Is it possible to protect your Solar System against EMP?

[Sanwizard]

I assume the inverter, SCCs and electronics are mounted to a wall ... will you build the cage in behind the equiptment? or just on 5 sides with the wall side not being in the cage?

When I built the wall, I included a thin metal layer on the outside, and put up metal screen mesh behind all the equipment. The batteries will be in the metal rack, and enclosed with screen wire mesh around that also.

 

[Hedges]

Faraday cage wrapped around electronics and closed without large gaps should attenuate EM fields.
All wires leading in would need filters capable of blocking the energy without saturating. I don't believe ferrite per wire is capable of that.
Ferrites as common-mode chokes around pairs of wires can block common-mode, up to the signal level where saturation occurs.

Long power lines pick up single-ended and common mode well below 60 Hz. No inductive chokes would be able to stop that. The main effect is applying near DC to transformers, which saturates them so available AC power burns them out. Short wires of an off-grid system (not hundreds or thousands of miles) wouldn't pick up such low frequencies.

A motor-generator, with coupling grounded by brushes/slip rings, would be one way to transfer power through a faraday cage.

A hostile EMP generated with high altitude device near Canadian border would only subject a prepper's system to some effects, different from what weapons systems would see when the other sides detonates something close to them. I've read about the low frequencies affecting power lines, and vehicles & portable radios that only get higher frequenies.

SolArk I think wrote about their in-house tests with conducted waveforms from PV wires into SCC; some brands were damaged. Have to consider what waveforms and amplitude are applicable for your location. The loop area of PV wiring and panels would be key, and you may be able to make it "twisted" rather than a larger loop. Then devices like MOV or TVS to protect electronics, line to line and line to ground. That would be what SolArk does. Good for nearby lightning, a much more likely event especially in some regions.

 

[Marcaroni]

Store BMS entirely disconnected from battery.
Most damage due to "events" occurs because event triggers flow of current from connected power, burning things out.

Bad BMS is worse than no BMS, as it can drain cells. With its balancing circuitry, and as a load that consumes power (more if transistors shorted.)

Any battery can only be stored in some state of charge for so long before it degrades. Typically, periodic recharging to some SoC (100% of lead-acid, maybe 30% to 50% for lithium) gives longest shelf life.

Perhaps dry FLA batteries and separate sulfuric acid, possibly mixed in glass jar but better dry and sealed, would be best for decades of storage.

I don't think any disconnected battery will be harmed by EMP, nor if connected. Electronics and (with power available) transformers are at risk.

“Store batteries disconnected from batteries “? I thought they were part of the same unit. Thinking about SOK 5kwH rack/stackables. While we are here, how important/crucial is BMS? And if BMS no longer functions, will batteries function at all.

 

[Sanwizard]

Faraday cage wrapped around electronics and closed without large gaps should attenuate EM fields.
All wires leading in would need filters capable of blocking the energy without saturating. I don't believe ferrite per wire is capable of that.
Ferrites as common-mode chokes around pairs of wires can block common-mode, up to the signal level where saturation occurs.

Long power lines pick up single-ended and common mode well below 60 Hz. No inductive chokes would be able to stop that. The main effect is applying near DC to transformers, which saturates them so available AC power burns them out. Short wires of an off-grid system (not hundreds or thousands of miles) wouldn't pick up such low frequencies.

A motor-generator, with coupling grounded by brushes/slip rings, would be one way to transfer power through a faraday cage.

A hostile EMP generated with high altitude device near Canadian border would only subject a prepper's system to some effects, different from what weapons systems would see when the other sides detonates something close to them. I've read about the low frequencies affecting power lines, and vehicles & portable radios that only get higher frequenies.

SolArk I think wrote about their in-house tests with conducted waveforms from PV wires into SCC; some brands were damaged. Have to consider what waveforms and amplitude are applicable for your location. The loop area of PV wiring and panels would be key, and you may be able to make it "twisted" rather than a larger loop. Then devices like MOV or TVS to protect electronics, line to line and line to ground. That would be what SolArk does. Good for nearby lightning, a much more likely event especially in some regions.

Agree about the saturation issue. I am using the higher priced Fair-rite cores that are tested for high saturation. The ferrites from China are mostly crap.

 

[Sanwizard]

“Store batteries disconnected from batteries “? I thought they were part of the same unit. Thinking about SOK 5kwH rack/stackables. While we are here, how important/crucial is BMS? And if BMS no longer functions, will batteries function at all.

BMS is critical for Lithium batteries to protect the cells. Not needed for lead acid. If the BMS goes bad, it will most likely stop current flow. You can disconnect it in use the battery, but I would only do that in an emergency.

 

[Hedges]

“Store batteries disconnected from batteries “? I thought they were part of the same unit. Thinking about SOK 5kwH rack/stackables. While we are here, how important/crucial is BMS? And if BMS no longer functions, will batteries function at all.

Some people report operating lithium battery with no BMS. Living on borrowed time?

If storing lithium battery long term, maybe unplugging BMS from cells, leaving at most a single battery cable connected, would serve to protect against voltage/current induced by EM fields. Also eliminates drain powering electronics. Need to reconnect, check SoC and recharge as needed occasionally.

If pre-packaged, you might open to do this. Don't think warranty service available following Armageddon, anyway.

If I eventually use lithium, I will have BMS. I'll select one (presumably REC) compatible with my SI.

 

[Hedges]

Agree about the saturation issue. I am using the higher priced Fair-rite cores that are tested for high saturation. The ferrites from China are mostly crap.

No ferrite smaller than a 50 gallon garbage can is going to work for single 300A DC battery cable without saturating. Yet, I've heard of small clamp ferrite around a single AC wire being sufficient to pass an EMI test that failed previously, not sure exactly why (haven't modeled or calculated it.)

Easy to deal with common mode (interference much higher frequency or lower amplitude than fundamental differential signal.)
Differential mode, I think air core is about all that can help (because it doesn't saturate.) EMI filters often have 2-coil chokes, and "leakage inductance" is what helps with differential mode, like from SMPS. Working together with capacitors.

 

[Hedges]

BMS is critical for Lithium batteries to protect the cells. Not needed for lead acid. If the BMS goes bad, it will most likely stop current flow. You can disconnect it in use the battery, but I would only do that in an emergency.

Following an "event", BMS could decide to rebalance all cells by draining them to zero.
That's a reason to keep balance leads disconnected until after you hear zombies outside.

What are all the BMS connections? Positive battery cable through FET (if no contactor) plus sense leads to all cells and sense leads to shunt on negative?

Don't want any loops that can generate voltage in EM field and blow electronics. Unplug balance leads. Probably unplug shunt, but if it had high-value resistors in series, could sense voltage while limiting current to what protection diodes can handle.

So I suggest unplug all except maybe one high-current lead between cells and disconnect FET.

 

[Sanwizard]

Following an "event", BMS could decide to rebalance all cells by draining them to zero.
That's a reason to keep balance leads disconnected until after you hear zombies outside.

What are all the BMS connections? Positive battery cable through FET (if no contactor) plus sense leads to all cells and sense leads to shunt on negative?

Don't want any loops that can generate voltage in EM field and blow electronics. Unplug balance leads. Probably unplug shunt, but if it had high-value resistors in series, could sense voltage while limiting current to what protection diodes can handle.

So I suggest unplug all except maybe one high-current lead between cells and disconnect FET.

Unplugging may be an option if there is a heads up before an event, like a solar flare, and hopefully sirens before the blast. But if its a surprise, the system will most likely be in use.

 

[houseofancients]

I just saw I can get 4 x 1Gb SFP's for $64 on Amazon. Wow, prices have come down a bit on optical!
My business was Storage Area Networking and Fibre Channel, so I do have experience in that area, but in the Enterprise class gear. Any thoughts on a good 4 port residential optical ethernet switch that doesnt break the bank?

i'm using the 10g unifi 16 ports, but that is only because everything else is unfi too , and like the single pane for monitoring and configuration.
for the optics i can give a very positive upvote for fiberstore ( fs.com)
used them for years now, great compatibility ( even the lock cisco's and netapps)and relatively cheap

 

[Hedges]

Unplugging may be an option if there is a heads up before an event, like a solar flare, and hopefully sirens before the blast. But if its a surprise, the system will most likely be in use.

Those of you far smarter talk than me discuss complicated ways to protect your (operating) chargers and inverters, but I am going to put my components with circuitry in faraday cages, as my interest is solar is prep for Armageddon. As I understand, panels should survive an EMP and many batteries, as they have no circuitry.

But so many batteries have “BMS” (management systems), especially the LiPo , which means circuitry and EMP vulnerability. First, will such batteries function if their BMS circuitry disintegrates. I was thinking that the BMS is just monitoring, and not really affecting the flow of charge, that the battery terminal would go , without a break, into the storage apparatus. Comments?

Second, would other battery types be a better choice to withstand an EMP out of a faraday cage?

I took that to mean stored until SHTF, as opposed to operating.
Faraday Cage helps, but nothing is 100%.
Putting circuits into a less vulnerable/sensitive state can be part of the protection.

Hardened electronics can be designed so even if all transistors turn on, it doesn't self destruct. That is probably for other effects besides EMP, and if they occur, the electronics will be the least of your concerns. (but for the "warfighter", objective is he can continue to fight so long as his health allows, isn't stopped by malfunctioning equipment.)

 

[Marcaroni]

Some people report operating lithium battery with no BMS. Living on borrowed time?

If storing lithium battery long term, maybe unplugging BMS from cells, leaving at most a single battery cable connected, would serve to protect against voltage/current induced by EM fields. Also eliminates drain powering electronics. Need to reconnect, check SoC and recharge as needed occasionally.

If pre-packaged, you might open to do this. Don't think warranty service available following Armageddon, anyway.

If I eventually use lithium, I will have BMS. I'll select one (presumably REC) compatible with my SI.

Does anyone know of a lithium battery that has a separate BMS that can be removed. I was thinking about putting a second/back-up BMS In faraday cages, and use it after the EMP destroys the unprotected BMS —so I can use batteries now.

 

[Hedges]

Some of the BMS people use for DIY have a connector. Don't know if server-rack or drop-in assemblies do.
You could select a connector and install it yourself. If you watch the details carefully, you might select a BMS with such connectors, and add mating connectors wired correctly to built-in BMS.

People have replaced BMS in server racks for one reason or another.

While you're at it, consider EMP hardening the original BMS. MOV/TVS devices aren't terribly expensive. Route and twist cables to make them a poor loop antenna.

 

[EastTexCowboy]

I've read quite a bit on EMPs over the years and there's plenty of opinions but not much in the way of real world testing, mostly because it would be difficult to come up with a test environment that simulates a high altitude detonation. I suspect a CME is just as or more likely and there are a lot of unknowns there as well. What occurs to me when it comes to preparing for something like this is that even if you protect your solar setup, most of the stuff you would want to run on it would be fried anyway. Of course you could always put all THAT stuff in a faraday cage as well, but it turns into a vicious spiral. Don't get me wrong, I don't think it's a bad thing to be as self-sufficient as possible and as prepared for the unexpected as much as possible. But you can't prepare for every contingency so my thoughts are first prepare for the stuff you KNOW will happen, such as power outages. Then if you have the resources and inclination prepare for the things that PROBABLY will happen. I'll let you define that based on your own situation. Finally, if you want to go all in, prepare for the things that MIGHT happen. If you get the first step done you're way ahead of most people. I know the power goes out, the water goes off, we will get bad winters and bad summers and occasional hurricanes. I KNOW those will happen, so why wouldn't I be ready for it? I think everyone should be prepared for that kind of stuff at a minimum, but most don't.

My two cents anyway. An EMP or CME is definitely an interesting topic and I hope we never have to deal with the aftermath of any serious event of this nature. But if we do I hope I still have internet and this forum is up and running! ?

 

[Hedges]

Only electronics would be fried (and transformers connected to long transmission lines and a power plant.)
Almost all cars survived testing. Some handheld radios did, some did not.

Your electromechanical appliances that were not connected to grid will be fine. Grid connected potentially at risk, and electronic controls at risk.

So it would seem that protecting inverters and charge controllers is prudent. Nearby lightning is the most likely spike source.

For anything electromagnetic connected to the grid, fast fuses and breakers should protect against overheating due to current. TVS type devices could protect against insulation breakdown.

The military protects its systems. This isn't rocket science (actually, that's exactly what it is, and I are one) but either way it is just signals into RLC circuits. So long as you're far enough to avoid ionizing radiation. Anybody can analyze it with algebra, given a model of the electromagnetic threat.

 

[Vigilant24]

Another opinion: I would characterize an NEMP or a huge CME as a "low probability/high impact" event. I think there's a lot to be said for safely storing a small amount of essential electronics (SCC, inverters, radios, electronic instruments, some solar panels, etc) in a tight (if low tech/cheap) Faraday cage. Bring out when needed. I'd have some backups, because things will be unpredictable.
I don't think I'd have much confidence in protecting electronics that were up and running or (especially) connected to the grid. Having a small amount of essential hardware totally shielded will be less expensive, less trouble, and more reliable than trying to shield/isolate in-use equipment.
But, that's for my situation. Others may be in a different situation.

 

[Sanwizard]

Does anyone know of a lithium battery that has a separate BMS that can be removed. I was thinking about putting a second/back-up BMS In faraday cages, and use it after the EMP destroys the unprotected BMS —so I can use batteries now.

The Seplos DIY kits are built by you, so you can buy as many spares as you need.

 

[EastTexCowboy]

Only electronics would be fried (and transformers connected to long transmission lines and a power plant.)
Almost all cars survived testing. Some handheld radios did, some did not.

Your electromechanical appliances that were not connected to grid will be fine. Grid connected potentially at risk, and electronic controls at risk.

So it would seem that protecting inverters and charge controllers is prudent. Nearby lightning is the most likely spike source.

For anything electromagnetic connected to the grid, fast fuses and breakers should protect against overheating due to current. TVS type devices could protect against insulation breakdown.

The military protects its systems. This isn't rocket science (actually, that's exactly what it is, and I are one) but either way it is just signals into RLC circuits. So long as you're far enough to avoid ionizing radiation. Anybody can analyze it with algebra, given a model of the electromagnetic threat.

I don't disagree with any of this. But at least in part due to that last sentence, any model you have is still speculative to some extent. The first sentence says a lot as well - only electonics would be fried. That covers a pretty broad scope of equipment nowadays. I'm not saying it's a bad thing to try to prep for an EMP. I'm just saying I feel there are other potential events which are much more likely, even if not as catastrophic.

 

[EastTexCowboy]

Another opinion: I would characterize an NEMP or a huge CME as a "low probability/high impact" event. I think there's a lot to be said for safely storing a small amount of essential electronics (SCC, inverters, radios, electronic instruments, some solar panels, etc) in a tight (if low tech/cheap) Faraday cage. Bring out when needed. I'd have some backups, because things will be unpredictable.
I don't think I'd have much confidence in protecting electronics that were up and running or (especially) connected to the grid. Having a small amount of essential hardware totally shielded will be less expensive, less trouble, and more reliable than trying to shield/isolate in-use equipment.
But, that's for my situation. Others may be in a different situation.

That's pretty much where I'm at on this as well.

 

[Sanwizard]

That's pretty much where I'm at on this as well.

Yeah, all the testing in the world does not mean a thing until it hits for real. A small CME may only have a minor effect, but a direct hit nuke will make for a bad day.
If the crap hits the fan with nukes, there is a big ass target on my area anyway, so I will probably not feel a thing.
We can only prepare for what we have the ability to. Some metal screening(faraday cage), ferrites, surge suppression and lightning arrestors are all I can do, but its at least something.