I would bet that the problem will be in the manufacture of the
individual cells, or impurities in the material used.
"Solar Grade" Silicon is of a lesser quality than that used for other
devices and sells for less.
I started working in the Silicon industry in 1961 when Polycrystalin
Silicon, or "poly" for short was grown in reactors consisting of quarts
bell jars.
Essentially HSiCl3 is decomposed into the metal Silicon (Si) that is
deposited onto a heated rod. Those rods at that time were 16" long and
maybe 1/2" to 3/4" in diameter along with a bunch of really nasty
byproducts which were recovered and processed into useful chemicals
Pressures were much less than 10" of H2O
These poly rods were refined and turned into single crystal material
through the "Float Zone" process that was time consuming, power hungry,
and costly. Look the process up in Wikipedia, or do a search.
There have been many changes in the manufacturing process producing poly
rods that require power lifts. I would guess those rods may be 10" in
diameter and far longer than the original. Yearly production from the
larger plants is measured in thousands of metric tons, while purity has
gone from a few parts per BILLION to tenths of parts per TRILLION.
"I think" the price of poly hit a peak of $400 to $600 per Kilo. "I
believe" it is now less than $100, BUT a number of solar cell
manufacturers are stuck in contracts at the higher prices while the cost
of solar panels could be less than the cost of installing them. This has
led to a number of companies being stuck with the cost of the silicon
being more than the price of the finished panel.
I've gone through a number of reasons a cell can generate noise before,
but the feast or famine cycle of the industry has led to the beginnings
a shake out where it's likely all but a few poly production facilities
will close their doors. One company started a new facility that was
expected to cost over a billion dollars. It was never started and I
believe, sold off as scrap. This is a highly competitive industry that
is extremely expensive to enter and very expensive to leave
I went through all that explanation to show why many companies are
cutting corners. Some of these austerity programs had side effects that
didn't show until a faulty panel(s) were installed close to a facility
that could hear those side effects. IOW a ham station. So they could
have installed hundreds, if not thousands of these systems before the
defect was discovered. This does not bode well for noise on the ham
bands and when a noisy system is discovered when a ham moves in next
door and the solar owner suddenly has to deal with replacing expensive
panels we are likely to be blamed regardless of what the law or FCC says.
73, Roger (K8RI)
On 8/22/2019 9:31 PM, Tony wrote:
All:
Quick update on my solar panel RFI case with SolarEdge. As some of you
may recall, I filed a complaint with the company in August of 2016, a
few days after the system was installed on a neighbors home.
The few attempts that SolarEdge made to fix the problem have all
failed. The most recent in 2018 involved applying chokes to the panel
optimizers which did little to suppress the noise.
However, while the crew was applying the chokes, we discovered that
the noise was STILL being generated with the system turned off. The
the noise only increased slightly with the system turned on.
It was later discovered that the solar panels at another installation
where generating RFI while they were disconnected from the system. The
discovery took place while the crew was working on a system owned by a
ham radio operator.
The faulty panels were manufactured in (you guessed it) China under
the Trina and Hanwha brand names. SolarEdge informed me that they are
working with that manufacture to find the problem and that they will
retrofit defective panels with quite units.
When asked when they might come out to check my neighbors solar
panels, they said "it wont be anytime soon".
So here we are, three years and counting.
Tony -K2MO
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Roger (K8RI)
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