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post #1 of 22 Old 05-03-2013 Thread Starter
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Generator to run 6000btu window ac

Can anyone recommend a generator that will run an ac like this? I am hoping a 2000 watt will be good enough, here is the ac I have...LG L6011ER: 6,000 BTU Window Air Conditioner with remote | LG USA
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post #2 of 22 Old 05-05-2013
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Re: Generator to run 6000btu window ac

The 6000BTU unit states an energy efficiency of 9.7, so 6000/9.7 is 618 Watts. In reality losses and the inefficient thermal insulation of the boat will make the unit less efficient, so take 800W as the constant load. Generators are rated at colder temps and their efficiency goes way down as they get warmer (and since you need AC it will be warm), so take 20% off your 2000W genset giving 1600W then take another 20% off that for the maximum constant running output giving 1300W realistic power when running all day.

The numbers are just examples of the math you need to do, you can plug in your own estimates. Are you planning on charging the batteries or running other items off the generator? Those would need to be added into the equation as well.


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post #3 of 22 Old 05-05-2013
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Re: Generator to run 6000btu window ac

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Originally Posted by Zanshin View Post
The 6000BTU unit states an energy efficiency of 9.7, so 6000/9.7 is 618 Watts. In reality losses and the inefficient thermal insulation of the boat will make the unit less efficient, so take 800W as the constant load. Generators are rated at colder temps and their efficiency goes way down as they get warmer (and since you need AC it will be warm), so take 20% off your 2000W genset giving 1600W then take another 20% off that for the maximum constant running output giving 1300W realistic power when running all day.

The numbers are just examples of the math you need to do, you can plug in your own estimates. Are you planning on charging the batteries or running other items off the generator? Those would need to be added into the equation as well.
You lost me Zanshin. Not seeing the purpose of you calculating the efficiency of the AC output in BTU and then making a statement about watts for operation. Your math just shows how to calculate EER or energy efficiency rating and is already provided by the manufacturer.

The AC specs show an electrical draw of 560 watts which should be RLA or running load amps. Start up loads are usual double or more for a second or two. A 1000 watt generator would probably run it but I would get a 2000 watt one, that way you are not pushing it so hard at start up and have more than 1000 watts free to run other things if you'd like unless you find the compressor cycling on and off. There isn't much cost difference between a 1000 and 2000 watt generator typically.

Last edited by FarCry; 05-05-2013 at 05:19 PM.
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post #4 of 22 Old 05-05-2013
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Re: Generator to run 6000btu window ac

I thought that the BTUs divided by the EER would give Watts, which in turn is the energy measurement most often used for generator output.

https://en.wikipedia.org/wiki/Season...ficiency_ratio

Where is my error?


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post #5 of 22 Old 05-05-2013
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Re: Generator to run 6000btu window ac

If you follow the link Sailguy provided, it shows the pertinent information in the specs. Yes you can run the numbers forward and backwards but it doesn't change the spec showing the running wattage of 560 and an EER of 10.7 on a 6000 BTU unit. We can get there your way to check LG's numbers. 6000 BTU/10.7 EER = 560 watts just like the specs say and that is the number that we need. What we don't know for sure is the starting load. That is what is needed to size the generator properly.

I do not see where your numbers are coming from in the link. I don't see the EER number you used in the link. Maybe the link has changed. There is no error in your math. Why not just take the easy path and use the numbers that are specified by the manufacturer rather than complicating it?

And yes your point of the loss of efficiency as the ambient temperature around a generator increases is a good one. Typically if the small generator we are discussing can start a motor, it will have no problem running it.

Last edited by FarCry; 05-05-2013 at 05:51 PM.
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post #6 of 22 Old 05-05-2013
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Re: Generator to run 6000btu window ac

I didn't follow the link provided, I just googled the model number to get the EER in order to compute the watts, I didn't realize it was there already.

After discussions with Fischer Panda I realized that the fine print in generator advertising/manuals is important and that genset output needs to be seriously de-rated in the tropics.

I don't know if a 6000BTU unit is going to cool a boat even if running 100% of the time.


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post #7 of 22 Old 05-05-2013
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Re: Generator to run 6000btu window ac

I see you have a 22 footer. A 6000 BTU unit is plenty big enough. On a hot, sunny day, it will struggle some , but you will be able to hang meat in there at night.

A Honda 2000 is more than enough to run that unit.
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Re: Generator to run 6000btu window ac

Ac to DC 40% loss DC to AC 40% loss hydrocarbon to electrical 60% loss, find a better way. Ice chest, evaporative cooler. or just suffer.
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post #9 of 22 Old 05-07-2013
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Re: Generator to run 6000btu window ac

You could maybe squeak by with the little 900w / 800w continuous unit that Harbor Freight sells for as little as 99 bucks (on sale, 120 normal).

Of course it's loud so you'd get run out of the anchorage.
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post #10 of 22 Old 05-07-2013
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Re: Generator to run 6000btu window ac

I just bought that HF Tools unit on sale for $89 to run my power tools and wet/dry vac. Seems adequate for the task - actually runs better under load.
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