Starting system design for EG4 18kpv grid tied w/ net metering + battery setup

[FilterGuy]

I looked into this a little bit.

• The solar edge optimizers have built-in RSD.
• To get the optimizer's RSD function to work properly, they must be connected to either a Solar Edge inverter or a solar edge SMI (Safety and Monitoring Interface) device. (If you are familiar with Tigo CCA, the SMI is very similar.) The SMI will keep a constant communication with the Optimizers and if the communication ever stops, the optimizers initiate a RSD function. The communication is a proprietary format, so Sunspec transmitters will not keep them alive)
• The SMI not only controls the RSD function, but it also provides panel-level data through its onboard screen as well as over the internet. (The Tigo CCA only provides data over the internet)
• The SMI is powered by AC. They want you to plug the AC into the output of the inverter so if the inverter goes into an RSD state and shuts down, the SMI turns off and the optimizers go into an RSD state.
• If you want the solar edge optimizers to operate without the SMI or SE inverter, you can use the Solar Edge Key to disable the RSD function of the optimizers. Once the function is disabled, the optimizers will no longer go into the RSD state if communication is lost.

So, you can use the key to disable the RSD function or you can use an SDI to preserve the RSD function.

HOWEVER: Setting up the SDI will create the possibility of a dark start scenario: If the inverter shuts down during a power outage due to low battery, the SMI will be shut down. When that happens, the optimizers will go into their RSD function so the solar is no longer able to charge the batteries. I do not know of a workaround for this. (The Tigo CCA is powered by 12-24V DC and that allows a workaround when using the 18Kpv)

 

[zanydroid]

If the SMI does not exist in the US, is there a third-party SE clone for RSD transmitter?

That would be in a dubious state wrt code compliance since there's some verbiage in code about the system being listed. But it's better than disabling RSD.

 

[y0bailey]

Thanks for the additional digging guys.

I'm going the key route and disabling safe DC, but I'm not sure this sketchy overseas website will ever actually deliver my purchase.

So I have that timeframe to see if there are any third party options out there... But it seems unlikely.

Worst case scenario I have the key to disable safe DC on the ground mount panels and I have fewer optimizers to swap to maintain roof mount RSD.

 

[Mkillmer]

*I will have to dig around to find the service rating on the panel. I will report back in.

*The splices are copper/aluminum rated. I will double check every other other connection point.

*I believe when using the SolarEdge Key to make the Solaredge optimizers compatible with the EG4 inverter I will be removing their built in rapid shutdown capability.


As far as "needing" a rapid shutdown initiator outdoor...I don't know the answer to that. I haven't researched this yet, but seeing as I don't want to burn my family alive and would like to save things in case of fire, I am going to start research here and plan to install one.

I also don't know the requirements for the AC/PV disconnects. I am assuming they are needed outdoors based on the professionally done SolarEdge setup having both. The current plan has the PV disconnect outside, but the AC disconnect will be located in the basement. However, the 200A outdoor panel/utility breaker is "grid side" to the solar setup...so things can be easily cutoff from the exterior of the house. I'm sure there are code requirements here I may not meet...but I am not going to move from this house EVER, so I'm not going to lose a lot of sleep over that aspect. I mostly just care if the choice is UNSAFE for my family.


I hugely appreciate the response. It's nice to know my general plan is sound with a few tweaks here and there required.

Where can I get a solaredge key

 

[Mkillmer]

Thanks for the additional digging guys.

I'm going the key route and disabling safe DC, but I'm not sure this sketchy overseas website will ever actually deliver my purchase.

So I have that timeframe to see if there are any third party options out there... But it seems unlikely.

Worst case scenario I have the key to disable safe DC on the ground mount panels and I have fewer optimizers to swap to maintain roof mount RSD.

Did you ever get the solar edge key?

 

[y0bailey]

Where can I get a solaredge key

You can't. I am now going the AC coupling route.

They are no longer made by SolarEdge, they aren't for sale in the US, and my overseas quest results in me having to get my money back through my credit card company.

I've sent messages on reddit to the one guy that had one, no response.

I've tried everything I can think of. Save your energy.

 

[Mkillmer]

You can't. I am now going the AC coupling route.

They are no longer made by SolarEdge, they aren't for sale in the US, and my overseas quest results in me having to get my money back through my credit card company.

I've sent messages on reddit to the one guy that had one, no response.

I've tried everything I can think of. Save your energy.

I am somewhat new. What is involved in ac coupling. My inverter has gen input and ac input which is not used because I am off grid

 

[zanydroid]

There’s a AliExpress seller that is hard coding ostensibly SE optimizers to disable 1V mode and to force an output voltage. A forum member has a stack of these to do DC voltage level shift of their panels. It works and they only cost $25 apiece. Hahaha.

So someone has either a Key or likely more advanced tool with PLC control over SE, but you might literally have to learn Chinese and dive into their darkweb /s to figure out what the secret sauce is.

 

[Mkillmer]

Well. Hopefully someone on this site has a key as I have seen claimed. And might offer this service.

 

[zanydroid]

Even if you get the optimizer unlocked, there are a lot of configs that probably don’t work, and the SE behavior is poorly documented in a lot of situations I would personally be interested in.

I would HIGHLY recommend creating your own thread describing what you have now and what you’d like to do. Because you could easily be going down a rathole that nobody can fix without being an engineer working at SE or an incredibly talented low level hardware hacker.

 

[Mkillmer]

Only wanted to put them into independent operation for any inverter and to be used in shady areas. Mountains has lots of trees

 

[zanydroid]

TIGO optimizer and be satisfied with what you can get vs a more advanced optimizer, or wait a year for SolArk’s optimizer to be rolled out and understood by the community.

Or Microinverters into an storage inverter via AC coupling. I recommend searching forum for AC coupling and coming back with questions, with your vague description of goals it’s hard to focus answers explaining AC coupling to your specific knowledge level and problem to solve.

Also the solution to trees is to not have them in the way. I struggle with them on my property and the sad truth is that any non-simple shading wrecks your ROI. I use microinverters on grid for now and will try AC coupling next with my hybrid upgrade, whenever that happens. TIGO was too many compromises. SE was $$$ and really terrible interoperability at the DC level

 

[y0bailey]

I did this research for hours. You are screwed. They discontinued the key and the monitoring module backup plan.

I would focus your energy on AC coupling. I was intimidated by it originally, and the thought of two inverters that can fail is a bummer...but it's really the only way to keep me from having to climb on a 3rd story roof and swap optimizers...and have significant complexity with needing TIGO optimizers/monitoring equipment in two locations (roof and ground mount), new wire runs to the ground mounts would require digging...and it just was not worth it.

AC coupling is as easy as taking the AC out wires from the SolarEdge and running it to the GEN port on the 18kpv...then a couple settings to adjust in the 18kpv.

The SE inverter was easy to place in Rule 21 mode using SetApp, so once I'm up and running I can see how the frequency shifting goes. Still waiting on my 18kpv and battery to ship, so I'm stuck in a holding pattern.

 

[zanydroid]

That sounds about right with my analysis as a backseat driver on this.

 

[wolfmansbrother]

I did this research for hours. You are screwed. They discontinued the key and the monitoring module backup plan.

I would focus your energy on AC coupling. I was intimidated by it originally, and the thought of two inverters that can fail is a bummer...but it's really the only way to keep me from having to climb on a 3rd story roof and swap optimizers...and have significant complexity with needing TIGO optimizers/monitoring equipment in two locations (roof and ground mount), new wire runs to the ground mounts would require digging...and it just was not worth it.

AC coupling is as easy as taking the AC out wires from the SolarEdge and running it to the GEN port on the 18kpv...then a couple settings to adjust in the 18kpv.

The SE inverter was easy to place in Rule 21 mode using SetApp, so once I'm up and running I can see how the frequency shifting goes. Still waiting on my 18kpv and battery to ship, so I'm stuck in a holding pattern.

I'm about ready to wire my SE inverter to my 18K for AC coupling. I don't have a SetApp login not sure that matters, but I can connect directly to the wifi. it's set to ISO-NE 240v now, so just change to the Rule 21 240v Grid, anything else? I'm looking to get some off grid testing done while in full sun to see it in action and make sure no magic smoke gets released. My SE1400H is easily maxed out in clear skies this time of year.

 

[y0bailey]

I'm about ready to wire my SE inverter to my 18K for AC coupling. I don't have a SetApp login not sure that matters, but I can connect directly to the wifi. it's set to ISO-NE 240v now, so just change to the Rule 21 240v Grid, anything else? I'm looking to get some off grid testing done while in full sun to see it in action and make sure no magic smoke gets released. My SE1400H is easily maxed out in clear skies this time of year.

If you can change it to rule 21 you should be good to go. I worry you will need setapp to do that but hopefully not

 

[wolfmansbrother]

If you can change it to rule 21 you should be good to go. I worry you will need setapp to do that but hopefully not

Ok, thanks. based on this post it seems SetApp adds firmware updates, but SE support over chat was able to update my firmware remotely. They didn't seem keen on granting me SetApp access, so maybe their process changed, they told me to contact my installer. The local WiFi method seems to expose all the same settings, it's just less convenient.

 

[y0bailey]

Ok, thanks. based on this post it seems SetApp adds firmware updates, but SE support over chat was able to update my firmware remotely. They didn't seem keen on granting me SetApp access, so maybe their process changed, they told me to contact my installer. The local WiFi method seems to expose all the same settings, it's just less convenient.

I'm just not sure you can change them there... But maybe so.

You can bypass the setapp registration through solar edge website. I forget the exact details.

You just say you are an installer, make a different user name using a different email... And if I remember correctly you just leave something pretty important blank/unanswered and then you can get in.
It's been months and I can't remember the specifics

 

[wolfmansbrother]

I'm just not sure you can change them there... But maybe so.

You can bypass the setapp registration through solar edge website. I forget the exact details.

You just say you are an installer, make a different user name using a different email... And if I remember correctly you just leave something pretty important blank/unanswered and then you can get in.
It's been months and I can't remember the specifics

I was able to use the local wifi, change the grid successfully and charge up the batteries today from my SE 11k AC coupled, so that's neat. However, now I think I'm missing another setting because when I shut the grid input off, my SE status page reported "Error 3x6E: Meter Communication Error" and shutdown within a few minutes... the 18K stayed on, obviously it reported zero input grid and AC coupled solar.

 

[y0bailey]

I was able to use the local wifi, change the grid successfully and charge up the batteries today from my SE 11k AC coupled, so that's neat. However, now I think I'm missing another setting because when I shut the grid input off, my SE status page reported "Error 3x6E: Meter Communication Error" and shutdown within a few minutes... the 18K stayed on, obviously it reported zero input grid and AC coupled solar.

If your batteries were full that may be the "correct" series of events.

The 18kpv will have a setting for when to enable/disable AC coupling. If your battery is above that cutoff, it will frequency shift and shut down the SE inverter (to protect the battery). Not sure if the SE inverter handled it properly, but cutting itself off when above a battery SOC% is the correct way to protect your setup.