[RFI] Noise from Generac Solar controllers?

Thu Dec 16 14:38:11 EST 2021

It is correct that the FCC has no regulations specific to the solar industry.  We really don't want them to write any, because FCC has a propensity to relaxing regulations. In Part 15, for example, there is a clause specific to what FCC terms as "appliances." In that provision of the rules, appliances are included in the categorical exemptions for all specific limits,  just like incidental radiators such as brush motors or power lines.  If solar systems were included in the rules, there is always a risk that they would be lumped in the same category.

Under the rules, solar systems are classified as unintional emitters. These do have specific emissions limits that are for the RF noise coupled onto the ac mains below 30 MHz and for radiated emissions above 30 MHz.

ARRL has an information page on the Part 15 rules:

http://www.arrl.org/part-15-radio-frequency-devices

At this point, ARRL has RFI reports involving 3 different solar manufacturers.  Each of them is somewhat responsive to complaints, at least to our staff.  I have some emails from Generac staff and I am going to see what we can do to improve the flow of communication on RFI cases involving their syttems.

Ed Hare, W1RFI
ARRL Lab

-----Original Message-----
From: RFI <rfi-bounces+w1rfi=arrl.org at contesting.com> On Behalf Of Cianciolo, Paul, W1VLF
Sent: Thursday, December 16, 2021 2:14 PM
To: David Eckhardt <davearea51a at gmail.com>; Tony <73guddx at gmail.com>
Cc: Rfi List <rfi at contesting.com>
Subject: Re: [RFI] Noise from Generac Solar controllers?

Dave,

Actually this is not BS...however it is a little deceiving. Check out this PDF on a typical Generac inverter.
https://a1solarstore.com/index.php?dispatch=attachments.getfile&attachment_id=441 

 Scroll down to the section that’s refers to standards compliance quoted here:

"SAFETY: UL 1741 SA, CSA 22.2 #107.1, UL 1998 GRID CONNECTION STANDARDS: IEEE 1547, Rule 21, Rule 14H, CSIP, UL 1741 PCS CRD (Import Only, Export Only)
EMISSIONS: FCC Part 15 Class B"

Here in lies the rub.   Yes they do pass FCC compliance emissions limits for 15 B but 15B does not cover radiated emissions, only conducted emission put onto the power lines.
So yes they do pass.  Does that mean they do not generate RFI,,, Absolutely not. 

There are 2 main noise generating components in a solar power system. Both are tasked with power conversion which for efficiencies sake is done with very fast rise times... and we know what that means. Harmonics.
The 2 components are the "optimizers" and the line inverter.

Solar Edge uses a different topology than Generac however both use "optimizers"  Solar Edge uses 10 optimizer per panel usually at the 300 watt +/- level  20 panels = 20 optimizers. The classic 200 kHz problem

Generac uses a similar but different topology. Several panels to a single optimizer. This means the optimizer is running at the kilowatt level or so.. say 20 panels and 4 optimizers.

All this is happening on the DC side of the solar power system, not subject to the 15B conducted emissions requirements. When you are switching  mult-kilowatt  level power with fast rise times, there is going to be RFI.
BTW Generac systems manifest themselves as having harmonic energy at 39 KHz intervals.  This the switching frequency used in the optimizers.

The line inverter in some topologies can and is another issue... But again, the line or AC side meets conducted emissions.

73,

Paul Cianciolo, W1VLF
ARRL Product Review Test Engineer
Formerly RFI engineer, having dealt with both SE and Generac many times

ARRL - The national association for Amateur Radio™
225 Main Street, Newington, CT 06111-1400 USA
Telephone: (860) 594-0210
FAX: (860) 594-0259
Email: w1vlf at arrl.org
World Wide Web: www.arrl.org

-----Original Message-----
From: RFI <rfi-bounces+pcianciolo=arrl.org at contesting.com> On Behalf Of David Eckhardt
Sent: Thursday, December 16, 2021 1:46 PM
To: Tony <73guddx at gmail.com>
Cc: Rfi List <rfi at contesting.com>
Subject: Re: [RFI] Noise from Generac Solar controllers?

If someone on this lest knows of the FCC regulation(s) addressing the solar industry, please let us all know.  To my knowledge, so far, there is nothing addressing the solar industry.  ARRL, is there anything addressing this RFI source?

Dave - WØLEV

On Thu, Dec 16, 2021 at 6:44 PM David Eckhardt <davearea51a at gmail.com>
wrote:

> QUOTE:  " For what it's worth, I contacted Generac on N1UK's behalf 
> and the gist of the conversation was that their equipment meets all 
> FCC requirements which is the standard answer you'll get from most if 
> not all solar equipment manufacturers. I'm sure you'll get the same 
> answer if you ask your Generac salesmen about RFI."
>
> This is BS as the FCC has no specific regulations for the whole solar 
> industry.
>
> Dave - WØLEV
>
> On Thu, Dec 16, 2021 at 6:31 AM Tony <73guddx at gmail.com> wrote:
>
>> Ken:
>>
>> I know of several hams who are experiencing RFI caused by Generac 
>> home solar. In each case, the interference turned out to be emanating 
>> from a neighbors installation. In one particular case, Mark N1UK, 
>> experienced RFI from a neighbors system located 400 feet from his 
>> home. His neighbor had the system installed mid-summer I believe and 
>> I don't know if the issue was resolved. You can find Mark's contact info on QRZ.
>>
>> Most home solar systems share like-components so they all have the 
>> potential to cause RFI regardless of the brand. At least one company 
>> specifically warns against installing solar panel systems near ham 
>> radio installations and that's SolarEdge. The quote below was taken 
>> from a SolarEdge document titled:  "Installing a SolarEdge System 
>> near an Amateur Radio System".
>>
>> It says in part:
>>
>> "/due to the afore-mentioned factors and to the higher sensitivity 
>> and physical layout of HAM radio equipment, we have seen in the past 
>> installations where the noise level measured by HAM radio operators 
>> was above the urban ambient noise especially, in the 6M band and 
>> lower frequencies, while having a much lower noise level on the 2M band.
>> *Therefore we do not recommend the installation of SolarEdge systems 
>> at sites where HAM radio equipment is installed. * / / / For what 
>> it's worth, I contacted Generac on N1UK's behalf and the gist of the 
>> conversation was that their equipment meets all FCC requirements 
>> which is the standard answer you'll get from most if not all solar 
>> equipment manufacturers. I'm sure you'll get the same answer if you 
>> ask your Generac salesmen about RFI.
>>
>> Best of luck,
>>
>> Tony -K2MO/
>> /
>> /
>> /
>>
>>
>>
>>
>>
>>
>>
>> On 12/16/2021 12:06 AM, Ken Bandy, KJ9B wrote:
>> > Hi all.  I am contemplating having a “PowerHome Solar” power system 
>> > installed at my house, and am a little concerned about possible RF 
>> > noise generation from the system.  This system uses a Generac controller.
>> Does
>> > anyone have any experience with a system using a Generac 
>> > controller?  I
>> know
>> > early inverters were often RF noisy, but I’m hoping that the later
>> models
>> > have addressed noise generation.
>> >
>> > Any input is appreciated.
>> >
>> > 73,
>> > Ken, KJ9B
>> >
>> >
>> > _______________________________________________
>> > RFI mailing list
>> > RFI at contesting.com
>> > http://lists.contesting.com/mailman/listinfo/rfi
>>
>> _______________________________________________
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>
>
> --
> *Dave - WØLEV*
> *Just Let Darwin Work*
>
>

--
*Dave - WØLEV*
*Just Let Darwin Work*
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