Solar Panel system making high pitched noise

[sidraja999]

Hello,

I just installed a 9 panel 400v ground mounted solar panel string to my solar setup. When the sun is shining brightly, I notice a high pitched squealing noise coming from the solar panels. It seems to be coming from multiple places....not just one panel. I cannot tell for sure exactly where it is coming from but it not just from one solar panel. The sound is sometimes continuous and sometimes it is just on-off-on-off with no pattern.

This only happens during high voltage when the sunlight is hitting the panels directly. I also noticed the noise (a bit less sound) inside the DC disconnect box which is not near the panels.

The other 2 MPPT strings never produced any noise but they did not operate at such high voltage.

I am using Tigo optimizers under each solar panel.

Sound recording 1
Sound recording 2

Also, I notice that my energy monitor inside my electrical panel shows wild fluctuation in the incoming AC power from the inverter during high producing times. Attached are photos from the graph showing the fluctuation.

Please let me know if you know the cause of this noise.

Thanks for your help!

 

[crossy]

I can't access your recordings; you need to make them public.

Anyway, it's possible you are hearing the switching frequency of the optimisers, either the cores or even the semiconductors. This would tie in with the noise being more prevalent when the system is working hard.

Many young(er) people can hear these supposedly "out of hearing range" frequencies, it's how the ultrasonic "teenager repellers" work.

Do you have a dog, he may be going crazy!

 

[AntronX]

upload recordings to youtube
those emporia charts look bad, something is wrong.

 

[zanydroid]

SMPS coil whine in the optimizers is very plausible.

What inverter is this?

Does the output look clipped/less than you expect?

Is there shading?

Do you have CCA/TAP?

 

[zanydroid]

Regarding the ugly graph, I don’t think the short time scale behavior of TIGO is well understood on this forum so should temper expectations on how deep we can figure out the rabbit hole.

TIGOs are $40 400 W power converters so as long as they have good conversion efficiency and don’t kill themselves that’s probably the most to expect

 

[AZ Solar Junkie]

Regarding the ugly graph, I don’t think the short time scale behavior of TIGO is well understood on this forum so should temper expectations on how deep we can figure out the rabbit hole.

TIGOs are $40 400 W power converters so as long as they have good conversion efficiency and don’t kill themselves that’s probably the most to expect

Minor correction - Tigo switched their optimizers several years ago to 700 watt capacity.

 

[sidraja999]

I have made the sound recording links public. You should be able to access now.

 

[sidraja999]

I can't access your recordings; you need to make them public.

Anyway, it's possible you are hearing the switching frequency of the optimisers, either the cores or even the semiconductors. This would tie in with the noise being more prevalent when the system is working hard.

Many young(er) people can hear these supposedly "out of hearing range" frequencies, it's how the ultrasonic "teenager repellers" work.

Do you have a dog, he may be going crazy!

I also hear the same noise (a little more faint) in the DC disconnect box which is not even near the panels.

 

[sidraja999]

upload recordings to youtube
those emporia charts look bad, something is wrong.

I have made the recordings public.

The charts only become erratic when the sun shines brightly and the panels ramp up production.

 

[zanydroid]

I also hear the same noise (a little more faint) in the DC disconnect box which is not even near the panels.

The high frequency current changes will still make it out there. Dunno if this can indicate an issue with crimp or terminal tightness. Torqued to standard and correct MC4 crimper used? (Can be $40 one, just use the correct size / not yolo with pliers)

Have you considered bypassing the optimizers to see what the inverter behavior is? How many solar panels of work would this be? What is the level of criticality of the optimizers in your array design?

EDIT: I see now it is 9. OK. Doesn’t sound like that much.

Which inverter/MPPT? That is the starting point to try to understand the output pulsing.

 

[sidraja999]

SMPS coil whine in the optimizers is very plausible.

What inverter is this?

Does the output look clipped/less than you expect?

Is there shading?

Do you have CCA/TAP?

Growatt MIN 7600TL-XH-US

It seems that it gets clipped once the solar panels ramp up production. Attached is a graph from today's production from the inverter. Today was a completely sunny day. No clouds.

Yes, there is shading on some panels. The front part of the building casts a shadow on some panels in early morning. There is also a tree that casts a shadow on a corner panel in the early morning.

I have a Tigo CCA and use Tigo TS4-A-O optimizers.

 

[AntronX]

Post pictures of pv wire connections into inverter, dc disconnect, panel wiring. Does the inverter report any errors?

 

[zanydroid]

Listened to the audio recordings. How much did you normalize it/do you think regular playback volume is representative of reality

Because that elicits an “oh shit” level of kneejerk concern from me if it’s realistic.

The MPPT also does pulsing since it is itself a SMPS (so does the inverter… it’s SMPS all the way down)

 

[sidraja999]

The high frequency current changes will still make it out there. Dunno if this can indicate an issue with crimp or terminal tightness. Torqued to standard and correct MC4 crimper used? (Can be $40 one, just use the correct size / not yolo with pliers)

Have you considered bypassing the optimizers to see what the inverter behavior is? How many solar panels of work would this be? What is the level of criticality of the optimizers in your array design?

EDIT: I see now it is 9. OK. Doesn’t sound like that much.

Which inverter/MPPT? That is the starting point to try to understand the output pulsing.

Yes. I used correct MC4 crimp tool.

Growatt MIN 7600TL-XH-US. It has 3 MPPT inputs.

I don't hear the noise during low production. Only when the sun is directly above.

I also hear a similar noise in the DC disconnect box that is far away from the panels.

 

[zanydroid]

I’m not familiar with what’s possible on CCA wrt controlling the TIGOs. Is there an off chance they can be configured to behave as pass through only?

 

[sidraja999]

Post pictures of pv wire connections into inverter, dc disconnect, panel wiring. Does the inverter report any errors?

No errors in inverter today. Attached is the DC disconnect wiring.

 

[AntronX]

Do you have any lightning surge protectors on PV line? OK i see them. What model number are those surge arresters?

 

[sidraja999]

Listened to the audio recordings. How much did you normalize it/do you think regular playback volume is representative of reality

Because that elicits an “oh shit” level of kneejerk concern from me if it’s realistic.

The MPPT also does pulsing since it is itself a SMPS (so does the inverter… it’s SMPS all the way down)

No editing. It is just like it sounds. The sound is from the solar panels.

 

[HighTechLab]

I have Tigos on my ground mount and have never heard them make a noise with a Sol ark 15k. I would suspect your noise is interference coming up the line from the inverter. Likely the 20kHz switching frequency of the inverter.

 

[sidraja999]

Do you have any lightning surge protectors on PV line?

I have a Midnite Solar surge protector for each MPPT in the DC disconnect box. See attached photo.