15k btu A/C is about 18 amps.
Lets call it 20. Your system should be at 120v.
Thats 2400 watts. That is the mathematical answer to your question.
So now to really answer your question, one would need actual specifics rather than general bread crumbs.

scbrown063 · 08-16-2018, 11:13 PM

Quote:

Originally Posted by nutdriver

What brand and model of generator do you have currently? Is it an inverter generator. If so, it sure seems like a 4000 watt generator should be able to run your unit.

There seems to be a lot of variation in peoples experiences. Also, I have heard of a few cases where Champion generators have had trouble running the AC but resolved through tech support by replacing a control board.

I have a Champion Generator. It’s not an inverter and runs well but shuts down when I power up the AC. Even when I have everything else off.

I also have an Inverter Genny made by Ryobi that is only 2000 Watts. Been thinking I would buy a second and run them parallel and see if that works.

myxkp · 08-17-2018, 12:13 AM

I agree with previous comments; you have plenty of generator power. I'm curious about how the a/c performs on shore power and how the generator handles loads closer to its max capacity rating - a space heater and hair dryer for example.

**bikendan** · 08-17-2018, 12:18 AM

Quote:

Originally Posted by scbrown063

I have a Champion Generator. It’s not an inverter and runs well but shuts down when I power up the AC.

If it's an open-frame contractor-style generator, it won't be legal in most campgrounds.
I own a Champion 3500/4000w open frame contractor-style generator and I would NEVER use it in a campground.

nutdriver · 08-17-2018, 07:00 AM

Quote:

Originally Posted by scbrown063

I have a Champion Generator. It’s not an inverter and runs well but shuts down when I power up the AC. Even when I have everything else off.

Is this a 4000 watt generator with 220 Volt capability? If so, I presume you could only get 2000 watts out of ether leg of the power buss at 120 V. That would not be enough to run your AC.

scbrown063 · 08-17-2018, 07:40 AM

Quote:

Originally Posted by myxkp

I agree with previous comments; you have plenty of generator power. I'm curious about how the a/c performs on shore power and how the generator handles loads closer to its max capacity rating - a space heater and hair dryer for example.

When I’m hooked to 30 amp service the AC runs great and when we’re just out in the woods, “roughing it”😂 my wife uses her hair dryer no problem. The camper also has an electric fire place and micro that run fine off of the generator but only either or, not both at the same time.

scbrown063 · 08-17-2018, 07:43 AM

Quote:

Originally Posted by bikendan

If it's an open-frame contractor-style generator, it won't be legal in most campgrounds.
I own a Champion 3500/4000w open frame contractor-style generator and I would NEVER use it in a campground.

I’ve never taken it to a campground and probably never would. Yes it is an open frame contractor style. For the most part my 2000 watt inverter works fine because most of the time, I’m in a place that doesn’t require the AC but occasionally we would like to use it and can’t off the generator. Shore power, no problem. Maybe a more powerful inverter would be the answer.

jeff64 · 08-17-2018, 08:02 AM

V x A =W is true for running current or resistive loads, but doesn't take into account the power factor or starting current which depending on the size of motor and load on it, could be a bit more, at least 1.5-2X, even though momentarily.

SUPCO SPP6 Relay/Capacitor Hard Start Kit with 500% Increase Starting Torque(amazon)

Have you considered one of these, I have? There's been quite a number of threads on this and effects with generators specificly 2000 w inverters. I'm using a 3000i handi and a 13.5K and it works, but you can tell the load is on it for a few seconds even though the breaker doesn't pop. You certainly need to be conscious of what else you are trying to run at the same time. Use the search feature

inspectorgf · 08-17-2018, 08:10 AM

I have the champion 4500 starting watt\ 3650 running watt open frame generator that we use when we over night in parking lots on long trips and it powers are 15k air fine even with the residential fridge and a few other things running. You can tell it puts a load on the gen at start up but it has worked fine for us.

cavie · 08-17-2018, 08:17 AM

Quote:

Originally Posted by scbrown063

Hi all,

My Trailer has a 15,000 BTU AC and when I bought in 2015, the salesman at Camping World also sold me a 4000 Watt Generator and told me that would be plenty to run the AC. Well needless to say, at least in my case, that’s not true. So what size inverter Genny should I look at to run my AC?

Your generator is more than enough to run your AC. Install a hard start kit on your AC. $15 to $25 from Amazon. There is also a soft start kit (More$$) available. I don't know how the soft start works but have read it does.

Explain "Won't run it". Does it not start? Trip the breaker after running? 2-2000 watt with parallel hook up is a bit pricey based on your explanation of your use.

formerFR · 08-17-2018, 08:32 AM

yes, terms we use in these forums can sometimes lead to misdiagnosis/help from the rest of us since we may 'assume' you mean one thing, when you're actually 'saying' something different...

explain in much more detail exactly how you are connecting the coach to the generator, what 'size' outlet it is, i.e., 15a, 20a, 30amp, and what exactly 'won't run' really means...is the generator just shutting down/off? Is the air conditioner just not coming 'on'? Is it tripping a breaker? if so, WHAT breaker is it tripping? Does the fan for the air conditioner operate? etc etc

myxkp · 08-17-2018, 09:37 AM

Quote:

Originally Posted by scbrown063

When I’m hooked to 30 amp service the AC runs great and when we’re just out in the woods, “roughing it”[emoji23] my wife uses her hair dryer no problem. The camper also has an electric fire place and micro that run fine off of the generator but only either or, not both at the same time.

If I'm reading you correctly the generator is protecting itself as if it's in an overload situation when it isn't being overloaded. This sounds like a generator fault. Both inductive and resistive loads cause it to shut down. If I was close enough I'd test your a/c on my generator; maybe can find someone who can help you with this.
As to what size replacement will work it's back to basic math. Use volts x amps to get your wattage for each thing you might want to run. Add watts
To get your total wattage and that's the size generator you need.

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