Sol-Ark 15k -> inverter microwave 15kHz noise solved

[reardencode]

Hopefully this helps some of the folks who have reported 15kHz noise problems with their Sol-Ark (/Deye/SunSynk) inverters. I've had mine running for about a month now, and it's located in the garage directly below my pantry (where the microwave is located). My wife and kids have been reporting a bothersome 15kHz noise in that area since it was powered on, and I was expecting to need to install sound proofing on the garage to block sound transmission into the living space. After some investigation however, we discovered that the noise is loudest inside the microwave. This indicated that it's not a matter of sound transmission but electrical conduction or resonance.

I found this post where Wiggly Electron shows a 50-turn iron core inductor he built to solve similar noise with his installation. I'm happy to report that my much easier to build solution also stopped the noise as well.

I bought some MnZn toroids and THHN, and made an inductor with 10 turns (10 passes through the center of the toroid) yielding 1.2-1.7mH of inductance.

I installed it in series between the microwave's circuit breaker and its hot line, and got a 40dB reduction in 15kHz noise within the microwave.

Obviously this will not solve the 15kHz noise problem where it's emanating directly from the inverter, but hopefully it helps some folks. Any appliance with a switching power supply could have a similar problem, so you may need to hunt down the noise culprit and add multiple inductors.

The only downside I'm aware of to this approach is that it shifts the power factor on that circuit toward the inductive (about 1%, I think); shouldn't be a problem.

 

[robby]

I tried a low pass filter on the Power lines going to my Ham Radio and No change. The Antenna is picking up the noise directly from the Inverter. I pointed the beam away from the electrical room and the noise was gone. If I point it at any other angle it comes back and is at its worst when the antenna is pointed in the direction of the electrical room.

 

[reardencode]

I tried a low pass filter on the Power lines going to my Ham Radio and No change. The Antenna is picking up the noise directly from the Inverter. I pointed the beam away from the electrical room and the noise was gone. If I point it at any other angle it comes back and is at its worst when the antenna is pointed in the direction of the electrical room.

Radiated RF is a totally different issue that I haven't started working on yet. Could be from the inverter itself, or more likely a resonant length of wire attached to it. Some common mode choking via ferrites may help, but finding exactly which wire is the problem will be a project.

 

[robby]

Radiated RF is a totally different issue that I haven't started working on yet. Could be from the inverter itself, or more likely a resonant length of wire attached to it. Some common mode choking via ferrites may help, but finding exactly which wire is the problem will be a project.

It’s it related to the MPPTs. The more power being produced the more QRN. If I switch off the PV it’s gone.
In the early morning and evenings it gets lower and lower until it’s gone just before Sunset.
The motivation dilemma for me is that the bands are typical at their worst during peak sun hours so getting this fixed is on the back burner for now.
Dylan at Sol-Ark thinks toroids wound for 15Khz put on the battery cables may solve the issue.

 

[Shawn Hayes]

Hopefully this helps some of the folks who have reported 15kHz noise problems with their Sol-Ark (/Deye/SunSynk) inverters. I've had mine running for about a month now, and it's located in the garage directly below my pantry (where the microwave is located). My wife and kids have been reporting a bothersome 15kHz noise in that area since it was powered on, and I was expecting to need to install sound proofing on the garage to block sound transmission into the living space. After some investigation however, we discovered that the noise is loudest inside the microwave. This indicated that it's not a matter of sound transmission but electrical conduction or resonance.

I found this post where Wiggly Electron shows a 50-turn iron core inductor he built to solve similar noise with his installation. I'm happy to report that my much easier to build solution also stopped the noise as well.

I bought some MnZn toroids and THHN, and made an inductor with 10 turns (10 passes through the center of the toroid) yielding 1.2-1.7mH of inductance.
View attachment 167714
I installed it in series between the microwave's circuit breaker and its hot line, and got a 40dB reduction in 15kHz noise within the microwave.
View attachment 167710View attachment 167711
Obviously this will not solve the 15kHz noise problem where it's emanating directly from the inverter, but hopefully it helps some folks. Any appliance with a switching power supply could have a similar problem, so you may need to hunt down the noise culprit and add multiple inductors.

The only downside I'm aware of to this approach is that it shifts the power factor on that circuit toward the inductive (about 1%, I think); shouldn't be a problem.

Two weeks ago I visited with engineeer775 (YouTube) at his shop. We had an extensive conversation about equipment and a few issues. He described a very similar issue he had with a 15K install for a customer. He claimed it was a very high pitched noise (whine) with certain appliances. I don’t recall all of the conversation, nor did I get any details .
He claimed he work with Sol-Ark and they apparently made an adjustment to the either software or hertz (KHz) somehow. He said it reduced or totally eliminated the noise.
I can not speak intelligently on this, but it may be possible to reach out to Sol-Ark or engineer775 directly to discuss for a better solution? Ironic you post this right after we had this conversation….

 

[reardencode]

Two weeks ago I visited with engineeer775 (YouTube) at his shop. We had an extensive conversation about equipment and a few issues. He described a very similar issue he had with a 15K install for a customer. He claim it was a very high pitched noise (whine) with certain appliances. I don’t recall all of the conversation, nor did I get any details .
He claimed he work with Sol-Ark and they apparently made an adjustment to the either software or hertz (KHz) somehow. He said it reduced or totally eliminated the noise.
I can not speak intelligently on this, but it may be possible to reach out to Sol-Ark or engineer775 directly to discuss for a better solution? Ironic you post this right after we had this conversation….

Nice! On the other forum I linked, some folks got a software update with a "low noise mode" for their SunSynks. I suspect that mode has some other trade-off, so prefer my solution of filtering the one problem circuit.

 

[reardencode]

It’s it related to the MPPTs. The more power being produced the more QRN. If I switch off the PV it’s gone.
In the early morning and evenings it gets lower and lower until it’s gone just before Sunset.
The motivation dilemma for me is that the bands are typical at their worst during peak sun hours so getting this fixed is on the back burner for now.
Dylan at Sol-Ark thinks toroids wound for 15Khz put on the battery cables may solve the issue.

Hmm, what band is your QRN on? Others have reported 20m/15MHz, in which case I'd expect the radiator to be on the lines to the roof (battery cables should be way too short). Some snap-on ferrites with 1-2 turns on the solar panel wires might reduce it. I put some on those lines prophylactically.

You're making me want to get my radio and antennas setup!

 

[robby]

Hmm, what band is your QRN on? Others have reported 20m/15MHz, in which case I'd expect the radiator to be on the lines to the roof (battery cables should be way too short). Some snap-on ferrites with 1-2 turns on the solar panel wires might reduce it. I put some on those lines prophylactically.

You're making me want to get my radio and antennas setup!

I have the problems on 10m-40m with the exception of 17m for some unknown reason.
Snap on ferrite are probably not going to do anything. You really need the Ferrite Rings that can hold this size wire and the turns needed.

 

[reardencode]

A single turn through something like this will put 100 ohms or so of impedance at the frequencies of concern. Potentially sufficient.