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Powerwalls + Air Conditioning

nwdiver

Well-Known Member
Feb 17, 2013
7,432
9,442
United States
Oh I have looked into it, I got a few quotes to re-do the house with mini splits or a more efficient conventional setup.

The quotes ranged from $18k - $24k not anywhere remotely in the cards right now. Especially considering the current AC setup works great, it just draws a lot of power.

I've got a LG 2 ton 3 split unit at my house. I LOVE, LOVE... LOVE IT! The VFD is like magic. I have a 4kW Magnum off-grid inverter that can surge to 8kW. Surge absolutely NOT needed :) When I'm running off-grid the refrigerator cycling causes a much larger surge then when the AC cycles. It's frustrating that VFDs aren't more common... they're amazing!

On top of that it's a mini-split so I can cool one room at a time. Running a 12k BTU unit to heat or cool my living room uses <1kW! :)

If you're decent at DIY split systems are not difficult. I've installed 4 systems, all doing fine.

Another option is instead of the soft-start which appears to just be a larger capacitor bank... install a VFD controller.
 

NuShrike

Member
Nov 13, 2017
459
193
SoCal
Another option is instead of the soft-start which appears to just be a larger capacitor bank... install a VFD controller.
I believe the soft-starter IS a VFD controller as it's just a small box. No giant caps such as a hard-starter.

Is there another VFD controller you know of?
 

nwdiver

Well-Known Member
Feb 17, 2013
7,432
9,442
United States
I believe the soft-starter IS a VFD controller as it's just a small box. No giant caps such as a hard-starter.

Is there another VFD controller you know of?

Doesn't look like it. Current still surges... just lower than without it. There is ZERO surge with a VFD. With a VFD, the motor speed is slowly increased by raising frequency in a controlled way. It's not on or off. A VFD would be a slow increase from 0 to ~18A not a sudden jump to ~30A and a slow decrease to ~18A.

Running off-grid I've watched current increase through my Magnum Inverter when the HVAC kicks on. It's like when your car starts charging. It doesn't jump to the charge rate... it's a very gradual increase. The time from start to full power is measured in seconds not milliseconds.

Screen Shot 2018-09-29 at 11.44.39 AM.png

There are lots of VFDs available. The trick is figuring out a way to integrate it.

Systems designed for a VFD are obviously best. Another reason I love my mini-split is that they generally don't cycle. Most HVAC cycles on/off to maintain temperature. Mine just runs more slowly. Sometimes it's running so slow you can't even hear it standing right next to the outdoor unit.

My next upgrade is going to be a refrigerator with a VFD... :)
 
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