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Anyone Running A AC Unit From A Modified Sinewave Inverter

tbuechner

Just an average Joe that like solar
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Colorado Springs, CO
On my RV I want to know if anyone is been running a air conditioning unit on a modified sine wave inverter. The plan is to use a 3000W inverter to be able to run the AC unit for a couple hours a day.
I am trying to decide if I really need to get a pure sine wave inverter or if a modified sine wave will work fine. I know there are issues with electronics on a modified sine but will it bother the AC unit.
 
On my RV I want to know if anyone is been running a air conditioning unit on a modified sine wave inverter. The plan is to use a 3000W inverter to be able to run the AC unit for a couple hours a day.
I am trying to decide if I really need to get a pure sine wave inverter or if a modified sine wave will work fine. I know there are issues with electronics on a modified sine but will it bother the AC unit.
BTW, did you find out what the surge current will be for your Air Cond before buying the inverter? What is the LRA (Lock Rotor Amp) rating of the Air Cond?
 
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Compressor motor will not be happy on modified sine, most electronics don't care.
Sine wave for sure, suggest LF type inverter, but will probably work on HF inverter depending on specs of the AC unit
 
On my RV I want to know if anyone is been running a air conditioning unit on a modified sine wave inverter. The plan is to use a 3000W inverter to be able to run the AC unit for a couple hours a day.
I am trying to decide if I really need to get a pure sine wave inverter or if a modified sine wave will work fine. I know there are issues with electronics on a modified sine but will it bother the AC unit.
If you are shopping price to the point you are looking at modified sine inverters, then don't worry about it. Whatever you end up buying will be very unlikely to be able to start the AC compressor motor in the first place. A soft-start circuit for your air conditioner will cost ~$300. I recommend you put that money into a better inverter (low frequency) instead.

In my opinion, if you are spending less than $700 on a 3000W inverter then you are throwing your money away if your plans also include starting an AC motor with it.

Running AC on an RV's inverter is rich man's game. You will need a lot of solar and batteries to be able to power that for any period of time. A small generator would be much cheaper than an inverter, solar and batteries.

Have you considered getting a portable evaporative cooler? I have one of these on my patio and it work great for one person and ok for two people. They draw 150W AC and use a lot of water. Plus they would be useless in humid climates. Works for me in the desert. A better strategy in my opinion, is to travel to where it isn't hot. That is my plan.

 
I have not tried an AC unit but the things I've run on a modified sine wave inverter have often produced abnormal buzzing sounds and reduced performance.
 
In my opinion, if you are spending less than $700 on a 3000W inverter then you are throwing your money away if your plans also include starting an AC motor with it.

Running AC on an RV's inverter is rich man's game. You will need a lot of solar and batteries to be able to power that for any period of time. A small generator would be much cheaper than an inverter, solar and batteries.

I bought a 2000W pure sine wave inverter for less than $300 and it runs my AC in my truck camper. Granted, I rarely use my AC. If it's hot enough to use the AC, it's time to go where it isn't so hot.

 
If you are shopping price to the point you are looking at modified sine inverters, then don't worry about it. Whatever you end up buying will be very unlikely to be able to start the AC compressor motor in the first place. A soft-start circuit for your air conditioner will cost ~$300. I recommend you put that money into a better inverter (low frequency) instead.

In my opinion, if you are spending less than $700 on a 3000W inverter then you are throwing your money away if your plans also include starting an AC motor with it.

Running AC on an RV's inverter is rich man's game. You will need a lot of solar and batteries to be able to power that for any period of time. A small generator would be much cheaper than an inverter, solar and batteries.

Have you considered getting a portable evaporative cooler? I have one of these on my patio and it work great for one person and ok for two people. They draw 150W AC and use a lot of water. Plus they would be useless in humid climates. Works for me in the desert. A better strategy in my opinion, is to travel to where it isn't hot. That is my plan.

HaldorEE, Thanks for the comments. As for a generator, I really like quiet. As for batteries, I have ~7,500W for less that $1k. A little money, but I would not say that much compared to the overall cost of the RV.
 
No, but EVERYONE around you can.
I've got a 11K Dometic AC unit on top of my little adventure trailer and it's loud inside and out. If you were standing 20ft from it, I don't think you'd be able to hear a little 2000w inverter generator over the sound of the AC unit itself. I know everyone's setup is different and I was mostly just teasing anyway. :)
 
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HaldorEE, Thanks for the comments. As for a generator, I really like quiet. As for batteries, I have ~7,500W for less that $1k. A little money, but I would not say that much compared to the overall cost of the RV.
Are you planning on boondocking with AC? It can be done but takes a lot of solar input.


Check out this discussion. These guys have been living off grid (RV and a sailboat) for 10 years and have a ton of practical experience.


Pay attention to the locked rotor amp draw of your air conditioner. The Wynn's were unable to start the AC compressor motor with a 3000W Magnum inverter. Magnum recommended their 4000W, 24V inverter for running an AC. A $300 soft start reduced the starting current to the point their 3000W inverter worked.

Magnum is a top brand inverter $$$$, and it couldn't start the AC without a soft start add on.

A typical cheap, modified sign inverter will either immediately shut down or worse, let the magic smoke out.

Like I said, solar powered AC is doable, but is very expensive.

A $1300 inverter, $300 soft start, 1KW+ of solar panels anf 10KWH+ of batteries is probably about the cheapest system you could make that would actually work.
 
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Are you planning on boondocking with AC? It can be done but takes a lot of solar input.


Check out this discussion. These guys have been living off grid (RV and a sailboat) for 10 years and have a ton of practical experience.


Pay attention to the locked rotor amp draw of your air conditioner. The Wynn's were unable to start the AC compressor motor with a 3000W Magnum inverter. Magnum recommended their 4000W, 24V inverter for running an AC. A $300 soft start reduced the starting current to the point their 3000W inverter worked.

Magnum is a top brand inverter $$$$, and it couldn't start the AC without a soft start add on.

A typical cheap, modified sign inverter will either immediately shut down or worse, let the magic smoke out.

Like I said, solar powered AC is doable, but is very expensive.

A $1300 inverter, $300 soft start, 1KW+ of solar panels anf 10KWH+ of batteries is probably about the cheapest system you could make that would actually work.
Thanks for link to "gonewiththewynns" about their solar. It is a bit out dated 2016 but has good basic information. It gave me some ideas but honestly I am not sure I will have near as much as an issue as they have. My AC unit will run on a 120VAC 15A outlet plugged into my house on a 50ft extension cord. So I don't think there is really a big issue with suppling the startup current. The unit is a 2020 so hopefully is it a bit more modern than some and does not have a big startup current. All else fails then I will get a soft start of some sort. The ones that are marketed for RVs are really over priced (200-300%). Soft starts have been around for 50 years so there are many option if you look outside of the RV market.
Measuring my AC unit with a power meter it only takes 1200W running so I am assuming that a 3000W inverter with a 5000W peak should handle the startup. If not then I will return the inverter to Amazon and get a different one. The Magnum mentioned above is a hybrid and a expensive one at that. I don't need a hybrid so it will be a lot less. The price is more like $300 - 500 not $1300. Once my batteries come in and it defrosts a bit here (Colorado, it is 19 degrees this morning). I can get to work testing all of it.
 
Thanks for link to "gonewiththewynns" about their solar. It is a bit out dated 2016 but has good basic information. It gave me some ideas but honestly I am not sure I will have near as much as an issue as they have. My AC unit will run on a 120VAC 15A outlet plugged into my house on a 50ft extension cord. So I don't think there is really a big issue with suppling the startup current. The unit is a 2020 so hopefully is it a bit more modern than some and does not have a big startup current. All else fails then I will get a soft start of some sort. The ones that are marketed for RVs are really over priced (200-300%). Soft starts have been around for 50 years so there are many option if you look outside of the RV market.
Measuring my AC unit with a power meter it only takes 1200W running so I am assuming that a 3000W inverter with a 5000W peak should handle the startup. If not then I will return the inverter to Amazon and get a different one. The Magnum mentioned above is a hybrid and a expensive one at that. I don't need a hybrid so it will be a lot less. The price is more like $300 - 500 not $1300. Once my batteries come in and it defrosts a bit here (Colorado, it is 19 degrees this morning). I can get to work testing all of it.
If the AC is inverter based then no problem. If not, look up the locked rotor rating of the compressor motor. Then compare that number with the surge rating of your system.

Magnum is a top tier inverter. And nothing new has happened since to improve surge performance. Fancier user interfaces don't make the muscles of the thing any stronger.
 
On my RV I want to know if anyone is been running a air conditioning unit on a modified sine wave inverter. The plan is to use a 3000W inverter to be able to run the AC unit for a couple hours a day.
I am trying to decide if I really need to get a pure sine wave inverter or if a modified sine wave will work fine. I know there are issues with electronics on a modified sine but will it bother the AC unit.
To answer your question, yes, I run our new Rockwood 2205's air conditioner with a 4000-peak/3000-continuous modified sine wave inverter with two 100ah lifepo4 batteries. In fact, it's running in the driveway right now. I've had my inverter for over 30 years and it just keeps on working. If it dies, I'll get a pure wine wave but until then I'll keep using this old dog. It's powered the A/C on our last four campers.
I'm planning on camping at Airventure '21 in Oskosh (medical issues permitting), so I'm going to add two more 100ah lifepo4 batteries. Also two more 200-watt solar panels for a total of 800 watts on the roof and an MPPT controller.
I also have a 3500-watt multi-fueled generator, as I plan on being in the "daytime generator" section of the Scholler campground at Oshkosh.
For the folks that read this and think "jeepers, just run the generator", this will be our last camper (above-mentioned medical issues) so I'm having fun while I can, playing with solar, lifepo4 and inverters.
I agree with everyone that recommend buying a pure sine wave inverter rather than buying a modified sine wave unit just because it's less expensive. In my case, I'm using my 30+ year old, heavy and gigantic old one.
 
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