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I have a solar power setup with an array of panels running to an inverter, which is connected to a set of batteries and to two other devices for monitoring the net metering, power output, and so on.

When the inverter is receiving power from the panels and is inverting it, there is a 15kHz whine/scream from the inverter. It’s unbearably loud to me and my wife, but 15kHz is high pitched enough many people can’t hear it.

Further – I have 2 appliances from LG that are "smart inverters": a microwave and a washing machine. When the inverter runs, these appliances also emit the exact same 15kHz screech and it’s unbearably loud inside. Other appliances like my computer monitors, cable modem, hue lightbulbs, audio receiver ALSO make the 15kHz noise, but not to the degree of the LG microwave.

We have tried:

  • Disconnecting the batteries such that it’s a simple solar setup
  • Changing settings on the inverter to various power settings per the manufacturer’s advice
  • Adding toroids to the battery cables – this caused a spreading of the 15kHz spike into a more spread out curve from 14kHz to 16kHz, but didn’t really change the ear splitting effect. When we did this, the devices inside also spread out their screech.

The inverter is a Sol-Ark 12kW. I don’t know much about electronics, but here’s a spec sheet: https://www.sol-ark.com/wp-content/uploads/2021/02/12K-Spec-Sheet-2-4-2021.pdf

I’ve read that more economic manufacturing processes will reduce cost in ways that increase noise production. This came up as I read about FCC 15 class B for unintentional radiators. But in reading the specs for the upper sonic range (10kHz-20kHz), I don’t know how to approach measuring to see if my inverter meets the spec. The product itself has been confirmed as compliant with that regulation, so my question is more… Is it something in my house causing this?

Another thing to note: WHILE the washing machine runs, when the motor turns the basin, the noise spikes at 15kHz regardless of the inverter running or not. If I then muffle the sound and put my spectral analysis app on my microwave, I can see the 15kHz pulsing when the motor from the washing machine pulses.

These noises are essentially inaudible if the inverter is not running, but at this point I’m 6+ months into a worthless solar installation that I’m paying for because when it runs I have ringing in my ears 24/7 and nonstop headaches.

From an electronics standpoint – does anything stand out? Am I overlooking something? Is there a standard way to get electricians/installers to take this seriously if they themselves can’t hear the noise?