I think that it is highly unlikely that the panels themselves are creating
Paul Cianciolo, W1VLF, has a Solar Edge system at his house. He had found the
usual wiring, grounding and optimizer issues present at his QTH, from his own
system. Solar Edge came out and replaced everything but the inverter.
From what Paul can tell, the remaining noise, significantly reduced, is coming
from the inverter. I don't recall whether it was conducted onto the ac mains,
which would be subject to FCC Part 15 and other conducted limits, or conducted
onto the input wiring, which is not subject to specific emissions limits. But
Solar Edge is aware of the issue and is designing upgrades that it believes
should cure the problem. When that is complete, they are going to return to
W1VLF and install the upgraded inverter.
So far, Solar Edge has repaired about 200 systems, almost all successfully, at
its own expense. Paul reported that a crew of two took all day to replace
panels, rewire them and replace the optimizers. If we could see every
manufacturer respond like this, we would be happy.
From: Tony Brock-Fisher <email@example.com>
Sent: Wednesday, August 26, 2020 6:54 AM
To: Tony <firstname.lastname@example.org>; Rfi List <email@example.com>; Hare, Ed W1RFI
<firstname.lastname@example.org>; Gruber, Mike W1MG <email@example.com>; Cianciolo, Paul, W1VLF
Subject: Re: Covering Solar Panels To Assess RFI
Was this experiment conducted with the per-panel optimizers connected to the
panels? This is a critical question.
It appears the conclusion of the experiment is that the panels themselves and
by themselves are generating RFI. I am certain this is incorrect. I suspect the
experiment was conducted with the optimizers connected to the panels, and that
the panels powered up the optimizers and the optimizers are generating the RFI,
which would be entirely consistent with my understanding and experimentation
with a single panel and optimizer. Indeed, a 300W halogen lamp provides
sufficient energy to a single panel to power up an optimizer such that it
generates RFI, the characteristic being harmonics appearing at ~200kHz
intervals through 20m and above.
It is highly unlikely the panels themselves generate RFI without the
optimizers, unless they contain some sort of active circuitry that operates at
RF frequencies. Electrically, they look like a huge diode which is back-biased
by the voltage developed in the presence of sunlight. A solar cell, by itself,
does not generate RF.
As is often the case, a poorly conducted or misunderstood experiment can lead
to an erroneous conclusion, which then leads to a futile course of action
yielding a lack of productive results and further frustration.
I hope you can clear up this discrepancy before many more wheels are uselessly
On 8/25/2020 8:44 PM, Tony wrote:
The the inverter on my neighbors solar panel installation was recently
replaced to reduce the RFI caused by the system. The swap only made a
slight change in the interference.
This left the solar panels as the possible source of RFI so my
neighbor and I conducted a test we've done previously which involves
covering each panel with tarps to see what affect it would have on the
We found that the RFI completely disappeared while the tarps were
blocking the Sun from reaching the panels. The noise returned when we
removed the tarps.
I reported this to SolarEdge and they now believe that the panels are
the cause of the interference. They mentioned 2 other installations
that had this same problem with panels that were manufactured in China
by Hanwha and Trina.
The takeaway is that solar panel systems need to be checked from top
to bottom when checking the system for interference. I'm hoping
SolarEdge will keep this in mind when they address their next RFI case.
We also reported our test results to the company who leases the panels
to my neighbor. No response yet.
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