High pitched noise from enphase solar and battery system - need advice on eliminating

Ouch! Not a cooling fan issue like something stuck in the fan box / baffle? I know when our system went live to the grid, and suddenly there was a rush of power through the inverter, the cooling fans kicked on with a bit of a roar. The fans kick on every now and then, but it's not as intrusive like you are experiencing.

I hope you are able to get your installer to button everything down!

I don't own Enphase equipment, but might be able to help you with your system issues using troubleshooting logic. Since your installer has been back to your Enphase system 8 times over the past 4 weeks, the low hanging fruit has already been picked. i.e. what worked on the other 99 systems they installed has already been tried and has not fixed your problem. You describe a problem above, but that might mean something totally different to somebody else. You gave us some data, but not enough to help solve your problem.

Exactly what is the problem? A lot of the questions people would ask to clarify your system are on your system schematic. If you can, share a dumbed down version of the schematic without personal information. A schematic clears up a lot of misunderstandings. You state some of the equipment installed and most people would assume it is installed in a certain way, but maybe your installer used a different method. Otherwise a complete list of equipment is helpful.

Noise can be very subjective. What is bothersome to you might be OK with me. What you do know, it that the noise level was OK before the solar install. Just so we know the extent of the noise problem, write down the issue in a problem statement. This is the thing we will try to solve.

• i.e. When I am sleeping, I can hear a high pitched noise from the wall that is located 10 feet away from main electrical panel. This noise happens every night.

In the mean time, you had solar, a battery, combiner/communications module and a new main electrical panel installed as far as I know. Enphase power line communications runs at 110khz while line power as you know is at 60hz. In the past, I have only used industrial grade equipment, but some of the free apps (or not free apps) available might be able to point you in the right direction.

I think what you need is a spectrum analyzer. I'm not sure how good an iphone spectrum analyzer is, but it might be good enough to compare different scenarios.

Scenario 1: Baseline. Turn off everything. even your main breaker. Go to your bedroom and see if the noise exists. Take a frequency spectrum snapshot at a known location and direction.

If no noise, then go to next step.

Scenario 2: Start turning on breakers, but not the enphase equipment. Turn one on, go to your bedroom check for noise. No noise, turn on next breaker. Repeat. Take a frequency spectrum snapshot at a known location and direction.

If no noise, then go to next step.

Scenario 3: turn on Enphase battery. Is it possible to only turn on the Enphase battery without solar? Or turn on Enphase equipment but turn off Enphase solar breakers? This is because your problem happens at night. Take a frequency spectrum snapshot at a known location and direction.

If no noise, then turn on everything and take a frequency spectrum snapshot at a known location and direction.

In addition to what I wrote above, I was trying to say since line frequency is 60 hz and enphase is 110khz (something out of hearing range), there might be some harmonic of 60 hz that is causing the problem. A spectrum analyzer would pinpoint the frequency.

I should have checked support.enphase first. This buzzing isn’t a one off problem. Search “Why is there a buzzing noise when unused power goes back to the grid?” With EE’s, utility people,and enphase “working” on the issue, this is officially out of my wheelhouse. Good luck!

A really simple diagnostic "tool" is a cardboard tube like a paper towel tube. Put it on your ear and move it around the components. The tube focuses the noise to tighten the location where the noise is coming from..

The other non electronic thing to consider is how is the equipment mounted?. Electronics can cause vibration and if mounted on steel panel it can cause a buzz. Sometimes it is as simple as changing the mounting point or using vibration insulating mounts.

I find if I can figure out where the noise is coming from, I can rig up noise reduction enclosures. Noise acts like light, so think of the noise source as having a light bulb mounted on it, the trick with an enclosure is to keep air ventilation but get rid of line of sight with the light bulb and that means lots of corners in the enclosure and sound absorbing foam on the surfaces to keep if from bouncing off the flat surfaces. Dense silicon foam works pretty well for high frequencies. I used to have to deal with very noise gas compressors in residential areas and paid a lot of money for sound absorbing enclosures and it all came down to sound absorbing surfaces and corners. More than once someone added a vent in the enclosure after the design and it would become a bit source of noise, we would end up adding a steel plate on standoffs that covered the grill opening and covered the grilled side with silicon foam.