Run a 120V portable A/C on an inverter?

I have a Cobra 2500 modified sine wave inverter and a portable 8000 BTU 120V A/C (draws about 8 amps running & about double at start up) so hooked them up and the A/C would run sometime but the inverter alarm never shut up. The plain fan runs fine. Cobra said I need a full sine wave inverter and Edgestar A/C says they have no idea what it will take to run their unit off an inverter.

I see full sine wave inverters with prices and specs with huge variances. Just wondered if anyone is running some AC equipment with a pure sine wave inverter & which units work well?

I do not want a marine water cooled A/C as I go to any length to not winterize anything as I keep my boat on a lift year round. I also do not want a roof A/C. For the few hot days of summer thought I'd throw the portable A/C in the cabin (fits in there like a glove) and in the winter maybe a ceramic heater. I usually run out for only an hour or two and looks to me that the Yammie 150 4S puts out about 38 amps at WOT so should keep up with my AC load.

Thanks,

Pete K.

Home Depot, etc have smaller window AC units in 4000 - 5000 btu range that will draw less juice or look at floor portable units
ex
http://www.buy.com/prod/mobilcomfort-80 ... 69792.html

These can be secured in place with straps

Most folks should use a genset like a Honda 2000 for power

Do you have battery bank for the inverter? or direct feed from the motor?
If you have a Kill A Watt meter you can measure the draw. Less than $20 onsale with free shipping at Meritline.com

8 amps at 120vac is no less than 80 amps @ 12vdc. The Yammy won't keep up. And you should probably have 4 gauge cable between the inverter and battery to accommodate losses.

Pete, I don’t think is going to work out for you. Along the lines of what Nick said:

Watts = Amps x Volts

So if the unit requires 120 Vac and 8 Amps it consumes 960 Watts when running and 1920 Watts at startup (since you said it is double). Then the efficiency of the inverter is probably 80% to 85%, so the current required to run the A/C off of the inverter is:

Amps = 960W / (12Vdc x 0.80) = 100 Amps

Plus, you need to double that for startup and remember you need power for everything else you are running, including the motor. Additionally, you should be considering the current generated at idle, not WOT (unless you are only running the unit at WOT). Even then that assumes you will never have the unit running when the motor is off; for that you need to know the current the batteries can supply and for how long. I think you need a smaller unit or a genset.

Gary

We used an R2D2 unit in the van until we put in the window unit.

They require a goodly supply of outside air which gets blown out the hose so your best bet is to be in the exiting flow of cold air. The two hose versions are much more efficient, but for us one hose was enough hassle. Ours now has a place in the living room so when my wife has hot flashes we can cool her down right away without doing the whole house. :lol:

Anyway what I'm getting around to saying is that we found our Pelonis unit very fussy powerwise. Our Honda 2000 couldn't always make the R2D2 unit happy. Sometimes it would start it and sometimes it wouldn't, and on occasion the A/C would shut down by itself during a new compressor cycle. In other words, a warning not to go in blindly thinking that a generator will be a simple answer.

On the other hand, my Honda EU1000 regularly starts/runs my 6,000 BTU window unit, even from Eco-Throttle.

Well, as usual, the best advice is on this forum.

I talked to Honda generator, Edgestar A/C, Cobra inverter and Xantrex inverter engineers and ran some tests on my Cobra modified sine wave 2500 inverter.

Bottom line is I need a generator if I must satisfy my obsession to have an 8,000 BTU portable A/C which needs 16 amps to start and about 8 amps to run.

There is some question as to which generator as the Honda folks say their 2000 (47 lbs.) will not do the job so they suggest the 3000 which is too much weight (134 lbs.) for me to handle. The Yamaha 2400 (75 lbs) might do the job, but I want to try it before buying. It is quieter than the Honda and the weight is manageable.

On the inverters, there are modestly priced modified sine wave and much more expensive pure sine wave inverters. The inverter people say the best way to know which one you need is to test what you want to run on the inverter. Unless you are an electrical engineer or just bright, it is too hard to tell which motors or devices will work. They all say cheaper inverters will do fine with most hand held electric drills, jig saws, etc. and this is true on mine as was an 18 inch fan. When I tried to run a low amperage ceramic heater, it started okay but the voltage dropped quickly on the battery and soon set off the inverter alarm - even with my Y 150 4s running. So to have good reliable heat and PORTABLE air I need a properly sized generator on my boat. Marine air, window air and roof air are a different story as most can run on lower cost modified sine wave inverters if you have enough battery juice.

The portable airs really start at 8000 BTU if you want one where you do not always have to empty the water container or have it drain into the bilge. Smaller airs are available as roof and window units. I will have to exhaust the hot air out of the cabin if I end up using the portable.

I just called the local Honda store & they will let me try my portable A/C on a 2000 and a 3000 if the 2000 cannot do the job. The local Yamaha generator store says I can try theirs and they carry a 2000, 2400, 2800 and a 3000. They have inverter supplied power in most of these generators so the juice is closer to a pure sine wave. So will report back after I find the time to make these test trips.

Thanks for the feedback..........................Pete

great info, thanks

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greatcir,
You've done a lot of research/thinking. Let me add some of my experiences.

I tried very hard to put the R2D2 unit in MokeeDugway (2120). Yes, it fit nicely, but it needed to be secured well to keep from being a menace in nasty seas...and the ventilation hose was such a hassle both in use and in storage, not to mention the Honda 2000 wasn't reilably up to the task. I have a Honda 3000i on my camper and love it. Not only does it have a key fob remote start/stop, we run it in stealth mode inside the box.

The 3000 was however, too big/unmanagable for the 2120.

I'm sure all of us will agree, that the water cooled internal air conditioner is the most sanitary and generally preferred installation, but it is more expensive and complicated, and will not work when the boat is on the trailer.

Cutting a hole in the roof of a Parker is heresy, and putting an air conditioner unit on the roof is tacky, but my wife has MS and doesn't do well in the heat, so that's what we did. One hole, 3 wires and 4 fasteners later we had a nice cool cabin, with no sacrifice of space and we could run the air conditioning while WallyDocking (camping in WalMart parking lots). There's plenty of boaters out there who wish they had the guts to do the same.


Bottom line, you can't beat the simplicity, cost, or effectiveness of an R/V air conditioner on the roof of your Parker.



On our 18' Seaswirl, we use a 6000 BTU window unit and a Honda 1000i.


And the van got a 9000 BTU window unit for camping without the boat.

The 2000i is in the white handicap box.

Took my 8,000 BTU Edgestar portable A/C to the Yamaha generator dealer (motorcycles are his business)) who also sells the Honda generators. He thought the Yamaha EF2000IS was the generator I needed so he put gas & oil (will not run with low oil level) in it and we plugged in the A/C and waited for the compressor to kick in. It all worked fine.

I also took a ceramic heater to test and it worked well on high setting so can I can use this generator year round.

The A/C stalled out the generator once in the economy (quiet, lower fuel consumption) mode but never flinched much on the normal running setting as the overload light would just flicker when the compressor turned on. It weighs 44 lbs. dry and has a three year warranty & sold for $999 today. I brought is home and let it run for an hour with the A/C plugged in. It makes some noise under load, but I would have the cabin door closed for the A/C (or heat) so not a problem.

Now need to install all on the boat. May look for a metal generator cover to bolt to the deck with a lock on it if reasonably priced. Have seen a few with louvered exhaust cut outs and an opening to the pull handle, fuel, etc..................Pete

It has been my experience that if the gen fails in Eco-throttle, it's a sign that you may have problems in regular mode on very hot days. All my A/C units are much easier to start/cycle in cooler temps.

Everyone have carbon monoxide CO detector with those gensets?

salbrent":17nyt20n said:

Everyone have carbon monoxide CO detector with those gensets?

Click to expand...

Always nice to have a reminder.

We use two - one fixed in the sleeping quarters (both boat and van) and the other is moved to where we are. I like these 'cause it's comforting to know about CO levels before the alarm sounds.


A couple weeks back, I was rafted to a 29' Sundancer on a lake. He started up his genset after I had gone to sleep but thought to place his remote CO detector at my head before turning in. I was 'alarmed' awake by both his and my detectors in the middle of the night. I untied my boat and dropped anchor away from his exhaust. Moral of the story, drop your guard and you could be dead - even if it's not your generator!

great thanks