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Re: [RFI] Covering Solar Panels To Assess RFI

To: "Rfi List" <rfi@contesting.com>
Subject: Re: [RFI] Covering Solar Panels To Assess RFI
From: WW3S <ww3s@zoominternet.net>
Reply-to: WW3S <ww3s@zoominternet.net>
Date: Thu, 27 Aug 2020 01:10:34 +0000
List-post: <mailto:rfi@contesting.com>
There was a good conversation about this a year or so ago on this reflector. As I recall, the system generated interference with the panels disconnected. Seems like certain panel manufacturers were suspect, possible impurities during the manufacturing process. I believe Solar Edge themselves helped identify the suspect panels.

------ Original Message ------
From: "Hare, Ed W1RFI" <w1rfi@arrl.org>
To: "Tony Brock-Fisher" <barockteer@aol.com>; "Tony" <dxdx@optonline.net>; "Rfi List" <rfi@contesting.com>; "Gruber, Mike W1MG" <mgruber@arrl.org>; "Cianciolo, Paul, W1VLF" <pcianciolo@arrl.org>
Sent: 8/26/2020 9:27:57 AM
Subject: Re: [RFI] Covering Solar Panels To Assess RFI

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.


-----Original Message-----
From: Tony Brock-Fisher <barockteer@aol.com>
Sent: Wednesday, August 26, 2020 6:54 AM
To: Tony <dxdx@optonline.net>; Rfi List <rfi@contesting.com>; Hare, Ed W1RFI 
<w1rfi@arrl.org>; Gruber, Mike W1MG <mgruber@arrl.org>; 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 


-Tony, K1KP

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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