[SCCC] Solar Panel RFI

Fri Jan 27 22:50:38 EST 2023

Hello,
Red all messages on topic.  Trying to be brief.  I just installed 20 panels
for 8 kW in October.

I went with Stellar Solar as installer, I also had quote from Baker for
almost same price, but chose Stellar as some other local hams had done
install with them.  System uses Enphase IQ8M microinverters.
Sales guy needed some convincing but eventually they sent their engineer
here to see what I was talking about toroids and he brought sample inverter
and cabling with him and I showed how I wanted toroids to be installed on
each inverter.  Basically 7 snap ins were used 3 on each lead coming from
previous inverter and going to next inverter.  Installing all those AC side
toroids took maybe an hour by me and couple their installers on roof after
cabling that wires inverters together was installed up there.  Before each
panel went to roof I installed one additional larger toroid on leads (PV
wires), both leads going through same toroid 2 times.  I think it is
important to have these panel DC leads go through same core to avoid
saturation of core.  Toroids costed me about $500 and I don't know if they
do anything or not but I have not seen on panadapter or heard on air any
buzz from this system even when pointing my low A3S yagi right at it from
some 60 ft away.  If there would be anything that antenna should pick it up.
K6AR installed also with Stellar couple years ago similar system without any
toroids and he has had no interference from it with also Enphase
microinverters (earlier model).  If you go this route I can perhaps send
couple pictures from exact install I did with toroids.

I'm not aware of any Enphase RFI suppression kit but lead installer on site
here mentioned that he had done similar toroid job before once or twice at
request of customer.  Installers did not seem to have any problem with this
little additional work, problem is more to get through sales guy who does
not want to have any complications to slow down his sales.  In contract with
Stellar there was nothing mentioned about this additional job, it was just
little side task on site here.  Sales guy did know about the plan and was OK
with it after he spoke with his engineer.

Couple other notes:
I believe there is limit on maximum system size one can have and it has to
do with electric service coming to your house and size of main panel.  My
main panel is 200A and I could have installed 22 panels without replacing
whole main panel as well as cabling to pole.  If I would build new house I
would probably put in 400A panel, but it did not make sense in my situation
to change it and especially cabling to pole which would have required to
install larger conduit and cabling and would have involved to dig out
neighbors 2 years old fancy concrete driveway.  Could be done, there is
easement but I think it would not be cheap.

My 12 years old propane powered water heater broke around same time as solar
install was finished in October.  I had already considered replacing it with
electric WH some day but as I was leaving for 7 weeks long CQWW trip I
needed to be fast to get it fixed for wife to have hot water.  So I just did
propane replacement.  But interestingly 2 different electricians told me
that they would not replace it with electric one even with solar at house as
there already was propane gas at water heater location.  They both thought
it was more economical to continue with gas powered WH.  And yes it is my
experience after living here for more than 10 years and having propane WH,
stovetop, whole house airflow heater and dryer all powered by propane it
seems that only whole house furnace is using any significant amount of gas.
I really don't see needle going down from any other consumption.  After we
installed solar we actually purchased small electric space heater for master
BR and use it at night and we hardly warm the house any longer with that
propane whole house heater.  My goal is to get through whole year with one
refill of propane tank and I'm quite sure it is possible with this
minimizing of whole house heating.  But for sure after having solar
installed we will consider swapping some of these appliances to electric as
those fail in the future.  And we are looking into replacing one of the cars
with EV maybe this year.  With little driving we do these days and extra
capacity we put on solar system (maybe 30 % or so to actual consumption) we
should be able to sustain one EV more or less.

Net metering will have annual true up date when account is settled and you
are using unused energy credits from summer towards consumption in winter
when panels don't make so much energy, so sizing of the system is based on
your annual consumption (at least in current NEM 2 scheme).  At annual true
up date one does not get much credit for unused energy during the year, SDGE
will pay you vary little if there are any unused kWhrs, so it does not make
much sense to have too big system.  Also, panels are suppose to degrade
somewhat each year, something to consider when sizing the system.

I'm not sure but I think it will be enough to have your application for NEM
3 in by April and there is still some time to install after that.  But solar
install companies will know details.  I was aware of NEM2->3 change coming
and as I did get system up under NEM 2 I have not really followed where
rules of final NEM3 landed.

I did not install battery.  That is where they try to push everybody with
new NEM3 rules.  It is good to understand that without battery if grid is
down your solar panels are also NOT providing you power even if sun is up.
There must be grid connection for system to work if you don't have system
that also includes battery backup.
73 de Marko N5ZO

-----Original Message-----
From: SCCC <sccc-bounces at contesting.com> On Behalf Of Bruce Horn
Sent: Monday, January 23, 2023 6:13 PM
To: Marty Woll <n6vi at socal.rr.com>
Cc: SCCC Reflector <sccc at contesting.com>
Subject: Re: [SCCC] Solar Panel RFI

As I recall, Enphase offers a RFI suppression kit for its micro inverters.

73 de Bruce, WA7BNM   (bhorn at hornucopia.com)

----- Original Message -----
From: "Marty Woll" <n6vi at socal.rr.com>
To: "N6QQ" <n6qq at msn.com>, "SCCC Reflector" <sccc at contesting.com>
Sent: Monday, January 23, 2023 5:08:01 PM
Subject: Re: [SCCC] Solar Panel RFI

Hi, John.

Avoid Solar Edge inverter and the "optimizers" they put on each panel.  They
are a huge noise source, according to many who9 have tried them or live near
them.  I recommend Enphase micro-inverters.  They're efficient and RF-quiet
(as I can attest from my own installation). The PV panels themselves,
regardless of manufacturer, are generally not a source of RF noise.

As for "all-electric", I would not go that route myself.  Electric cooktops
are a PITA when compared with gas, and electric heating may be even more
costly than gas (unless you're using a heat pump system).  Check the energy
efficiency rating of any electric furnace you're considering, then remember
that you'll be using it most in the winter when there's less sunlight
hitting your PV panels.

For reference, I have 8.5 kW on the roof.  It meets most of our demand in
the summer and adjacent months, but it falls considerably short in the
winter.
A reputable installer can look at your historical and proposed power usage
and help you evaluate how much solar you need and how it will affect your
utility bill.

73,

Marty N6VI

-----Original Message-----
From: SCCC [mailto:sccc-bounces at contesting.com] On Behalf Of JOHN SCHROEDER
Sent: Monday, January 23, 2023 4:38 PM
To: sccc at contesting.com
Subject: [SCCC] Solar Panel RFI

I am thinking about putting up Solar Panels and replacing My old gas air
conditioner with an HVAC system.

Would like your suggestions about the  RFI problem and going to All
electric.

Just got a $358 gas heating bill for January.

73, John -- N6QQn6qq

https://www.qrz.com/db/n6qq

ARRL and CQ QSL card checker

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