[RFI] SolarEdge RFI Inverter On/Off Test

[r55stan at gmail.com]

Another inverter brand I found to be absolutely quiet is Fronius (also German made).  That is the brand of inverter I have for the solar power system I have at my house.  Just after I had it installed, I checked every band with a SDR (connected to my station antennas) to see if any signals stopped when I shut it off.  I found nothing.  I know all inverters use switching to do their thing and was curious what frequency my Fronius uses.  Standing near it in the garage with the SDR heard nothing.  Finally, I draped a wire as the SDR antenna over the inverter and found very weak signals at 20 kHz intervals.  Compare that to SolarEdge systems that a portable radio picks up at 700 feet.

Randy KQ6RS

-----Original Message-----
From: RFI <rfi-bounces+r55stan=gmail.com at contesting.com> On Behalf Of Kim Elmore
Sent: Wednesday, February 5, 2020 7:58 AM
To: Tony <dxdx at optonline.net>
Cc: Hare, Ed W1RFI <w1rfi at arrl.org>; Rfi List <rfi at contesting.com>
Subject: Re: [RFI] SolarEdge RFI Inverter On/Off Test

All of this has been VERY informative. My wife suggested we look into a photovoltaic system for our house, and I find the idea very compelling. But I won’t do it at the cost of my Amateur Radio activities. I may talk to some locals, but any system will have to not merely RF quiet, but absolutely RF *silent* from DC to as high as I can collect the equipment to measure. 

Kim N5OP

"People that make music together cannot be enemies, at least as long as the music lasts." -- Paul Hindemith

> On Feb 5, 2020, at 1:59 AM, Tony <dxdx at optonline.net> wrote:
> 
> All:
> 
> My neighbor gave me permission to shut off his SolarEdge solar panel inverter while I ran some tests. I recorded the results at my home station and noticed that the S-9 spikes disappeared when the inverter was turned off. The noise floor also dropped considerably.
> 
> A few remaining spikes were tracked to the cabling that feeds the solar panel optimizers which were still running in safe mode. Unfortunately, there's no way to shut off the optimizers without physically disconnecting them.
> 
> The noise reappeared when the inverter was turned back on.
> 
> Before I left, I decided to probe the AC lines running off the house main panel for RFI. Sure enough, there were high levels of the same noise on the the exposed lines that run along the basement ceiling of my neighbors home. All that noise is feeding into the AC lines so the house wiring makes for one big antenna.
> 
> Less significant, but worth mentioning is that the inverter does not have a dedicated ground rod. It's grounded instead to a water pipe in the basement which then splits to the main panel with a 6 foot ground wire.
> 
> I also noted the model number of the inverter and found that it's the same 6KW unit that Tony Brock-Fisher found to be very noisy.
> 
> More to come.
> 
> Tony -K2MO
> 
> 
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