Midea Window AC and Growatt SPF 3000TL LVM-ES...A Bad Combo?

Ron34422

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I installed two of the Midea high efficiency window units a few months ago and they work really well..I recently installed the Growatt SPF 3000TL LVM-ES connecting it to a Connecticut 10 circuit transfer switch panel for my AC output that powers my 10 essential circuits in case of a power failure...The Midea units are connected to two of these circuits along with lights, internet, TV, fridge, etc on the other circuits...I can manually add 1 to 10 of these circuits from grid power to Inverter power and watch how the Growatt functions to take care of the various loads...With all the circuits on Inverter power the max load is around 60% to 75%...The issue I'm having is while either of the Midea compressor units are running the LED light bulbs on all these 10 essential circuits are "fluttering"...some more intense that others to the point you can't stay in the room...When I shut the Midea units down the fluttering and flickering stops...I'm guessing the inverter/compressor that Media is using does not play well with Inverters? Has anyone seen this issue? Any solutions for this problem?
 

rcrracer

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The Mideas have terrible power factors that range from .50 with just the fans on, up to .74 when working hard as they can. It would be great if somebody who owns both a Midea and an oscilloscope, checked out how Mideas effect the sine wave. If Mideas are placed on the two different phases, what will happen?
 

PopDBop

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The Mideas have terrible power factors that range from .50 with just the fans on, up to .74 when working hard as they can. It would be great if somebody who owns both a Midea and an oscilloscope, checked out how Mideas effect the sine wave. If Mideas are placed on the two different phases, what will happen?

Whoa! I'm so glad you pointed out this terrible power factor. I just checked my brand new Midea-U 8000BTU and confirmed the low power factor numbers you posted via my Kill-A-Watt meter (sorry, don't have my oscilloscope yet).

THIS SUCKS! I was all excited that this inverter AC started and ran well on even a dinky 500W inverter and single SLA battery (testing purposes only). It works well enough. But now I see that I'll be wasting my precocious stored battery energy on useless reactive loads with this thing. That's going to require noticeably more battery capacity and PV panels to pay for the energy loss in the AC, which is by far my biggest load for my RV/camper/cabin. 🙄

I don't suppose you have PF numbers for the LG inverter window AC units? I'm trying to find them myself right now. I hope they're better than these numbers. I can't imagine they're any worse than the Midea U. I may have to pick up a LG and sell the Midea on Criagslist to someone who's going to run this on grid power and could care less about power factors.
 

rcrracer

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"I don't suppose you have PF numbers for the LG inverter window AC units?"
I've got a feeling they are all about the same. I also have a LG-lw8019er window AC. It has a power factor of 0.99. Also, its compressor doesn't start until a couple of minutes after the fan motors start.
 

NOLA_Castle

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From my recent experience (hurricane Ida) with Midea AC window U shape, the 8000 btu unit consumed 1180Watt for 7hour (with 12V batt +inverter), brought the temperature down from 87F to 79F and maintained 79F. The room is under 200 sqft. The unit is very quiet.
 

PopDBop

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From my recent experience (hurricane Ida) with Midea AC window U shape, the 8000 btu unit consumed 1180Watt for 7hour (with 12V batt +inverter), brought the temperature down from 87F to 79F and maintained 79F. The room is under 200 sqft. The unit is very quiet.
To clarify, are you saying it consumed 1180 watts over a 7 hour period?
 

NOLA_Castle

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PS: once the AC started, nobody left the room and went to sleep. To minimize, cool air escaped from the room with frequent in and out.
 

PopDBop

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I can't find any info on Midea power factors, or people with similar problems
?? You're not going to *find* power factors on a Midea or any other window AC. Most people have no clue what it even means or why it matters..

I and @rcrracer are reporting what we have actually tested with our power meters. And we are getting the same low power factor readings. What else do you want to find?
 

Ron34422

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From my recent experience (hurricane Ida) with Midea AC window U shape, the 8000 btu unit consumed 1180Watt for 7hour (with 12V batt +inverter), brought the temperature down from 87F to 79F and maintained 79F. The room is under 200 sqft. The unit is very quiet.
My Midea Cools very well on my 48 volt Growatt system...the problem is the fluttering light fixtures on the circuit the Media is on and also other circuits that the Growatt is supplying power to...
 

PopDBop

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FWIW, my MIdeal 8000BTU is working on an TINY ad-hoc system that most folks here would say shouldn't or wouldn't work (including myself): a 1000W BESTEC PSW inverter running off a single 12V EverStart deep cycle WallyWorld cheapo battery. Of course, this probably wouldn't run for hours on end. But, the AC DID start and it DOES run.

The power draw is hard to determine the Kill-A-Watt is reading much higher than the BESTEC inverter's output current (see photo). Either way, the power draw is low.

My problem with the power factor at only about .7 is that even at these modest energy consumption numbers, much energy is being wasted on the reactive load of the AC. Now, if it's just plugged into the grid, it may not be a concern. But when you're planning on operating this out in the boondocks off grid with finite battery storage and solar panels, you don't want to have to burn that energy on loads that do no useful work. I really need a much more efficient designed AC with a power factor closer to 90, if that's doable in these designs.
 

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100 Proof

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I also have a LG-lw8019er window AC. It has a power factor of 0.99. Also, its compressor doesn't start until a couple of minutes after the fan motors start.
What is the steady state current draw of that LG-lw8019er?
 

rcrracer

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What is the steady state current draw of that LG-lw8019er?
650 watts is the highest I've seen. The lowest is around 570 watts when it isn't working very hard. Just a guess, average around 630-640 watts. I first used the LG and then the Midea to cool my 1450 sq. ft. FL house, all grid powered.
ACs annual energy usage can be compared here:
It looks like inverter ACs, even with their crappy power factor, will still use less electricity than non inverter ACs, even if you have that particular model LG, which is the most efficient non inverter AC.
 

rcrracer

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The trick would be to determine what size capacitor is needed .... and it seems like the inductive element might vary depending on what the unit is doing.
I wish somebody with an oscilloscope would try that capacitor idea. Doing that might cause some bad harmonics. If there aren't any problems, I have an idea that can possibly greatly improve the power factor of inverter ACs.
 

PopDBop

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Shouldn't it be possible to at least partially correct the power factor with an appropriately selected capacitor?

e.g.
Of course. But it will take some time, money, and expertise to know how to do it. @Smokin seems to have a simple enough solution. That oscilloscope that @Professor Farnsworth wants to see could be helpful in optimizing the power factor. At least, it would be good to see how much of the power factor loss is harmonics vs phase differences.

5mf 370 volt fan capacitor from an AC condenser fan add it to the circuit, that should fix it. I use them all the time on my 3kw genset,
Just put a wall plug on the cap and plug it in.
5µF is generally enough for these smaller AC units? So, you're suggesting just 'plugging' in the capacitor on the branch circuit the AC is plugged into -- positive lead to hot and negative led to neutral?

Now, with the Mideas we have two fans and motors -- one for the inside evaporator coils, the 2nd for the outside condenser coils -- unlike most window AC's that have a single motor driving both fans. So, would it be beneficial to correct the power factor of the evaporator side and condenser side, which also has the compressor load, independently, if you're really trying to optimize this unit for off-grid solar use?
 
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Ron34422

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5mf 370 volt fan capacitor from an AC condenser fan add it to the circuit, that should fix it. I use them all the time on my 3kw genset,
Just put a wall plug on the cap and plug it in.
Are you referring to the fluttering light problem or the power factor issue?
 
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