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

PopDBop

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Once you figure this out, you can sell your findings to Midea.
Ha! Doubt it. Companies rarely take outside input from the public for a number of reasons, including liability and IP rights problems. Now, since this thing is probably designed and produced in Ch*na, they'd be happy to steal it and make it their own. lol
 

rcrracer

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Got it. I just assumed that the LG was an inverter model.

Well, with the difference in PF's, total energy wise, yeah, could be on par with the inverter AC's. However, I chose the inverter AC Midea for the 'soft' starting and better management of power while running. Also, it is considerably more quiet than other window shakers. I suppose once I get a o-scope I can consider PF correcting the Midea. Would be nice if the had gotten back to you. I wonder who, if anyone, will lead the way in PF correcting these inverter units. I'd give it a shot. Just need to wait until I get my test gear in and configured first.
If you can get a cap to PF correct at a particular range of wattage without serious repercussions, I believe I know how to PF correct over the entire range of wattage.
 

PopDBop

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Clever way to test for correct (close to correct) PF correction capacitor value. And the OP's rule of thumb (He's from the UK, if you can't tell from the spellings):

Simpler formulae; if you want to do PFC but know only that your load is heavily inductive (i.e. PF = 0.6 or lower), then the following approximations hold good within about ten percent:
* At 115V/60Hz, the capacitor (in microfarads) is 20.76 times the load current (in Amps).
* At 230V/50Hz, the capacitor (in microfarads) is 12.46 times the load current (in Amps).


 

Big Matt

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I have had this problem with my 12 volt 3000 watt Victron inverter as well as my Growatt 48 volt 3000 watt inverter. I decided to put my lights on a different inverter to save my sanity. I thought this problem would be resolved by installing a mini split but it seem to hum at a different frequency and my lights flicker at different rates now. Really its the same problem. I don't think its the inverter but I could be wrong.
 

Ron34422

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I have had this problem with my 12 volt 3000 watt Victron inverter as well as my Growatt 48 volt 3000 watt inverter. I decided to put my lights on a different inverter to save my sanity. I thought this problem would be resolved by installing a mini split but it seem to hum at a different frequency and my lights flicker at different rates now. Really its the same problem. I don't think its the inverter but I could be wrong.
Thanks for your reply...I have tried 3 different inverters with the same results...different rates of fluttering with different inverters ...thanks for the heads up on the mini split because I thinking in that direction...seems like the Midea inverter/compressor technology doesn't work with inverters so well...
 

NOLA_Castle

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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.
PopDbop, from your experience, do you think 12V - 1000/2000Watt inverter can run/start up Midea 8k btu unit?
 

Ron34422

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PopDbop, from your experience, do you think 12V - 1000/2000Watt inverter can run/start up Midea 8k btu unit?
I've started and run the Media 8k with a 500W Victron...3000W Growatt, and another 3000W inverter...the issue I'm having is the light fixtures (LED bulbs) fluttering when connected to the inverter also while the Midea compressor is running...
 

NOLA_Castle

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I've started and run the Media 8k with a 500W Victron...3000W Growatt, and another 3000W inverter...the issue I'm having is the light fixtures (LED bulbs) fluttering when connected to the inverter also while the Midea compressor is running...
But the Midea 8k btu ran (with or w/o compressor running) no issue right?
 

Ron34422

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Where would one put this? In line with the midea unit or in line with the lights? Or possibly before it gets to the power distribution panel?
I’m willing to give it a go.
I' going to try one inline as close to the Midea AC as possible...I'll let you know if it works...I tried and it did not work...lights still fluttering
 
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Big Matt

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I' going to try one inline as close to the Midea AC as possible...I'll let you know if it works...I tried and it did not work...lights still fluttering
Ok, I tried this filter from Amazon https://www.amazon.com/dp/B073MCGBP5?psc=1&ref=ppx_yo2_dt_b_product_details and it made a pretty good difference but I'm still dealing with the flicker. I'm thinking about adding another filter in line. I have no idea if it will work but I think its worth another $15 try.
I also noticed when my air conditioner gets into a lower power mode it causes the inverter to register between 20% load and a 10% load that is a harmonic of 10% of the inverter capacity that is bouncing and causing a flicker. That was reduced by about 3% to 4%. will one or 2 more filters smooth out the bumps? I have no idea. I'm willing to throw a little bit of money at it before I throw a lot of money at a new inverter.
 

schmism

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Where would one put this? In line with the midea unit or in line with the lights? Or possibly before it gets to the power distribution panel?
I’m willing to give it a go.
RF interference is not the same as inductance (power factor) that opposes the change in phase of the AC power
 

Big Matt

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RF interference is not the same as inductance (power factor) that opposes the change in phase of the AC power
I’m cool with that and honestly clueless on a solution. Even a fool gets lucky sometimes.
Any ideas would be helpful.

Thanks!
 

rcrracer

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I’m cool with that and honestly clueless on a solution. Even a fool gets lucky sometimes.
Any ideas would be helpful.

Thanks!
I'm the person who suggested the $15 solution. Thanks for the results posting. Too bad you can't quantify how much it improved your situation.
Throw another $15 or maybe a 3 phase reactor at your problem? https://www.ebay.com/sch/i.html?_fr...Primary%20Current%20Rating=8%20A&_dcat=260831 Use one outside coil for the line wire and the other outside coil for the neutral wire along with your $15 box. What's bad with doing this is the power factor will probably be reduced. Then capacitor(s) need to be added to bring the power factor back closer to unity possibly leading to more harmonics and lights flickering. Because the Midea inverter presents a constantly changing situation, the sizes of the reactor(s) and the capacitor(s) need to be constantly changing. (I think this is all correct. Possibly none of it is correct. This is something an industrial electrician or electrical engineer might know about. I am neither.)
 

eXodus

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Thanks for your reply...I have tried 3 different inverters with the same results...different rates of fluttering with different inverters ...thanks for the heads up on the mini split because I thinking in that direction...seems like the Midea inverter/compressor technology doesn't work with inverters so well...

I have two Midea U inverters 8k and 12k - and both don't have that issue you are describing. You should consider that your Midea is somewhat defective.

I got two shipped which I returned because they jammed the wifi and powerline network as soon as I connected them to the power (even without turning on)
 

MrM1

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So is this light issue happening with any inverter compressor AC? Would a mini split suffer from the same issues?

Has anyone tested to see if light flickering is just LED lights, or is it filament lights too (like any ones actually uses those any more but I still have a bulb or 2 laying)
 

eXodus

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So is this light issue happening with any inverter compressor AC? Would a mini split suffer from the same issues?

Has anyone tested to see if light flickering is just LED lights, or is it filament lights too (like any ones actually uses those any more but I still have a bulb or 2 laying)
no it doesn't. It's probably a combination of a cheap LED light power supply inside the bulbs and less then optimal working control board of the Inverter Unit.

A good LED power supply would not let any ripples through to LEDs. They were probably where too cheap to add a 5 cents capacitor at the output.
Same probably true for the Inverter A/C board - when it would be correct designed it should have no back-feed. But also probably cheap built here.
Further the Growatt is a High Frequency Inverter - which is not able to smooth out small ripples. Only Low Frequency Transformer based Inverter can do that.

Thanks for your reply...I have tried 3 different inverters with the same results...different rates of fluttering with different inverters

I wonder why you would even use 120V AC for LEDs - just connect them to your batteries on DC?

So you got 3 choices here:
- Move to DC LEDs or high quality AC LED bulbs (the ones from the dollar store flicker on the regular grid)
- Switch out the Midea
- Switch to a Low Frequency inverter
 
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MrM1

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Thanks. Low Frequency is all I needed to know. I'm building out the Growatt 12kw which is a low frequency version so we should be OK
 
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