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An Approaching RF Shinola Storm?




 
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KD6VXI
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« Reply #25 on: June 19, 2018, 07:25:21 PM »

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
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WA2SQQ
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« Reply #26 on: June 20, 2018, 09:39:32 AM »

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.
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KD6VXI
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« Reply #27 on: June 20, 2018, 11:45:00 AM »

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
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K6JEK
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« Reply #28 on: June 27, 2018, 04:05:28 PM »

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?
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KD6VXI
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« Reply #29 on: June 27, 2018, 10:37:15 PM »

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
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W1RKW
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« Reply #30 on: August 03, 2018, 03:53:49 PM »

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.
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« Reply #31 on: August 04, 2018, 06:28:08 PM »

Indeed heat and reflection of the light not absorbed. Energy cant't be lost.
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« Reply #32 on: August 05, 2018, 09:09:05 AM »

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?
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« Reply #33 on: August 08, 2018, 02:53:53 PM »

Quote
if a solar panel for example is about 20% efficient in converting light into DC, what is the other 80%?

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?
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« Reply #34 on: August 08, 2018, 04:00:40 PM »

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.
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WB2EMS
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« Reply #35 on: August 09, 2018, 11:25:54 AM »

Quote
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

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.

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73 de Kevin, WB2EMS
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« Reply #36 on: August 09, 2018, 12:08:41 PM »

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
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AJ1G
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« Reply #37 on: August 10, 2018, 07:12:17 AM »

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.
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Chris, AJ1G
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« Reply #38 on: August 10, 2018, 08:37:34 AM »

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.




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?

Looks like these 2 solar installations are pretty quiet..   That is a good thing
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« Reply #39 on: August 12, 2018, 11:02:19 AM »

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
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« Reply #40 on: August 12, 2018, 06:28:08 PM »

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
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Tom W2ILA
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« Reply #41 on: August 12, 2018, 08:28:13 PM »

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
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AJ1G
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« Reply #42 on: August 13, 2018, 06:39:42 AM »

[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.
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« Reply #43 on: August 13, 2018, 07:50:44 AM »

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.
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« Reply #44 on: August 13, 2018, 09:59:38 AM »

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.
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KD6VXI
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« Reply #45 on: August 13, 2018, 11:05:20 PM »

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
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* Sweep of LED EMI filter.jpg (114.93 KB, 892x823 - viewed 45 times.)

* 20180813_195901.jpg (3572.51 KB, 4160x3120 - viewed 51 times.)

* 20180813_195730.jpg (4029.37 KB, 4160x3120 - viewed 46 times.)
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KD6VXI
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« Reply #46 on: August 13, 2018, 11:41:03 PM »

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
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« Reply #47 on: August 14, 2018, 10:09:46 AM »

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
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« Reply #48 on: August 14, 2018, 07:59:57 PM »

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
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« Reply #49 on: October 09, 2018, 02:42:49 PM »

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.  Shocked  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.  Cheesy   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.


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73 de Kevin, WB2EMS
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