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  #1  
Old 02-08-2012, 02:31 PM
OffGridLiving Male OffGridLiving is offline
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Default Solar Panels and EMPs

With all the stuff on TV lately about different SHTF scenarios, including Electro-Magnetic Pulse and its effect on the grid, will an EMP fry a Solar array? If so, is there anything that could be done to harden the panels against damage?
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Old 02-08-2012, 03:47 PM
grumble Male grumble is offline
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As a practical matter, there isn't much you can do to protect PV panels from EMP. The individual solar cells are just little diodes, like your LED flashlight, except backwards -- the LED used electricity to make light, the PV cell uses light to make electricity.

Protecting the cells completely would involve making a "Faraday cage" that would block the EMP's radiation. This could be a piece of copper screen that's well grounded or even tin foil. Problem being, the covering blocks sunlight.

How well the cells inside your panel are connected and their availability to a good ground is really the only practical way to protect your system. Unless, of course, you have time to put up a Faraday screen when you hear about a solar event that might damage electronics. If the EMP were to come from enemy action (high altitude nuclear burst), there isn't much you can do.

With the price of PV panels dropping, it might be worthwhile to just keep some spare panels stored in a well-grounded metal shed. All other components of a solar system can be protected fairly easily.
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Old 02-08-2012, 07:11 PM
Proud_Poppa Male Proud_Poppa is offline
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About the only thing you could do is keep a spare set of panels in a well grounded metal storage shed. Even better would be to bury a spare set of panels a foot or so underground....of course you would have to protect them from the weight and soil...etc. An old fashioned root cellar might be great for that!!

But yes, solar panels have a gazillion little silicon junctions that are all susceptible to EMP.
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Old 02-08-2012, 09:59 PM
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The reason an EMP event messes with the grid is because there's a huge amount of wire suspended in free space to collect the energy it causes. It's more of a voltage surge than a high current thing that resembles a static discharge. The more "antenna" you have to collect energy, the higher the surge. (voltage)

Personally, I don't believe such a surge would destroy panels but it could ruin charge controllers and possibly blocking diodes. Panels would handle the small current surge and pass the induced voltage to the wiring. Any surge collected by the frames/mounts of the panels should go to ground. (IF they're grounded to earth) If a surge makes it through the controller, the batteries would absorbe it. As the voltage increases, the internal resistance of batteries decreases and would basically shunt it out BUT you better have a fuse between the battery and the controller! If the controller gets blasted, it would create a dead short to the battery! It would be a good idea to have a fuse on the panel side of the controller also..

I don't believe a small, centralized system would have a big issue unless you have a bunch of wires strung around everywhere connected to your system. Don't forget phone lines, cable, ANY long wire that's connected to your house (utility) that comes from a pole.. Even fences..
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Old 02-09-2012, 01:15 PM
grumble Male grumble is offline
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Anything with a PN junction is subject to EMP damage. This includes diodes, transistors, and IC chips. The only way to protect semiconductors is to shield them from the radiation with a conducting cover that's well grounded. Even then, there's still a possibility of reverse EMF induced into the ground flowing "backwards" through the semiconductor.
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Old 02-09-2012, 09:45 PM
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Quote:
Originally Posted by grumble View Post
Anything with a PN junction is subject to EMP damage. This includes diodes, transistors, and IC chips. The only way to protect semiconductors is to shield them from the radiation with a conducting cover that's well grounded. Even then, there's still a possibility of reverse EMF induced into the ground flowing "backwards" through the semiconductor.
I totally agree. IF there's a path to a lower potential, the induced voltage is going to try to find it. The voltage will conduct or arc through anything in its path IF there is a complete circuit to the lower potential.

Look at a laptop computer setting on a non-conductive item, like a table, with no external connections to anything. Everything inside the computer is connect together in some fashion, be it through resistors, capacitors, transformers, ect. The whole circuit is as one with no connection to a lower potential and all componets have a common connection.

IF this computer was exposed to an EMP, the internal circuits are going to rise and fall in voltage as one with no place for the induced voltage to dissapate to. If it doesn't have anywhere to go to outside of the computer, there will not be any arcs or any abrupt discharges. Things throughout the circuit will rise and fall in voltage as one.

If this computer should happen to be connected to an outlet, LAN, router, or anything external, and experiences an EMP, now we have problems. We have a path to a different voltage potential. The induced voltage either collected by the computer itself or by the external connections is going to find a path through something, somewhere through the path of less resistance to the lowest potential wherever it may be at that moment. Arc, surge, poof..

Any small battery operated device is a complete circuit within itself. If it isn't connected to anything external or laying on a conductive surface, I doubt it would get damaged. Even a TV setting on a table with nothing connected to it and not plugged in would be fine, IMO..
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  #7  
Old 02-10-2012, 01:52 PM
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I am concerned about this too. Coronal Mass Ejections of whatever intensity, are predicted for the next year or more, during the high point of the sun's cycle. Makes me worry a lot about putting panels up.

I'm still doing wiring for solar, a massive amount of it. In the process, I'm fusing everything, everywhere. Fuses are cheap; solar components are not.
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Old 02-10-2012, 05:15 PM
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Wiki has a pretty good article on the subject:
http://en.wikipedia.org/wiki/Electromagnetic_pulse

One interesting comment:
"The damaging effects on orbiting satellites are usually due to other factors besides EMP. In the Starfish Prime nuclear test, most satellite damage was due to damage to the solar panels from satellites passing through radiation belts created by the high altitude nuclear explosion.[31]"

I haven't found anything that discusses the concept of an electrically isolated item being exposed to an EMP, and whether or not there would be a constant change of electrical potential, thus preventing any discharge across internal components. But, even though the EMP travels at about 90% - 95% of the speed of light, and the EMP wavefront would transverse an item in a matter of portions of a nanosecond, I don't know if that would preclude damage to the item or not. I used to have a job not too far from "The Trestle" run by Sandia labs to test EMP. When they were getting ready to make a "shot," they'd clear all vehicles from a distance of a few hundred yards to prevent damage to the electronics. In any event, given the choice to protect things from EMP or just unplug them, I'd think that protection would be the better course of action.
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Old 02-11-2012, 12:47 AM
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In outer space, there's no atmosphere to dissipate energy. The results would be much more severe than on earth. Atomsphere absorbs radio waves and an induced EMP wouldn't be much different.

If a nuclear blast in the sky that produces an EMP event is close enough to cause severe damage to electronics, it would be close enough to destroy everything anyway. Faraday away.. LOL..

The energy pulses that comes from the sun is decreased immensely traveling through our atomsphere before it gets to ground level. The grid takes a butt kickin' because of all of the wires strung out everywhere to collect the energy over a vast area. It's a matter of physics..

"When they were getting ready to make a "shot," they'd clear all vehicles from a distance of a few hundred yards to prevent damage to the electronics."
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Old 02-11-2012, 01:59 PM
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12V, you're about the last person I know that I'd want to get into a technical disagreement with. Please take a quick look at the Wiki link above, about what an EMP is, what causes it, and how it propagates.

The solar panels on satellites seem to be damaged by radiation, not EMP. EMP is more a phenomenon caused by the magnetic field of the Earth rather than an electrical surge caused by the source. Gamma rays passing through the magnetic field cause the electrical generation.

But, none of this directly answers the question of whether or not solar panels need extra protection from EMP. I never did find a good answer to that question.
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Old 02-11-2012, 11:48 PM
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Com'on, Grumble.. I'ma Hillbilly that doesn't like to type a bunch. Gimmie a break.., LOL..

Personally, I'm not worried about what happens in space. Me worries about my back yard!

I know what EMP is.. Quote Wiki..

"An electromagnetic pulse (sometimes abbreviated EMP) is a burst of electromagnetic radiation. The abrupt pulse of electromagnetic radiation usually results from certain types of high energy explosions, especially a nuclear explosion, or from a suddenly fluctuating magnetic field. The resulting rapidly changing electric fields and magnetic fields may couple with electrical/electronic systems to produce damaging current and voltage surges."

And, If you're close enough to an explosive detonation for the gamma rays to gitcha, EMP ain't gonna matter..

I don't care about gamma rays knockin' electrons from atoms and all that stuff. My concern and focus is what happens AFTER all of that crap.

The link that you posted is there for all to read. All of that stuff is far out of the reach of anyone that has to deal with the aftermath. (I disassembled my jumbo gamma ray deflector to build a flux capactor.. Dangit..)

The bottom line is after a big boom-boom goes off in the sky, a magnetic pulse is gonna come rainin' down on us all and it "could" fry stuff. The closer to ground zero, the stronger the pulse. This magnetic pulse will induce or create movement in electrons in any "conductive" material and create voltage/current. The same theroy as a generator by passing a magnet by/through a coil of wire..

Elementary stuff here. The stronger the magnet, the speed it is traveling, and the amount of coil (in length of wire) will determine the induced voltage/current. How much wire does the grid involve? How much area does it cover? You can bet your sweet bippie I don't wanna be plugged in when it happens!

Now, for your concern..

"But, none of this directly answers the question of whether or not solar panels need extra protection from EMP. I never did find a good answer to that question."

Quote.. Wiki..

"The E1 pulse is the very fast component of nuclear EMP. The E1 component is a very brief but intense electromagnetic field that can quickly induce very high voltages in electrical conductors. The E1 component causes most of its damage by causing electrical breakdown voltages to be exceeded. E1 is the component that can destroy computers and communications equipment and it changes too quickly for ordinary lightning protectors to provide effective protection against it."

Soo.. In short, who knows? The facts are all about how much wire is connected to them and the level of voltage induced, and depending on how close to ground zero and South of detonation one is. I'm sure the controller would get fried before the panels. Most panels will handle a much higher voltage than the controller will..
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Old 02-12-2012, 12:47 AM
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Although EMP gets a lot of attention it's way down the list of things on my radar. It's not feasible to protect against every risk and even if it were, the cost would be prohibitive.

Perhaps if solar panels were well grounded against lightning strike they would be reasonably immune to a pulse? More likely, the panels survive better than the controller.

Simplest and perhaps most effective solution would be to have a backup controller and other sensitive parts.

And then hail the size of baseballs began to fall. . . .
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Old 02-12-2012, 01:06 AM
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If this stuff travels faster than lightning, we's in trouble!

http://www.lightningsafety.com/nlsi_lhm/lpts.html

As for lightning..

" ..and speeds approaching one third the speed of light."

And the "Unknowns"..

"In all instances, use high quality, high speed, self-diagnosing protective components. Transient limiting devices may use a combination of arc gap diverters-metal oxide varistor-silicon avalanche diode technologies. Hybrid devices, using a combination of these technologies, are preferred. Know your clamping voltage requirements. Confirm that your vendor's products have been tested to rigid ANSI/IEEE/ISO9000 test standards. Avoid low-priced, bargain products which proliferate the market."

Protect panels? All I can say is keep your wiring as short as possible. (Which ya should anyway)
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