Midea U 12k power from DC (IT WORKS!!!)

[toddincabo]

No switch yet, still running on AC from 800 watt inverter. Worst case power draw (from grid) was 1200W on hot day and high setting. At low and medium setting there is not a noticeable efficiency difference. Main difference will come from using ~96% efficient DC-DC converter vs. 84% efficient inverter.

Thank you. Could you please clarify the 84%? If you want to easily fill back in those holes you drilled you could use some stick putty like in photo, I do it all the time with the pack that comes with separate green and white sticks.

 

[AntronX]

I meant 84% efficient 48V DC to 120Vac inverter I use to power it from my battery. So far it seems OK keeping condenser outlet tubing dry. But I would not be able to detect slight cooling efficiency loss anyway.

 

[Brucey]

No switch yet, still running on AC from 800 watt inverter. Worst case power draw (from grid) was 1200W on hot day and high setting. At low and medium setting there is not a noticeable efficiency difference. Main difference will come from using ~96% efficient DC-DC converter vs. 84% efficient inverter.

I was thinking of getting a midea to keep the inverters occupied in the summer versus the oil filled heater in the winter. But I take pause when you mention that it really makes your 48/800 noisy with the power factor. I guess I could run it on the high frequency Delta 2 max instead.

 

[toddincabo]

I meant 84% efficient 48V DC to 120Vac inverter I use to power it from my battery. So far it seems OK keeping condenser outlet tubing dry. But I would not be able to detect slight cooling efficiency loss anyway.

OK, thank you very much, I'm looking forward to seeing where you go with this, this is great! I think I have it down from the photos where the cables are soldered, the resistors are attached (existing video screenshot), and the DC voltage range from your posts here. In the end, If you could possibly share a quick YouTube tutorial video for amateurs like me it would be greatly appreciated, especially by the RV crowd. I know I'd share that video. Thanks again and take care.

 

[Vigo]

I was thinking of getting a midea to keep the inverters occupied in the summer versus the oil filled heater in the winter. But I take pause when you mention that it really makes your 48/800 noisy with the power factor. I guess I could run it on the high frequency Delta 2 max instead.

I havent noticed any problem running midea 8k or 12k U units from my Growatts. I would highly recommend these units. If they had a good heat mode id like them better than the 2 actual mini splits i have.

 

[AntronX]

Come on Costco stop tempting me.

 

[Brucey]

Come on Costco stop tempting me.

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I was close to buying one but a bunch of reviews mention it makes a bunch of noises including sqealing on the compressor. I can't tolerate that so ended up ordering an LG "dual inverter" 8000 BTU unit for sons bedroom, he loves things ice cold, and then I can bump up the thermostat for the central air.

https://www.amazon.com/gp/aw/d/B0B4PPM8W9

I did see that the Midea regular rectangular units have an option for heat pump heat that works down to 41 degrees...might get one of those for kitchen window, then can turn off the central AC, and then run that in heat mode during the shoulder season before it drops below 41 and then switch to the oil filled radiators for the colder days and nights.

 

[Brucey]

Come on Costco stop tempting me.

View attachment 213898

Limit 5.... just saying

 

[AntronX]

Limit 5.... just saying

Phone not included. Deal breaker.

 

[AntronX]

bunch of reviews mention it makes a bunch of noises including sqealing on the compressor.

High frequency inverter switching squealing is barely noticeable over outdoor fan noise. They have sound insulating mat around compressor to attenuate it. Other noise was from water getting flung onto condenser coil by the fan. It's not bad either. Can't hear either of those indoor.