The AM Forum

So my neighbor comes over today and after we bemoaned the loss of the last 2 Red Sox games to the evil empire, he asked me what I thought about our electrical utility offering to install “free” solar panels.  They apparently sent a sales rep through the neighborhood this week.  I told him I think in principle it was worth considering, but I personally had big concerns about RFI to the ham bands from those types of solar installations. At that point, my  wife heard us talking, and chimed in with the news that another neighbor, directly behind us, was taking up the offer from Eversource.  So it looks like I am going to have a
set of panels, presumably with on-panel inverters, less than 50 feet from my 80/40 inverted vee.  So I am asking if anyone on the forum has had any experience with having solar panels in such close proximity to their antennas.  If the RFI  indeed trashes the spectrum at my location, other than moving, is there any recourse to have the utility provide remediation?

Does the noise floor increase with panel output, and hopefully drop or go away at night?

  I did RFI complaints for the local utility here before I retired, the utility is only responsible for RFI off it's equipment. If the utility provides a solar system then that may be considered their equipment, the CT PUC might have info on that.

  I had one ham who had noise from 80 meters to 6 meters, the source was a utility interactive solar system on a school across the street, this was a 3 phase system and one of the inverters appeared to be the noise source.

   Another ham I know who had a utility interactive system on his home, the panels were tied together by an ether net and that was a RFI source.

    My HMO here in the Bay Area has been installing awnings over their parking lot for the past year that are covered with solar panels. A few weeks ago I went for an eye examination, I was listening to KFSO 560 KHz and soon as I got near the awning there was very severe RFI.

     The owner of Palomar Engineers, AK6R, has dealt RFI issues from solar installations in Southern California and has some good info on his website.

You'll be best off with a central inverter.  That's the least efficient.

Next is the micro inverter systems.  Those switch DC to sinewave 240 at the panel.  As long as good grounding practices are followed, these systems are pretty quiet.

Then comes the optimized panels, or panels with seperate optimizers.  These are the proverbial nightmares.  These are whole-system integrated.  They have each panel producing x amount of watts.  The optimizer keeps the voltage level the same, no matter if it's partially shaded or not.

This has the effect of keeping the voltage stable at the central inverter.  Higher input voltage means better efficiency.

However, they use pwm to control the voltage!  And, they don't filter it out....  Some brands being worse than others.

All is not lost, however.  Start taking sdr screen shots TODAY!  with noise level markers at your ambient.  Do it every hour, every day, for 2 weeks.

As SOON as the solar system comes online, you'll see it!  Start grabbing captures again.

Call the installation company.  Find out who actually owns the system.  It is their responsibility to ensure its compliant.  Force the issue.  I have seen solar systems ripped off a roof because the contractor was incompetent.  I have been hired by other companies to install the ferrite rings the manufacturers WILL provide to reduce or eliminate rfi.

Be careful, though.  Most of the rfi elimination kits do squat at hf. They are designed to restore the am broadcash band.  Money talks.  Here, again, is where your sdr screens hots come into play.


Yes, as the sun goes down, the rfi will reduce itself.  UNLESS!!!  Unless they are using any of the battery systems for on demand  or for net energy metering.  Then, they can go all night as well.

I'm pretty lucky.  As the solar systems wind down around me, the local pot farmers digital grow ballasts pop on.  So I get another 12 hours of rfi.

F all of this.  I'm moving.


--Shane
KD6VXI


(although no longer affiliated with any company, I've sold and installed almost all types of solar systems, charging systems, etc.  Both on and off grid. )

I wanted to add.  The typical rfi box that uses phasing will do wonders for a single solar system.  If you have more than one installed system, don't waste your money.

The best thing I've found to reduce solar rfi is an SDR.  Some of the noise banker algorithms are really good.  To the tune of 5 to 7 s unit reduction.

Doesn't help when the rfi is 50 over, but.....


--Shane
KD6VXI

There was a pretty good article in QST April 2016 page 33 that addresses noise issues with solar power systems. K1kP’s solutions were planned out in advance of the system installation. He had access to an operating system in the area so he was able to measure the sources, frequency and amplitude of the noise. He was able to get help from W1HIS a retired MIT professor who had extensive experience in RFI reduction techniques.

I thought it was very interesting but I don’t plan on getting a system anytime soon.

Steve
WA2TTP

In Spain the government solved the problem. If you put-up a solar system, they come, put a meter at YOUR panel and you have to pay tax over the electricity generated, TAX OVER THE SUN!!!!. That makes the electricity more expansive than buying electricity, which is the most expensive in whole Europe. So .... nobody has solar panels, problem solved ::)

Most Grid-Tied solar systems seem to generate little,   or perhaps even no RFI.

Some of the worst noise generator solar systems are called Hybrids  --  those that charge a low voltage battery with an MPPT battery charge controller,   and sell/buy power to/from the grid.   These systems generally use a 48 V battery bank,   and the solar charge controllers  (technically)  need NO EMI/RFI  emissions suppression,   as   FCC Class B  emissions testing for devices that are not directly connected to the AC power mains,   BEGINS AT 30.0 MHz  and continues into the GHz range.   These MPPT chargers are large switchers that usually handle about 4 kW of power  =  NOISE.

Microinverters,   and String inverters DO connect to the AC power lines,   and  need to pass Line Conducted emissions tests, which begin at 100 KHz (IIRC),   and extend to at least 30 MHz.   This generally means that inverters from name brand companies  usually are RF quiet.

A contester friend,    had a large solar system installed (Uniphase microinverters),   and noticed NO added RFI  on any frequency of interest.

The power systems hear are off-grid,   and use MPPT (Maximum Power Point Tracking)  solar chargers,   which DO generate some RFI,  which is fairly easily suppressed with  Ferrites,   running all above cables in EMT conduit (metal),   and running AC power feeds to buildings under ground,   and in Rigid or EMT,   above ground.

The only reason we moved to this low-density rural area,   was to leave behind PG&E utility power line NOISE,   and later,   much of that line noise  is masked by all of the el-cheapo,  lowest-cost producer switcher  gizmo  NOISE.

3 cents worth,   GL,   Vic

Got a check today for $112 for the extra power my panels pushed into the grid this year. Yes, my electric bill, excluding connection charges and special assessments, was -$112 for the year. I put this system up a hundred years ago, back before micro inverters. I actually picked the inverters by visiting various installations. The ones I picked were quiet as a mouse. I can't hear a difference when I turn them on and off. They are Xantrex inverters OEM'd by SunPower back then.

PS I don't want to imply this system made economic sense. Now it might. Back then panels cost what, two or three times as much as they cost now. The payback period now might be three years. For my system when I bought it I think it was roughly ten thousand years.

My neighbor is putting in a solar array using AP systems YC 600 micro inverter..It will be hooked to the grid so he can sell any power that is excess to his needs... His system is approx 800 ft away  from my shack...https://usa.apsystems.com/portfolio-item/apsystems-yc600/
Their literature doesn't mention anything about RFI suppression. I talked to the installer and he didn't seem to know about RFI.The solar company is working on the install today so I guess I will know soon enough.  I have taken some screen shots and will take some more.  I will report the results as soon as I know ....

Hi Steve,

It has been several decades since I have done any Emission Compliance testing. And there are some international standards that may well have equal or better emission limits for the HF spectrum.

The Data Sheet for the YC600 has this Compliance statement:

"Emissions & Immunity (EMC) Compliance FCC PART 15, ANSI C63.4, ICES-003".

FCC Part 15,   as a general statement is not a particularly high standard.

One model of these inverters  does use PLC (Power Line Communication,   assumed),   although this is the method used by Enphase,   for some time,   and those microinverters are known to be RF quiet,  in most installations at or near HF-active hams.

There is a contact phone number (Seattle,  WA),  noted at the bottom of the data sheet,   and other materials on their site:

600 Ericksen Ave NE, Suite 200, Seattle, WA 98110 | 844.666.7035 | APsystems.com

Why not call them,   and try to penetrate into,   at least the Applications specialist,   or  Applications Sales folks.

Try to find the FCC product ID number for this product.   And/or ask specifically about Emission Compliance,  perhaps stating that you are considering these inverters for your Hammie QTH,   or similar.

GL,   FWIW,   Vic

OM, please consider writing a guide for hams that covers the trade-offs between various methods and equipment. Here are a few questions that I'd appreciate info on.

• My sister just had a system installed by a company that sells them at Home Despot stores, and although there are no batteries, she does get enough of a discount on her electric bill that she considers it a good deal.
• I know other solar system owners who did it themselves, and they deride the panels-only type of setup that my sister got as a blatant ripoff that gives a perpetual lease of her roof to big energy. Is there accurate info about the trade offs and benefits of a panels-only system vs. a battery-based system vs. commercial-only power?
• I bought a house which used to have solar power, but no longer does. Is it cost-effective for a retired couple to put in a new solar system right now? What are the payback intervals these days?
• Are the utilities still obligated to buy power from solar owners?
• Will have an array on my roof raise my insurance costs?

Thanks for your time.

Bill, W4EWH

Thanks Vic...I'll take your advice and give them a call.   Steve

Bill,

First one.  Yes, as long as the system is sized correctly, it doesn't matter if you have batteries or not.  If you size a system large enough, you end up offsetting the power used during a 24 hour period.  All a battery system (like the Power Wall, Sohnnen, etc) do is allow you to fudge the power company if you're on time of use.  In a TOS system, your kwh billing varies throughout the day.  A battery being charged up during soap opera hours, then used to run your home during peak purchase times makes sense, in this case.  You charge the battery all day, not using the power from the utility.  Then, during peak power purchase times, pull from the battery to power your home.

This is TOTALLY different from a non grid tied battery system.  A non grid tied system charges the batteries all day, and you pull all the time.  Not just during peak energy times.  These are also called off grid.  In other words, no utility.

Second:  the only thing that would give a perpetual lease to big energy is if she signed a lease. And, depending on her age, this might be the right thing to do.  My 'money guy' looked at a cash purchase of a large solar system..  Writing a 50k dollar check wouldn't have been anything.

However, he found that with the projected 15 years of his life left, he wouldn't see a return on the investment.  Instead, he leased a system that makes sure he doesn't have a power bill for the rest of his life.  He is guaranteed a set rate for the next 20 years, and his wife keeps the house at 75 degrees.  It's 115 here in the summer.  He's happy.

If you have 20 plus years, (and this is TOTALLY dependant on the cost of the system, the interest charged, how much power you use, whether your utility wholesale purr hades power from rooftops, etc), then purchasing a system can make more sense.  Typical systems pay off in 5 to 10 years.  I've had smaller ones pay off in 3.  After 3 years, the single 65 year old man will live the rest of his projected life, electric bill free.  He had a 40 dollar a month bill, though.

The payback interval is totally dependant on the cost of the system.  My last employer could get people off CARE or FERA.  Yes, people on welfare, he could get them into solar.  However, it wasn't a gargantuan solaredge system with remote panel by panel monitoring!  It was a central inverter and ching fong panels.  But, these people now have a 0 dollar energy bill, and pay 75 bucks a month for 10 years.  Which beats the cooling bill in summer when it's 115 out!  So, if you go with a basic system, have a company that will look aggressively for the best deal for you, you can easily come out ahead in 5 to 10 years.  Possibly a lot shorter if your in a cash purchase position.

The rules governing utilities are a state by state case.  If look in your area for real answers to the other questions you've posed.  Here jn California, they are reality trying not to, but the CPUC only let's them get away with so many shenanigans a year.

I know people that got in 10 years ago that get 1 to 5 hundred dollar a month checks.  They have solar FARMS in their back 40 though.




Didn't mean to derail the thread....

--Shane
KD6VXI

The gripe I have w/ the solar panel thing.. if they are 'my' panels.
The power company charges you retail but pays you wholesale for what you put in. Not going to play that, let's them have it both ways.

In some places it's like that. In many places it's not. As Shane says, it's a state by state thing. In fact, it's even a county by county thing. It has been retail in and retail out in most locations. That is they pay you retail rates, not wholesale, for the power you push into the grid. Utilities think this is a raw deal for them and are lobbying to change it to retail in wholesale out. Some have succeeded. Many have not.

Google "Net Metering" and stand back.

Well, the neighbor’s install started this past Friday and will come on line this week.  Will consist of 20 panels and a Solar Edge HDWave central inverter located at the main breaker panel.  The installers are doing what appears to be a good job on the wiring, everything they have put in is run in steel conduit from the wiring coming down from the roof and what is going to the main distribution panel and incoming commercial meter.  I have driven by a number of similar looking installations in town which I assume are similar ones put in by Eversource, and have not heard any significant interference on the BCB in the truck radio or on 40 meters on the little K1 QRP mobile setup. Keeping my fingers crossed!  Since Eversource serves the majority of towns in CT, I’m thinking the ARRL people who have been following the solar EMI concern may have some feedback from others in the state on these systems.  One thing that caught my attention when my neighbor was showing me the install progress was that the panels that were staged to go on the roof did not appear to be new, the frames and the barcode stickers showed considerable weathering.  Looked like they had been installed previously elesewhere.

I have clients with this attitude. I tell them solar was never designed for a payback.  Your payback is sizing it correctly so you don't have a power bill, and your solar finance bill is smaller than the power bill.

Take it a step further and install a battery to power yourself at night.  Completely (not really, you still have to maintain the interconnect) autonomous power!

On the net metering, they are also introducing TOU here. Time Of Use.  Power will be cheapest for residential customers from 9a to 5p.then it rises, exponentially until. The end of prime time.  After that, power rates go back down.

Yes, they got the public utilities commission to guarantee revenues.  So, we install batteries so you never run off the meter.

--Shane
KD6VXI

If you have a home garden and have extra tomatoes, you would not expect to go to your local grocer and have him pay you retail for them. Same concept.

It is a not fair to other customers of the utility to pay the solar customer retail for the feedback. Remember the solar customer is essentially a power generator. They are only displacing some of the costs associated with generating the electricity.

However, the retail cost includes expenses that are entirely unrelated to generation. A person who installs solar in effect becomes a generator. However, they expect the utility to provide backup service when their solar cannot produce 100% of their power needs (very expensive BTW), maintain the lines, infrastructure, support etc.

Most people, understandably want the utility available when their installation is not able to meet their needs. Utilities in deregulated states are often still required to act as the "Provider of Last Resort". Essentially, the utility must act as a “back up” electric service in the areas that they cover So they have to build and plan for sufficient resources to be available when you want it. There are costs associated with that.

Carl is right on the money.

Also, in California you are required to have electric hooked up, if it is feasible to do so.  One side of the political spectrum says its intrusion on our rights.  The other says it's for emergency backup, etc.  Cases to be made for both sides.

--Shane
KD6VXI

Can the home owner depreciate the panels ?

KLC

That is a pretty complex question and I would talk to your accountant and lawyer. There are a lot of elements to that question. A you buying the system, leasing it or using some of the more obscure plans where the company retains ownership, and you allow use of the roof.

If you are going to own it outright as a homeowner there is a substantial FIT credit that was extended in the recent tax bill. However, usually to claim depreciation you have to be a corporation. I suppose theoretically you could set up a singular corporation to "own" your system and pay yourself for the electricity. The corporation could then take depreciation on the equipment and related expenses. But now you are a commercial power generator and may be subject to all sorts of filings and regulations on the state and Federal level as well as corporate taxes.

Seems like way too much work for the benefit.

I have some questions regarding outright ownership costs, DIY approach:

I once looked into the costs and maintenance of various self-generated power solutions.  

My power bill runs about $1500 per year which is not too bad.  The first thing I looked at was putting up a wind turbine on one of the towers.  We're on top of a windy 800' hill and have access to several tall, very strapping towers for the turbine. (190')     After looking at the cost of the blade and turbine, interface - and the cost of replacing the bank of batteries periodically.... PLUS what would be the cost if the turbine crapped out or the blade fractured, etc.?  How about bringing in a crane every time  - and labor etc?  I found it was a big loser and then better appreciated the cheap cost of electricity from the corporate giant.

The solar solution seems somewhat better, though we must remember the cost of replacing large battery banks (if used) and how long do the solar panels last? Are they prone to wind storms, tree branch missiles, snow and ice and other weather damage?   A large farm of solar panels seems like an easy target to hit at random.

In the distant past, I figgered by now there would be a way for everyone to have a small nuclear power source. One that was foolproof and could not be used as a weapon. But that obviouly never happened.

I'm under the impression, just like buying a new Tesla electric car, in the end self-generation is a financial loser or break-even venture (at best) at this point in technolgical advancement. Thinking that the little consumer can compete with the economies of the large corporate power companies and the oil companies is currently not here yet. They have it down when it comes to economy of scale.

I'd like to hear comments about the cost and replacement of a large 12 volt battery bank, maintainence and the crap-out factor that comes with any of these systems...

The fact that solar panels are becoming more common for individuals and wind turbines are very rare tells us a lot.

Also, obsolesence - have solar panels advanced so that a large panel system 20 years ago should  now be replaced by a more modern, smaller, more efficient and cheaper panels? IE, more future expenses to upgrade?  Has solar technology advanced at a fast pace like radio or computer technology - or has it been more like a slow turtle pace like the battery or electic bulb over the last century?

And I wanna know - why aren't there hundreds of hydro power plants just off the coast of our country taking advantage of the tides, just like the Hoover dam?  I would think channeling the tremendous force of water as it flowed every 6 hours could be accomplished in a big way.  Ocean oil drilling rigs and all the associated mess of oil power seems like a harder solution to energy.  

T

You need to talk to Vic, K6IC. He's off grid, owns a bunch of batteries, has a lot of solar panels. I do know this: solar panels have become dramatically cheaper in the last few years but not dramatically more efficient, not silicon ones anyway. I believe the theoretical maximum is 29%. In the labs they are hitting 26% and on the roofs 23%, up from 20% ten years ago.  They often talk about a 20 year life span but they seem to last a lot longer than that.  The degradation rate is something like .4%/year so after 20 years they are still producing .... dang. Can't find my slide rule.

I'm pretty sure the answer to the tides question is it's hard, much harder than it might seem.

Here near Albany, NY my neighbors two very large solar panels are less that 30 feet from my receiving antenna offer no RFI from 22 MHz to 1.3 GHz, Her system is a direct connection to the grid where no storage is used in her home. There is a large DC dis-connection switch right next to the meter and I think it said that it was rated for 480 volts DC? The only problem I have with her system is that several times during the winter months, the solar panels cause a snow or ice avalanche! The accumulation of ice or snow is more that 500 pounds per panel and they come thundering down as soon as the sun raises the temperature on the panels below the build up of ice or snow, endangering our cars or people that may be walking or driving under them. When the snow hits the driveway it compacts making it very difficult to snow blow the compacted snow. The first winter after she installed the panels it was all ice that came thundering down so I warned the xyl where to walk and not park her car in the area. I think there must be someway to heat them or put up a barrier so we don't have to worry about future avalanches?  Does anyone have any ideas on how to avoid build up of snow or ice on panels?    

Hola Terry,

Interesting to hear about the snow and ice issues.

One solution would be to build a massive frame, something like what the UHF guys do to mount their huge eme arrays.  Make it tilt and rotate. (alt / az )  Then when the forecast says snow or ice, put the panels into an alt direction facing the ground. As a bonus, during sunny days both the alt and az could rotate to follow the sun for maximum received solar energy.


It wouldn't be easy with a massive panel array, but for smaller stuff like I see around here, it is doable. I'll bet there are already manufacturers specializing in this stuff now.


K6JEK - thanks for the comments.

T

They make tape heaters.  Copper foil with a small current through them.

Same principal as what they use on the small pizza box size dss dishes, although they don't cover the entire panel.  Just a small thin strip along the lowest point, to keep anything from. Building up on the lip.

RainX works to prevent buildup as well, although I've never tested it to see if it also lowers the sunlight.

This is a real problem.  There are fixes.





The disconnects should all be rated at 480 or 600 vdc.  On the DC side.  On AC side, they are rated for split phase 240 although most buy in bulk and companies that do commercial will usually buy ones rated at 480 for everything.  Less inventory.

--Shane
KD6VXI

So while my son was a firefighter here in NJ I recall him telling me that if there's a house fire, and solar panels on the roof, "we aren't going up on the roof". The local Target had a fire. Solar panels on the roof, so the local power company had to come down and disarm them before the FD would go up on the roof.

We are now required to install what is called RSD or Rapid ShutDown.  It kills all output to 1 volt per panel.

I can't blame him, 4 to 500 volts DC is nothing to sneeze at.


--Shane
KD6VXI

Shane, what does this amount to for existing string inverters? I'd guess a remote disconnect up near the panels that somehow works in tandem with the existing DC disconnect near the inverters. Did I guess right?

Existing systems will not be required to retrofit.  Stupid.

If it's an optimized string system usually a simple firmware update gives each optimizer the capability to RSD at 1 volt. 

If it's a simple string system, their are a couple RSD boxes available.  Some integrate with an inverter that has a 120 v relay in it.  The RSD box will drop the string voltage to a regulated 24 volts and you run a 2 conductor cable to either the inverter or a pushbutton shutdown (panic button style).  That button just interrupts the 24 volt signal looped.

In a dumb string system with an inverter capable of interfacing with an RSD all they have is a relay that shorts upon successful self test on the inverter.

In any case, the RSD is supposed to be wired to where if the main disconnect to the house has been shutdown (main breaker), you can ONLY have 48 volts ANYWHERE on the roof.

If you Google Fronius RSD, those have pretty good instructions.  Their RSD box is also a combiner so you can combine several strings rooftop before running lots of wire back to the inverter.  A single twin run of 8 is usually cheaper than 4 runs of 12.  I use the combines to also split a roof.  You can combine strings on the east and west side of a house.  As the sun moves, one string comes down in current, the other increases.  They have steering diodes to keep you from backfeeding, and the mppt controllers in the inverter keep the AC power constant.

Win win for Johnnie and Jamie homeowner!

--Shane
KD6VXI

if a solar panel for example is about 20% efficient in converting light into DC, what is the other 80%?  Is a component of the 80% heat generated in the light to DC conversion? and if so, anyone know what percentage?  I'm guessing the remaining % is heat created by IR absorption on a dark surface after the conversion process. I'm curious to know how much heat is generated in conversion process.  Can't seem to find that.

Indeed heat and reflection of the light not absorbed. Energy cant't be lost.

UPDATE...My neighbors 10 panel solar array is up and running....I haven't noticed any major buzzies or other interference from the installation with the exception of some sigs that show up as  diagonal lines moving thru the spectrum.  Since the neighbors system has no batteries and only produces power when the sun is shining, I should be able to check after dark and see if these undesired signals are coming from his system..or I could have him "turn it off" and see if the sigs disappear?

About thirty five years ago, a friend installed a hot water solar array on his  roof. It was a commercial setup and while I read the blurb on it I never asked how well it did? So the question remains since there is obliviously more energy hitting the panel than can be extracted, are there combination panels out there that make power as well as heat your hot water or swimming pool? I guess I could Google it, but I think I may receive a better answer here from those who have a hands on experience?

In principle that is possible, but there are a few "buts"
When the water heats up, the panel is hotter. That means that the electrical cells loose efficiency.  You want to keep them as cool as possible
In addition, the solar cells do not have a low IR radiation coefficient as a solar panel for hot water has, so the heating of water is much less efficient as well. Hot water panels have a layer that is black for visible light (and there is where the energy enters) and are low radiant for IR, so they do not loose heat by radiation.

That seems it would lend itself to a partnership where the back of the solar cells were to be coupled to a water flow to carry off the heat and use it to heat water. Might not be as efficient as a direct impingement solar water heater, but might be worth exploring. Water cooled solar panel. Might even allow for a reflector arrangement to direct more sunlight on the cells to get more out of them while still keeping them in their operating range.

The latest and greatest for solar is two sided panels for shade structures.  They harvest photons from above and reflected energy from below.  I do not recall how much more efficiency you gain per square foot though.


That, and stick in or roll on panels.

I honestly believe we have seen peak efficiency.  So does Elon Musk.  He said years ago that extracting another 2 to 5 percent effeciency out of the panels would cost billions.

The market was better served opening up another factory to drive existing costs down.  He saw more efficiency in producing panels rather than conversion efficiency.

Probably right.

--Shane
KD6VXI

My across the street neighbor’s 20 panel grid tied system has been operating for about 3 weeks now.  Have not yet noted any increase in noise floor anywhere in the RF spectrum.  Another system is to be installed on the house that is just behind our backyard and much closer to my HF antennas.  Keeping my fingers crossed.

Looks like these 2 solar installations are pretty quiet..   That is a good thing

regarding efficiency of solar panels: for a while now there’s been research going on in the area of optical rectennas...literally, antennas to receive the Sun’s visible spectrum and to directly rectify it to DC with appropriate diodes. The promise of such a rectenna is ~70% efficiency. The stumbling block thus far has been the development of appropriate diodes. The entity that builds such a thing, be it governmental or commercial, will change the world.

Peter

quote
That seems it would lend itself to a partnership where the back of the solar cells were to be coupled to a water flow to carry off the heat and use it to heat water.
unquote

The problem is that you need to pump up the temperature to get hot water because you don't want to heat-up the cooling water.
GaAs solar panels can be used in concentrated system using fresnell lenses or mirrors. They run up to 35% efficiency, but need to be cooled and are very expensive

Chris - thanks for posting this.  I have seen lots of solar come online here.  Unfortunately, the noise level here has increased dramatically during the past 5 years and the noise comes from all kinds of stuff ( grow lights seem the worst).

Hopefully we can check solar off the list!

My next RFI battle is going to be LED street lights that the town is charging forward with buying. No idea what noise they might make.

73
Tom

[quote author=Tom W2ILA link=topic=43903.msg317908#msg317908 date
My next RFI battle is going to be LED street lights that the town is charging forward with buying. No idea what noise they might make.
73
Tom
[/quote]
We, like many people have gone pretty much all LED lighting at home and I have not noted any RFI issues on HF, except for a bank of can lights in the kitcen overhead that are controlled by a dimmer.  The dimmer has always been an issue even with incandescent bulbs.  The only RFI I have observed  at home from a non-dimmer  controlled LED bulb is on an AC powered FM clock radio I have on the workbench in the garage that shares an outlet with a swivel type work light.  The radio has a 1/ 4 wave wire antenna that is only a couple of feet from the light.  I get a broadband hash that is audible, but does not totally interfere with stations of already marginal signal strength.  The LED lights in the shack share circuits with the receivers and no problems on HF, no VHF radios in the shack.
 
OTOH, while operating on HF mobile, I have frequently encountered hellacious interference from LED traffic lights, sometimes at a range of several hundred yards.  Usually the offenders will have some of the individual small LEDs that make up the field of the red or green meatballs not lit, or they are rapidly flickering on and off instead of being fully on.

This weekend I just got rid of all my 4ft florescent lights and replaced them with the 4ft LED that Costco offers. Absolutely, no noise I've found. These are the totally new fixtures, not the LED tubes that can be installed into existing ballast equipped fixtures. I just wanted to get rid of the ballast as well. Like ~ $24 ea 0- great buy. Also no cold flicker out in the garage in the winter.

I have put 32 LED lights in my new house from the brand General Lighting. Could not get other lights here in Costa Rica. When I switch a light on, no SW reception, no MW reception, a few TV channels disappear, interference at FM. Just plain noise. They do not comply to anything.  There are simply NO filters at all in those lights
So I have to modify all lights, put filter capacitors in the converter, shorten the wires from the converter to the LED's and put shielding over the converter connected to the LED housing.
Those .@$#* chinese dump there shit all over the world and use the fact that there is no sufficient control here here Costa Rica.

Before you go through all that rigamarole, I'd stop.

You need common mode filters on the power supply wires.

How do I know?  I've got one in my possession now!  From the EMC compliance kit from a crappy chicom light that didn't meet compliance.  It would completely kill everything rf.

Interestingly enough, I'm playing with two of them and my new VNWA.  So, I'll snap a pic of them on the phone and upload.  This way, you don't waste your time and money and shipping, etc.

I'm not sure what the material is, but if someone can tell me what to test for, I'd be happy to.  After installation, we where able to get FM and AM radio reception.

I did a sweep of the emi filter, and I've enclosed the display.  Hopefully it will help identify what you need?  The single wire with multiple turns is one I took apart and was attempting to use for something else.  It does show the core and color. 

Incidentally, biggest time waster of the millennium, the VNWA.  I can find all kinds of excuses to sit in front of the PC and run tests on components.  Have swept Murata filters, crystal filters, etc.  Real eye opener.

--Shane
KD6VXI

The cores I have in this jug may or may not be these:

https://www.westfloridacomponents.com/IN114PF05/Ferrite+Core+Cylindrical+Broadband+Steward+28B1225-00H.html

Ive no interest in the company.  The cores look to be the same in construction, are marketed for EMI / RFI and they give resistive values across the spectrum.

3 or 4 (if you can fit them)
turns of wire on the leads between the drivers and the led should be the magic ticket.

--Shane
KD6VXI

Thanks for the replies
I tried several ferrite cores without noticable effect. The RF impedance seems too high to have effect, the "interference" antenna is too short I think
I am afraid that the problem of the general lighting LEDs is slightly different. The AC comes in into a converter that gives a DC current . Than a 10 inch wire with a connector connects the DC to the LED device, a metallic ring with LEDs at the inside and the same type of plastic light dispensers(??) like in the backlighting system of a PC screen. Fortunately the ring has a metallic plate that closes it at the back side.
The plate is painted and does not make contact with the ring. The DC converter does not have any filtering, so the LED device with the 10 inch cable acts like an antenna where the converter is the RF generator.
I shorted the wire to 1 inch, mounted the converter at the backplate, mounted a shield over the converter all well connected (removed the paint where the screws are)
So no more antenna. I only have to prevent that there is an RF voltage between the AC input and the shield, so two 10 nF caps from the AC to the shield.
That solves it completely
A little work, but no money involved and with good results

The EMI compliance filters go on the DC side.  From the LED itself to the driver (power supply).  They go as close to the 12 volt power supply as possible.  The switchmode supply is what causes the rfi.  The trick is to find a mix that filters from DC to daylight.  Or at least filter the bands you are interested in / use.

The OTHER thing you can do, and is really the kitties meow, is this:

Use a 12 volt float charger (if the LED are 12 volt, some are 24, etc).  Float charge a battery.

Now you'll be the envy of your neighbors when the power goes out and you're still lit up.

You completely bypass the internal 12 volt switch mode supply.

Sounds like you have it figured out, though.  Good luck, I deal with this on at least a weekly basis now.  Everyone in the USA says radio is dead, etc.  Sure.  Install some unfiltered LEDs and see how many office people still listen to the radio.  It's a real eye opener.


--Shane
KD6VXI

This has all suddenly become very relevant to my situation. The bride and I are looking for new digs, and the place she's fallen in love with is covered with 24kw of grid tied solar cells. I'm rather fond of the house too, but not so down with the end of my ham radio career except for mobile operation.  :o  So I need to figure out whether this is going to be a disaster on the receive side, or something tolerable, or maybe not much of an issue at all.

Perusing back through this thread, I see some signs of hope (it's grid tied system, which seem to be quieter) and some signs of worry (it uses enphase microinverters). We're going back for a second look, and my plan is to take along an RSP2 and a buddipole system and do some sniffing on various bands from the back yard to see how bad it might be. That was an interesting discussion with the real estate agent.  :D   It's also got geothermal heating/cooling which has potential with variable speed motors to cause noise as well, if not as continuously. I'll have to have them exercise that system too. Neighbors are all 500' away or more, so hopefully we'll be spared the plasma TV and other part 15 miasma of suburbia.

Looking at the terms of the lease, they aren't all that friendly either. NO chance of modifying the system to quiet it, or even turn off when I want some quiet. And with the microinverters on the panels, I guess I won't be able to turn them on and off anyway since they power up when the sun rises and quiet down, one hopes, at sunset. And they want the next sucker er customer to assume the lease and all it's obligations for the next 16 years, plus buy out the system at the end. That may be a show stopper for the wife, even if the system is sufficiently RF quiet for me.

I like the idea of solar, I have several hundred watts of panels and quiet charge controllers for portable and emergency use and want whatever house we live in to at least have some solar based backup power. But I don't like being tied to a company I didn't choose, who installed a system that may not be quiet, for the next decade and a half. What happens if one of their inverters goes wonky noisy, will they service it? Do I as a follow on lessee have any leverage for getting the system made quiet? Is there a way to exit these leases - they say only two things can happen, new sucker signs on (after being approved to) to the lease and has all the costs and obligations OR the current lessee has to pay it off, but it still stays on the roof for the term of the lease - possibly generating unacceptable noise. Neither option is very attractive and could prove a serious impediment to striking a deal on the house. 

For me, if I could wave my magic wand, I'd like the current owner to pay off the lease, which will probably get folded into the purchase price, and then get the company to abandon the system in place for a realistic cost of the panels. I'd then arrange for it to be rewired so it ran quiet and also fed some decent sized backup batteries. I don't know how likely that is - probably pretty unlikely - but if the company makes the bulk of their profit from harvesting the subsidy at the installation, plus the lease costs, what else is there for them? They want you to buy the 20 year old system at an inflated new price at the end of the lease, but there is the option of having them come remove it for $1k fee. Who knows what shape they would leave the roof in. Or if they would even exist as an entity in 15 years. They aren't getting paid for the power being delivered, so once the lease is paid off, all they have to look forward to is the buyout or removal payment at the end? Or am I missing something here? If that's the case, getting paid more than the salvage costs of 20 year old removed panels would seem to be a reasonable deal for them, plus they don't have to sweat power delivery for the remainder of the lease and any system repairs that might entail. Anyone know if they are open to that kind of negotiation?

Plan B might be see how far away from the house and system I would need to put the receive antenna farm to be clear of the noise. The house site is in the middle of a nice chunk of woods, it wouldn't be too hard to move the antennas 100' or more away - just the expense of good low loss feedline. Any thoughts on how far away one needs to be to be clear of the generated crud?

Plan C is walk away and keep looking. That would make the lady sad, but you have to be prepared to do that.

Panels are Kyocera 'snap together' panels. The microinverters are enphase. And the lease company is Astrum Solar LLC. If any of those details help. 

The plan is to go check it out in detail this weekend. Any suggestions gratefully accepted.

The solar sys sounds a lot like a "time share" .... sounds OK at the begining but the more one looks at it.....

KLC

That's my take on it, even without the RF noise concerns. But I'm seeing a lot of houses with them on them around here. We're very 'green' ya know.

Seriously, we'd probably have made an offer on the house but for this issue. We may end up walking away because of it.  :(

well, ya can always bite the bullet and install your own system.


5,300-Watt Expandable Poly-Crystalline PV Grid-Tied Solar Power Kit

The Grape Solar 5,300-Watt Polycrystalline Grid-Tied Solar Power Kit can generate between 3,800 kWh and 8,900 kWh of electricity per year. Unlike other power generators, there are no mechanical moving components; therefore, maintenance is virtually non-existent. The kit consists of high efficiency Grape Solar 265-Watt Polycrystalline panels and Enphase IQ6 micro inverters (including accessories).

$10184. 99 at the friendly homely despot.........


klc

batteries not included.


klc

Sorry I didn't get to your pm earlier....  But I figure I'll address it here for those whom may be in n a similar situation in the future.

Enphase.  I love them.  Great product.  As to rfi, I was able to sit in my mobile unit and work 40 to 10 meters at lunch.

This was installed correctly, in a sunny day.  This in no way means your system will be installed correctly, however.


Big problems to look for:

Grounding / bonding.  The pipe needs to have the ground wire, via a 'bonding bushing' connected at BOTH ENDS!  Even the 'loose end' on the roof.  If not, you've created a huge choke that will have a quarter wave of impedance at whatever the length of the pipe.....  Give or take.  This is in the case of an insulated ground wire, pulled through the conduit.  If they use an uninsulated, then by code you cannot pull that wire in conduit with any other wires.  And if they did, it can create millions of areas to arc or short to the pipe, causing scratchiness in your receiver.

Loop ferrite in and out of the micro inverters.  The Enphase system uses a 'string system' at 240 volts.  Each panel is optimized and converted to line level voltage at the panel.  This, and optimizers, are the most efficient systems.  The ferrite used will determine the freq you want to use.  I wouldn't use type 43, if all you are interested in is 600 meters.  Jim Brown's rfi tutorial will be emminsely valuable in choosing the correct ferrite, but think type 43 and 61.  Use as many turns through the core as possible.

Make sure EVERY rail in the roof is bonded.  Make sure every panel is using 'bonding clamps', which have 3 to 5 teeth that bite into each panel when torqued down.  They can be reused once, so keep that in mind if panels have to be removed. After the first reuse, the nubs start to wear down and don't bite into the aluminum frames all that well.

There are so many variables that it's impossible to cover every scenario.  But, Enphase is a good system.

As to how they make their money?  Lots of different ways.  I know of one solar company that sells the lease to you, then turns around and sells the owned by them system to investors.  In that case, it's almost impossible to buy the system.

As to purchasing it in 20 years, that's a fools dream.  The power production of the panels will be down far enough coupled with continually rising energy rates that the current system won't be able to cover a third to half your bill in fifteen years, much less 20.

Typically your 'lease timeframe' matches whatever production guarantee time they get from the solar panel mfg.

And none of them have been in business for 20 years, none of the panel te h has been around 20 years, so it's all a guess at this point.







My advice?  Get an air band receiver and on a VERY sunny day, drive towards the house.  Turn the air band in about a mile away.  If you notice the ambient noise getting louder (or increasing the s meter),I'd say you are going to have some work to do.

In rfi work, yiu almost ALWAYS want to start at the highest discernable frequency.  Allows zeroing in n a lot easier!


--Shane
KD6VXI

Hi Shane, thanks for the detailed reply, and for sharing it with others who may come across the need in the future.

I don't know how much access I'll have to the roof and wiring details, I'll bring a pair of binoculars. It's possible the owner, who is a tech guy, might have paid attention to how things were installed. Ferrites if they are there I can probably see with the binoculars, but not tell the type obviously. I'm primarily interested in 160-17 meters. If I end up climbing the roof in the future to surreptitiously add ferrites I'll keep that in mind.

I set the TM700 on airband and picked a quiet frequency and did a drive by yesterday. The house is remote from the road, but you said from a mile out one might hear things. At 1000' I didn't notice any change in the background noise on 122.95. I had the HF rig on 40 meters, and at one point going near a power line I heard what sounded like some buzzing or frying noise, but I don't know if that was injected by the solar system into the line, or coming from one of the other houses or what. My old neighbor had a kiln with a temp control that must have been a grown up version of a fish tank heater with it's buzzing and arcing. That would inject noise into the lines that I could hear for blocks, and it peaked up at her house. Fortunately she mostly did that in the day time while I was at work, but some weekends were pretty noisy for radio.

I may bring along an HT that is multi mode, or an FT817. That on AM plus a satellite yagi might let me zero in on noisy bits.

Saturday's weather isn't looking to be too sunny, but I presume they will be active and making some power even in overcast conditions, right? We have limited ability to schedule a visit and no ability to schedule the weather, so we have to take what we can get.

As far as how they make their money - I know a lot of it is in harvesting the subsidy at install. And obviously a lot is in the lease payments over time. As you say, probably none of them have done any buyouts at the end because it's a new industry. I'm thinking that between the subsidy and the lease payments, that's the bulk of the money they are making. So maybe they would be open to some sort of early termination arrangement if they got their money, and enough to make it worth while. Else if we go forward, they can look forward me bugging them to make the system quiet. I don't know how much of a stick the FCC can be used as in that process. Based on how they treat other part 15 problems, probably not much.

Yesterday was a sunny day, and as I said, I didn't see too much issue on HF, maybe some buzzy near the power line, 1000 feet away. I suppose I could set up a receiving array a fair distance from the house, maybe with a loop antenna to null out noise, if the worst case situation came up. (Hmmm, build an upconverter from 0-30 mhz, to 420-450 mhz, beam it to the house, and downconvert and feed into the RX only input on the Anan200. Hmmmm.) 

I do wonder how far away I would have to put a receive antenna. If it's only a couple of hundred feet, that might be doable on a coax run. I do have a Pixel loop at the current qth about 100' of RG6 away from the house for a low noise antenna for dealing with the neighbors kiln and other noises. Plus this property would have some room for beverages in several directions...

Hopefully some of this will become clearer on Saturday. Or maybe there will be another show stopper and it will be a moot point.

Thanks again for the helpful info.


 

Update - went to the house Saturday to do some RFI studies and a more detailed walk through. Still love the house, and enjoyed the land tour,  but...

The day was overcast and rainy. Despite that, as we pulled up, we could hear a noticeable increase in noise on an Airband clear frequency on the D700. It sounded like a 60hz rasp coming up out of the rush of background noise.

RSP1 running SDRuno or SDR-radio showed a not too bad noise floor on a 48 inch vertical whip on the car, but every once in a while there was a burst of noise peaks like a picket fence across the whole band on various bands. I think it was the microinverter(s) trying to start in the dim light conditions - firing up and then quenching when they couldn't sustain the load. The peaks were a Khz or two apart and as I recall not that narrow a spike. Looked like it would pretty effectively remove any radio reception. When they weren't present, I could hear various nets on 75 meters without much trouble. I couldn't tell much about the bonding of the panels, and couldn't see where the microinverters or wiring were to look for toroids or anything. But the conduit coming off the panels down into the house was all plastic.  >:(  No bonding or RFI suppression there. Kind of made me think it was a cheap and dirty install with no concern for RFI. 

Seller wasn't too forthcoming on the system. Basically the whole shebang saves him about $40/YR on electricity.   :o   Wow, to encumber the house with all that and the lease for that little amount of money? They did it to 'do their part' being green. When I inquired about the noise issue his answer was "well I can't do anything about that".   :(

Going to try to reach out to the lease company and installers to see what I can learn about options there. But this may have just blown his sale to us. Too bad because otherwise we'd be making an offer. Maybe we'll make one contingent on the solar being GONE and make it his problem.



 

Well, $40 worth 'O juice. For that amount of green, they should have kept the lights off.

"              Maybe we'll make one contingent on the solar being GONE and make it his problem.        "

It's worth a try.  Good Luck........... Ya know, you could move up here.... ..

klc

bad biz to pay for a lease receiving no tangible good while others make the money off your payments for doing nothing. parasitic setup looks like. I'd run the other way!

run Forrest....RUN!!

I dont think Kevin has no stinkin forest.


KLC

Here in NJ, most of these "deals" have the home owner sign away any rebates and energy credits to the leasing company. The saving to the home owner is a fraction of what you could save if you own the system.

Yeah, I'm trying to understand what the lease company gets and when. I know they get the 30% subsidy, which makes it worth their while to over price the system. Then they get lease payments for 20 years. And at the end they want to sell you the degraded system at the new inflated price, or you can pay them a kilobuck to come remove it. It is a pretty bad lease, the only benefit they really got out of it was 'greenie points' with their friends.

One of the lease transfer options is for the seller to prepay the lease to it's end - and no doubt pass the cost to the buyer. Then all the lease company has to look forward to is 16 years of managing and fixing the system for a $1k  payoff at the end. Seems that there might be room there to pay them to walk away so we could take over the hardware and make it RF quiet.

Don't know if we can make all that work or not. I'm going to explore it a bit more before we give up. The property has enough other advantages to be worth a little more digging on my part.

And Kevin, we have 8 acres of Forest at the current QTH. But the new one would have room and trees to hang Rhombics.  ;D

I've got a good friend (W2CET) who bought his system outright. I think the payback was ~ 7 years, but I've seen his monthly bills, which during the summer are often $20-$30. He's also accruing energy credits which he can hold on to or cash them out. He's the one who told me to stay away from the lease deals. If you install a system it's also advised you have a new roof, otherwise replacing the roof down the line will be a very expensive job.

Spent a fruitless lunch hour trying to talk to one of the solar companies about the lease. First the shell game of changing company names about 3 deep, then the shuffle off to you can only talk to the lease company about stuff, then their layers of name changing to finally fetch up against "We can't talk to you without the homeowner approving it"  Can't talk structure of the leases, can't talk part 15 details, can't talk about any of the general things I want to know, until the homeowner says it's ok. Riiiight. Based on their customer service attitude alone I don't want anything to do with these people.

Friday is supposed to be sunny so I'll try to get a better idea on the magnitude of the noise problem.

The Rhombic prospects are beginning to dim.   :(

Did a follow  up visit, but had less time and access so I just used a 48 inch whip on the mobile with the RSP2 and also tuned around with the TS480 and D700. The D700 got raspy on an airband channel as I got close to the house - 60hz rasp. The 48 inch whip showed some noise, but not as much as I feared on 40 and up and I was able to copy other stuff on the band on both the RSP and the 480. What spikes there were I couldn't be sure if they were from the car or the house.  I swapped to the screwdriver at on one point (tuned for 40) and saw some more noise, but still not too bad. But on 75 meters there was a big noise floor hump and a bunch of spikes about 1 khz apart. Time ran out and I drove away while watching that and it didn't really go away as I drove off - didn't drop like I expected with distance. A moment later the spikes all went away at once, and a mile away the noise hump was still there but maybe down a bit. That seems to be unlikely to be the solar system, more likely to be something in the car or associated electronics that I've not noticed before because I wasn't using a spectral display just the TS480.

At this point, I figure I can either manage with the daytime noise (this was tested at noon) or work to mitigate it and/or set up some receive antennas away from the house far enough to be away from the noise. I've got a pixel loop that I planned to setup 100' away in any case, and have hopes for some beverages or other receive antennas.

The lease is still ugly but we're trying to see what can be done about that. But from an RF perspective, I'm cautiously moving forward.

 

The whole thing with leases was to get solar in the roof of people who can't qualify for the loan or who couldn't pay for a system outright.

We where able to get people financed whom had fallen on hard times and where receiving welfare.....  That 40 bucks saved a month helped them out.  A LOT!

To be fair, a lot of the people who bought into cheap solar did it, as your people did, to be green, to tell their friends, etc.  Basically they did it out of guilt.

Plastic conduit.  We would be red tagged for that crap in California.  Not to mention, in 5 to 10 years, plastic pvc conduit falls apart, looks like holy hell with sags between every support and it cracking and peeling away.

I'd honestly make a purchase contingency on someone removing the plasdick pipe and putting emt up there.   Emt will do double duty and give you a secondary bond, if done right.

--Shane
KD6VXI

I can see how being able to finance the solar would be helpful for folks. The savings on their system was A$40 a year, not per month.

My problem is the company is unwilling to refit the system to make it quieter, or let me do it or do anything to it. We ended up walking away from the deal for that and other reasons. We're zeroing in on a place nearby with half as many acres, rhombics are probably not an option with the layout unless I want to go north-south, but I should be able to setup some nice beverages and other antennas. A neighbor has a solar system about 500' away which I hope won't be an issue. A quick listen with the mobile didn't seem to show any issues but I'll get a better listen next week.

If it comes to pass, I'll be shooting wires into the trees in January, prime antenna weather. :-)

Thanks for all the help trying to sort that location and system.

Maybe this will make you feel better about no rhombics: https://www.w8ji.com/rhombic_antennas.htm

Thanks, it did. Not that Rhombics were really a desire - just a whim based on the possibility of significant space around a possible new QTH.

"the company is unwilling to refit the system to make it quieter"
So if they are made aware of the problem, and that their equipment is causing interference to an FCC licensed radio service, you think that might motivate them?

When I notified my local power company that bad insulators were causing a lot of RF interference on 160 / 75 they told me they would investigate, but it would take 3-6 months! I sent them a letter informing them again, making it clear that I'd follow up with the FCC. It was fixed within 1 week!

Umm, based on my interactions with them, no. Unless someone from the FCC was pushing them or threatening fines, my take is they would just ignore the problem in hopes I'd go away.

The power company may have more experience with the FCC. These folks just didn't seem to give a rip.