Rapid Shutdown (RSD) on the EG4 18Kpv

FilterGuy

Solar Engineering Consultant - EG4 and Consumers
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I have been investigating Rapid Shutdown on the 18Kpv and would like to offer some clarity on the capabilities and situation.

1) The 18Kpv can do rapid shutdown out of the box using the integrated Rapid Shutdown Initiator. When triggered, the inverter will shut down the AC output and the PV (Shutdown of the PV requires a Sunspec Compliant RSD receiver on the PV panels.)

2) A remote Initiator can be installed on the 18Kpv. EG4 has published a white paper on how to do this. The white paper can be found at:
https://eg4electronics.com/wp-content/uploads/2023/08/External-RSD-Switch-Install-v1.01.pdf

The engineers at EG4 tell me that within a few days, all new shipments of the 18Kpvs will include the ‘Green Connector’ that the paper mentions. In addition, I have been told that Signature Solar Technical support is setting up a process to ship a connector to existing 18Kpv owners on request.

Note: The ‘Green Connector’ mentioned in the paper is not strictly required. However, it simplifies the process because it does not require special crimp or soldering tools.

3) The presence of a PV rapid shutdown system can cause a ‘dark start’ problem if the inverter shuts down when the batteries get low. (The 18Kpv with Sunspec-compliant receivers do not have this issue.) However, when using Tigo Optimizers with the Tigo Cloud Connect Advanced, a dark start problem can happen if the CCA is powered by the Inverter AC output as instructed in the CCA manual. The paper referenced above gives a solution to this problem that was developed by EG4.

Note: There are other optimizers such as the Solar Edge that do not have a known solution to the dark start problem. Take care when selecting your components.
 
Can you use this to only shut down the AC output? My solar panels are on the shop so separate building from the house and I already have emergency disconnects for those. If I go with a couple of the 18kpv units in the detached garage (with a covered breezeway so it's not completely detached) to replace the LV6548s I have, I'd like to have a way to shut down the inverters from outside the garage. No code compliance issues out here in the country but I recognize the importance, especially for fire emergencies. I realize the DC disconnects would only protect from there to the inverters so the solar panels would still be hot, but with those on the shop it shouldn't be as critical. Or maybe I'm looking at it all wrong and need more education. That never surprises me. ?

Also, with two of the inverters would I need two exterior shutdown buttons?
 
Can you use this to only shut down the AC output?
Yes. I assume your panels don't have Sunspec-compliant receivers so when you hit the switch the inverter will shut down but nothing will happen on the PV.
Also, with two of the inverters would I need two exterior shutdown buttons?
Good question. At a minimum, you could use an initiator with two NC switches so they both open at the same time.
 
I have been investigating Rapid Shutdown on the 18Kpv and would like to offer some clarity on the capabilities and situation.

1) The 18Kpv can do rapid shutdown out of the box using the integrated Rapid Shutdown Initiator. When triggered, the inverter will shut down the AC output and the PV (Shutdown of the PV requires a Sunspec Compliant RSD receiver on the PV panels.)

2) A remote Initiator can be installed on the 18Kpv. EG4 has published a white paper on how to do this. The white paper can be found at:
https://eg4electronics.com/wp-content/uploads/2023/08/External-RSD-Switch-Install-v1.01.pdf

The engineers at EG4 tell me that within a few days, all new shipments of the 18Kpvs will include the ‘Green Connector’ that the paper mentions. In addition, I have been told that Signature Solar Technical support is setting up a process to ship a connector to existing 18Kpv owners on request.

Note: The ‘Green Connector’ mentioned in the paper is not strictly required. However, it simplifies the process because it does not require special crimp or soldering tools.

3) The presence of a PV rapid shutdown system can cause a ‘dark start’ problem if the inverter shuts down when the batteries get low. (The 18Kpv with Sunspec-compliant receivers do not have this issue.) However, when using Tigo Optimizers with the Tigo Cloud Connect Advanced, a dark start problem can happen if the CCA is powered by the Inverter AC output as instructed in the CCA manual. The paper referenced above gives a solution to this problem that was developed by EG4.

Note: There are other optimizers such as the Solar Edge that do not have a known solution to the dark start problem. Take care when selecting your components.
I need a little clarification please. I have solar edge optimizers and plan to use the 18kpv in a whole home, grid tie, battery configuration. I know I can AC couple with my current solar edge grid tie inverter but I would rather remove it completely. If I have grid connected to grid, main panel connected to load, battery to battery and panels to PC is there anything special I need to do for the system to work with my solar edge optimizers? I hope that word salad makes sense.
 
The solaredge optimizers will only work with their inverter, they don't talk to anything else. You either need to keep your solaredge inverter with the optimizers and AC couple it or remove them and either connect your panels direct to the inverter or use the tigo rapid shutdown devices if required by code, if you are going to follow code.
 
The solaredge optimizers will only work with their inverter, they don't talk to anything else.
Not quite true.

* There is a device that Solar Edge sells that will completely turn off the RSD function of the Solar Edge Optimizers. (I think it is called the Solar Edge Key). However... if you need RSD you will be out of luck.

* Solar edge does sell a controller that works with the optimizer. If you remove power from the controller, the optimizers will initiate a rapid shutdown sequence. The only downside is that the controller requires 120V power supply... so you have to plug it into the output of the 18K to make it all work. (When the 18K does a Rapid shutdown the AC turns off which initiates a rapid shutdown of the optimizers. That works OK but it introduces a greater possibility of a dark start problem. Here is the dark start sequence:

The inverter is powering the load overnight (No Grid power).
The batteries get low enough that the inverter shuts down
The Solar Edge optimizers shut down.
In the morning the panels can't turn on to charge the batteries.

With the Tigo optimizers and associated CCA controller, the CCA can be powered from the +/- 12V power supply the 18Kpv offers. This power supply will remain on till the batteries shut down.... even if the batteries get low enough that the inverter shuts the AC down.
 
Basically a Europe only thing, I looked into it and I cannot get the key in the USA and I think you lose RSD as well.
I have 45 optimizers and a 10K unit but ultimately I decided it was just too much fannying around to reuse those again. Believe me I would have if I thought it was worth it because I'm cheap. They could still be used for a system that does not need to be inspected easily.
 
Not quite true.

* There is a device that Solar Edge sells that will completely turn off the RSD function of the Solar Edge Optimizers. (I think it is called the Solar Edge Key). However... if you need RSD you will be out of luck.

* Solar edge does sell a controller that works with the optimizer. If you remove power from the controller, the optimizers will initiate a rapid shutdown sequence. The only downside is that the controller requires 120V power supply... so you have to plug it into the output of the 18K to make it all work. (When the 18K does a Rapid shutdown the AC turns off which initiates a rapid shutdown of the optimizers. That works OK but it introduces a greater possibility of a dark start problem. Here is the dark start sequence:

The inverter is powering the load overnight (No Grid power).
The batteries get low enough that the inverter shuts down
The Solar Edge optimizers shut down.
In the morning the panels can't turn on to charge the batteries.

With the Tigo optimizers and associated CCA controller, the CCA can be powered from the +/- 12V power supply the 18Kpv offers. This power supply will remain on till the batteries shut down.... even if the batteries get low enough that the inverter shuts the AC down.
Do you have any info on the controller? If all it needs is 120v that wouldn't be an issue. I will have the grid connected so a dark start shouldn't be an issue.
 
Not quite true.

* There is a device that Solar Edge sells that will completely turn off the RSD function of the Solar Edge Optimizers. (I think it is called the Solar Edge Key). However... if you need RSD you will be out of luck.

* Solar edge does sell a controller that works with the optimizer. If you remove power from the controller, the optimizers will initiate a rapid shutdown sequence. The only downside is that the controller requires 120V power supply... so you have to plug it into the output of the 18K to make it all work. (When the 18K does a Rapid shutdown the AC turns off which initiates a rapid shutdown of the optimizers. That works OK but it introduces a greater possibility of a dark start problem. Here is the dark start sequence:

The inverter is powering the load overnight (No Grid power).
The batteries get low enough that the inverter shuts down
The Solar Edge optimizers shut down.
In the morning the panels can't turn on to charge the batteries.

With the Tigo optimizers and associated CCA controller, the CCA can be powered from the +/- 12V power supply the 18Kpv offers. This power supply will remain on till the batteries shut down.... even if the batteries get low enough that the inverter shuts the AC down.
I've been digging all morning and I think I found what you are referring to. It looks like I need their SMI. Only problem is I can't find where to buy one. I very much appreciate all the help. If anyone knows where I can get a Solar Edge SMI that would be great.
Search for Solar Edge SMI (Safety and Monitoring Interface)
Now I just need to find out where to get one.
 
Do you have any info on the controller? If all it needs is 120v that wouldn't be an issue. I will have the grid connected so a dark start shouldn't be an issue.
Something to consider:

The most likely reason you'd run your batteries down to the point where your inverter were to shutoff, would be due to a grid outage.
If that is the case, the grid isn't going to resolve the "dark start" issue for you, until it returns. Thus, you may still want to consider some "dark start" options that don't involve the grid.

IMO: "dark start" solutions that involve "grid" in the sentence, aren't a solution. chicken and egg scenario.
 
What happens if you have three 18kPVs in parallel and one RSD NC switch? Can you just connect to the master unit or do you have to connect to all three inverters? If you need to connect each inverter, what would the wiring look like for that? BTW I also will not be shutting down the PV only the AC output.
 
Hi,

I am about to order either the EG4 18k or the Sol-Ark 15k (still weighing cost benefit here), but in either case I will have three DC solar strings and additional AC coupled solar. The three solar strings will have zero shading issues and are setup such that i really dont need optimization. that said, with the sol-ark i was going to go with their optimizers as the cost increment over RSD devices is worth it for panel level monitoring (I'm used to it with my current microinverter system).

However, I don't have any code issues that require RSD devices at all, so the question is, do I really need them? Skipping all together would save me a lot of money on 34 panels and make installation a lot simpler. Is the upside of RSD devices increased fire protection, increased safety for first responders, or both? For fire protection, I can see the benefit of having a system that turns off the DC current at the roof automatically if an arc is detected in the feed wires. Though I'm not even sure they do this?

Alex
 
My neighbor and I have 3 independent Sol-Ark 15K on the property. My dark start solution will be to run an extension cord from the TIGO CCA power supply to a different building. Two new Sol-Arks went live yesterday.
 
My dark start solution is multi-pronged.

#1) I have a 48v to 12v buck converter. If my inverter shuts down, I can power the tigo CCA from the 48v battery bank
#2) If that battery bank is somehow completely dead, I have a small 6AH lipo4 battery for my ham radios. I've got a 30a anderson plug on it, and an anderson plug on my CCA. so, I can just connect it and power the CCA.
#3) I have a 12v cigarette lighter adapter cord with the same 30a anderson plugs. If needed, I can take the CCA out to my truck, and power it from that battery
#4) I have a small 30w solar panel and 2 12v batteries on an electric gate opener. I've added a 30a anderson powerpole to that battery as well. Once again, just walk the CCA over to it, and plug it in.

#5) And worst case solution: I can bypass the tigo modules on 4 or 5 panels, and let them recharge the 48v battery bank until the inverter powers back on.


My CCA is close enough to the arrays, that I didn't need to put the TAP on the roof. So, my CCA and TAP are about 1' apart. Which makes it super easy to move to a truck, or gate opener, or something all as a complete package.
 
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My dark start (black start) solution looks like this:

All my PV modules are connected via Tigo-4-2F modules (each of this Tigo device can handle 2 PV modules) to implement a module-level-PVRSS via the Tigo RSS Transmitter. If the RSS transmitter does not have power, PV energy is just not available because the arrays are disconnected.

For dark start situations, I feed a controller circuit which powers the Tigo RSS transmitter via a relay (beside other NO relays/contactors to control my solar system) with a small pure sine wave UPS (about $150, 108Wh, 1000VA/600W). This UPS is connected to an existing power outlet in the garage beside the inverters and get's automatically charged and it's SOC stays usually at 100%. In case of an emergency shutdown the mini UPS could provide about 1h-2h power to my controller circuit to drive the relays which makes it possible to do a dark start.

In the unlikely case this mini UPS would be empty, I may charge it either via my motorhome power outlet via an extension cord or a small generator, etc.

In case of an emergency, my controller does disconnect the batteries (via two 600A DC relays) , the AC-in's (via 110A AC contactors) and the PV modules (via Tigo RSS). All of this relays are NO (normaly open) which is the reason why I need a dark start solution anyway, not only for emergency but even for system startup. I've decided that using a cheap mini UPS would be perfect for my situation.
 
I'm looking for information on how to safely shut down my DC coupled PV array with the 18kpv.

I have an IMO disconnect outside by the panels, and obviously the 18kpv has the shut down on the outside of the enclosure, but what is the best way to shut down my array if it's mid day and I need to work on something?

I know this is a dumb question, I just want to keep my equipment and myself safe!
 
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