How to AC couple Enphase IQ8 w/Battery Storage to Schneider XW Pro 6848 w/rack batteries, off-grid?

[solar8484]

My Solar Edge inverter is happy as a clam to AC couple to the Schneider XW pro. The issue is on the Enphase side, in my opinion.

Agreed but if I called Schneider sales today and asked them if the XW Pro can AC couple with Enphase what do you think they will tell me?

 

[wheisenburg]

A common thread in backup systems which can successfully AC couple with IQ8's is the PV disconnect relay:
IQ systems controller 1 (no relay) versus IQ system controller 2 (has 64 A PV relay)
FrankinWH aGate (has a 64 A PV relay)
CSI EP Cube (has 2 relay-controlled extension ports)

solar8484: The name plate UL listing is UL 1741SA. The firmware upgrade can upgrade them UL1741SB, and that is controlled by Enphase.
Would be interesting to find out what the actual firmware is in an IQ8 versus and IQ8 with Enphase backup.

The issue of Enphase doing something special to make their inverters AC couple when installed as part of their backup solution is an interesting one. The fact that they support a "Daylight Backup Mode" means the key "secret ingredient" is not the batteries. You need their System Controller for this. I don't have one of those but I know it serves as a central connection point for the inverters, the grid, the batteries, a generator, and the load. So maybe they have a dedicated "Grid Forming Inverter" in the controller or one specific "Grid Forming Inverter" is chosen from your PV array. I'm not sure if the controller box has a small battery in it. If it does it could continue to manage things and communicate even when there is no PV available.

If they actually install special firmware as part of the backup configuration that allows these PV inverters to work, that tends to indicate that their failure to operate when not part of a backup solution is deliberate. Never the less, it does appear that they are actually "Trying to fix this". They already have it working for IQ7s. As far as it working for Stacked Schneider Inverters, they are saying one inverter can handle PV that is 125% of the inverter rating or around 8500 watts. That should be enough for my array. If required in a prolonged outage, I could switch to a single inverter mode and just isolate the second inverter. I have some east and some west facing panels so I will never have all of my PV working at 100%. Still it will be close to the 8500 watts in the middle of summer, which is why I figured I needed two. I don't think I need two for consumption, unless I run my drier and my wall oven at the same time. Not something I would need in an outage.

 

[400bird]

Agreed but if I called Schneider sales today and asked them if the XW Pro can AC couple with Enphase what do you think they will tell me?

I'm pretty sure Schneider would say they support AC coupling with any capable (and under 6kw) grid tie inverter. The fact that one specific brand (Enphase) doesn't work with both SolArk and Schneider says to me that the Enphase equipment is doing something funky.

The issue of Enphase doing something special to make their inverters AC couple when installed as part of their backup solution is an interesting one.

Enphase uses power line communication to control their micro inverters.

To AC couple with a 3rd party inverter requires testing and verifying the local grid, just like wider grid from the power company.

 

[wheisenburg]

I'm pretty sure Schneider would say they support AC coupling with any capable (and under 6kw) grid tie inverter. The fact that one specific brand (Enphase) doesn't work with both SolArk and Schneider says to me that the Enphase equipment is doing something funky.


Enphase uses power line communication to control their micro inverters.

To AC couple with a 3rd party inverter requires testing and verifying the local grid, just like wider grid from the power company.

The fact that their older inverters seem to work just fine, and other brands of inverters also work seems to indicate that Enphase has an issue, deliberate or not. There is a spec for F/W curves that their inverters should be following when AC coupled to battery inverters. Simply shutting off and refusing to work does not comply with specs they say they have implemented.

 

[Hedges]

SMA systems have always used grid-forming SI with an SB in either "off-grid" or "backup" mode; in that case SB no longer performs anti-islanding.
With their latest -41 series SB, SMA's official documentation says to put it in "Rule 21" for grid backup.
But SMA America's videos have now said to use "backup" mode when SB -41 is behind SI. This suggests they too have some issues with even their own UL-1741-SA compliant GT PV inverters.

Those issues may be with anti-islanding. Although, I never had problems with that, just lack of gradual curtailment, using older UL-1741 SB. Another possible issue is curtailing to zero output, which might knock it offline for 5 minutes.

SMA also has HF (and HV) battery inverter SBS, which works with SB. In that case, it is possible Speedwire (Ethernet) is used to change settings. Haven't read comment of issues. But I suspect it sees fewer backup installations than does SI.

 

[solar8484]

I'm pretty sure Schneider would say they support AC coupling with any capable (and under 6kw) grid tie inverter.

That's my expectation as well and a problem. Anyone looking to decide on equipment purchase for a new system getting such info could easily make an expensive mistake (e.g. buying iQ8's vs iQ7's or SolarEdge). On the other hand, if Schneider (and other hybrid inverters) just published a list of compatible or incompatible grid-tied inverter models it could help prevent such mistakes and have more happy customers. Note, this does not mean hybrid inverter vendors need to go out and test every grid-tied inverter model. They can start with just using their customer support data.

 

[solar8484]

The issue of Enphase doing something special to make their inverters AC couple when installed as part of their backup solution is an interesting one. The fact that they support a "Daylight Backup Mode" means the key "secret ingredient" is not the batteries. You need their System Controller for this. I don't have one of those but I know it serves as a central connection point for the inverters, the grid, the batteries, a generator, and the load. So maybe they have a dedicated "Grid Forming Inverter" in the controller or one specific "Grid Forming Inverter" is chosen from your PV array. I'm not sure if the controller box has a small battery in it. If it does it could continue to manage things and communicate even when there is no PV available.

If they actually install special firmware as part of the backup configuration that allows these PV inverters to work, that tends to indicate that their failure to operate when not part of a backup solution is deliberate. Never the less, it does appear that they are actually "Trying to fix this". They already have it working for IQ7s. As far as it working for Stacked Schneider Inverters, they are saying one inverter can handle PV that is 125% of the inverter rating or around 8500 watts. That should be enough for my array. If required in a prolonged outage, I could switch to a single inverter mode and just isolate the second inverter. I have some east and some west facing panels so I will never have all of my PV working at 100%. Still it will be close to the 8500 watts in the middle of summer, which is why I figured I needed two. I don't think I need two for consumption, unless I run my drier and my wall oven at the same time. Not something I would need in an outage.

I feel bad for you. Keep us posted on how it goes.

 

[solar8484]

Simply shutting off and refusing to work does not comply with specs they say they have implemented.

The thing is that the iQ8 passed all required UL cert testing and works fine with the utility grid.

 

[Hedges]

On the other hand, if Schneider (and other hybrid inverters) just published a list of compatible or incompatible grid-tied inverter models it could help prevent such mistakes and have more happy customers. Note, this does not mean hybrid inverter vendors need to go out and test every grid-tied inverter model. They can start with just using their customer support data.

an N x M problem.
If the issue is grid-forming inverter impedance, maybe a standard for "gentle" anti-islanding could be defined, which battery and GT PV inverters could both be tested to.

Otherwise, it is on the installers. A big company could do more, but small ones to try a system and grow on what they learn from that customer.
Given the market penetration of Enphase, and possibly Sunny Boy & Fronius, a couple battery inverter manufacturers ought to test and guarantee operation with (some firmware revision) popular GT PV inverters.

I'm just sticking with pure SMA systems. And I've told them of one incompatibility (and older SB that didn't implement one of its documented modes.)

 

[solar8484]

If the issue is grid-forming inverter impedance, maybe a standard for "gentle" anti-islanding could be defined, which battery and GT PV inverters could both be tested to.

It would be best if there is a standard for a simple but safe way to disable anti-islanding (and any other grid disturbance injection) in grid-tied inverters for *intentional* islanding. Current standards only address unintentional islanding. I imagine it could be require a transfer switch meeting certain UL standards with an output to indicate disconnection from grid, that could serve as a qualified signal to grid-tied inverters to go into intentional islanding mode.

 

[wheisenburg]

I feel bad for you. Keep us posted on how it goes.

Well I have reliable power here. The few outages I have had tend to be of the 30 minutes to an hour. I would still like to get this working eventually, but it is not urgent.

 

[wheisenburg]

an N x M problem.
If the issue is grid-forming inverter impedance, maybe a standard for "gentle" anti-islanding could be defined, which battery and GT PV inverters could both be tested to.

Otherwise, it is on the installers. A big company could do more, but small ones to try a system and grow on what they learn from that customer.
Given the market penetration of Enphase, and possibly Sunny Boy & Fronius, a couple battery inverter manufacturers ought to test and guarantee operation with (some firmware revision) popular GT PV inverters.

I'm just sticking with pure SMA systems. And I've told them of one incompatibility (and older SB that didn't implement one of its documented modes.)

I have tried Grid Codes that are supposed to have the Anti-Islanding turned off. They still don't work. The Schneider inverters appear to be working correctly. There is a "High Resolution" data section in the Enphase monitor that shows the Frequency and Volts appear to be stable and within the limits. There are no messages from the inverters indicating that voltage or frequency are out of range. So it must be something else.

 

[Hedges]

Do like me and buy old-stock Sunny Boys. They are rock solid. At least the transformer-type 5000US series.

Playing with my TriPower, for which I need to use a step-up transformer, I was having issues with it disconnecting when seeing full 277V per phase. Backed off a bit with other turns ratios, I think it is working better. Haven't confirmed, may be voltage getting pushed higher.

Since Schneider has transformer output, may also behave that way backdriven. Can you set nominal line voltage a bit higher in the microinverters? Or buck the voltage they see down a bit with buck/boost transformer?

Easier, try dialing down voltage created by Schneider.

 

[GXMnow]

It appears to me that Enphase is using a very aggressive grid stability test. Even when the grid is up here, I se some of my cheaper LED lights flickering a bit when the Enphase iQ7's are producing decent power. And when I go off grid the flicker is much more noticeable. And when the iQ7's go offline, they were reporting "Grid Instability" in the log. Bu the voltage and frequency from the Schneider was solid and well within the correct range. My Fluke 76 meter showed 60.0 Hz and 121.8 volts on each leg, 243.4 from leg A to B at my backup loads panel. 5 of my iQ7's stay producing, always the same 5. The other 11 seem to take turns going offline. The production seems to just fall short of matching my load, so the battery is just slowly discharging, even in full sun. During the last real power failure, I tried messing around with turning the breakers in the Enphase combine off to reset the iQ7 inverters, but for some really odd reason, that caused the frequency to shift down to just 57.1 Hz. That locked out all of the Enphase inverters as a bad grid. To get it back, I had to shut down the XW which was supplying all of my power at the time. When it came back up, it was at 60.0 Hz again, and the same 5 iQ7's resumed producing after 5 minutes.

Enphase pushed a firmware update, and I can no longer change profiles or see the logs.

 

[solar8484]

It appears to me that Enphase is using a very aggressive grid stability test. Even when the grid is up here, I se some of my cheaper LED lights flickering a bit when the Enphase iQ7's are producing decent power. And when I go off grid the flicker is much more noticeable. And when the iQ7's go offline, they were reporting "Grid Instability" in the log. Bu the voltage and frequency from the Schneider was solid and well within the correct range. My Fluke 76 meter showed 60.0 Hz and 121.8 volts on each leg, 243.4 from leg A to B at my backup loads panel. 5 of my iQ7's stay producing, always the same 5. The other 11 seem to take turns going offline. The production seems to just fall short of matching my load, so the battery is just slowly discharging, even in full sun. During the last real power failure, I tried messing around with turning the breakers in the Enphase combine off to reset the iQ7 inverters, but for some really odd reason, that caused the frequency to shift down to just 57.1 Hz. That locked out all of the Enphase inverters as a bad grid. To get it back, I had to shut down the XW which was supplying all of my power at the time. When it came back up, it was at 60.0 Hz again, and the same 5 iQ7's resumed producing after 5 minutes.

You might want to check the firmware version on the micros. After the v04.28.xx firmware updates on the iQ7 it appears only profiles with anti-islanding disabled will work reliably when off grid.

Enphase pushed a firmware update, and I can no longer change profiles or see the logs.

You don't have access as the installer?

 

[GXMnow]

You don't have access as the installer?

Correct.
I had an installer password that got me into the Envoy and I was able to read the logs and set the profile, but after the firmware update where you need the token now, I can only view basic status. I can no longer see the logs or change the grid profile. When I try my installer password now, it give me an unauthorized error.

I guess I can either pay for the Enlighten Manager or take the proper courses on the Enphase web site to get it back.

 

[Hedges]

You're already being held hostage. Do you need updates? Can you use your system in perpetuity without them?

 

[GXMnow]

You're already being held hostage. Do you need updates? Can you use your system in perpetuity without them?

Enphase remotely handles updates, but the inverters are autonomous and will just keep making power with no data connection. They only thing I would lose if Enphase shut down would be the Enlighten cloud app that tracks the production. IT would be nice to have a local version of that so you don't need the internet to see what it's doing. It would be easy to be a power monitor on the entire array and see what the production is, but it would not give the data for each panel like I get through Enlighten.

 

[Hedges]

"I can no longer see the logs or change the grid profile."

You've lost the ability to configure them. Was that only available through the web, not something you could do locally?
Of course we also want to be able to read status.

My equipment, SI has a display and I can query and do at least some settings with membrane keypad.
The various SB and the TriPower (also SI) I access either via RS-485 or Ethernet.
I used to use Sunny Boy Control, a box with buttons and display, now use a PC.

There ought to be a way to talk to Enphase locally. It passes through Ethernet, so if not accessible, they are just denying you access.

The Wyze mesh routers I got, had to download app to iPhone to configure it. Later received a spam text from them. Haven't figured out to reset the app password that I've already lost. I think their configuration is local, and web was just to download, but don't know for sure.

 

[wheisenburg]

Do like me and buy old-stock Sunny Boys. They are rock solid. At least the transformer-type 5000US series.

Playing with my TriPower, for which I need to use a step-up transformer, I was having issues with it disconnecting when seeing full 277V per phase. Backed off a bit with other turns ratios, I think it is working better. Haven't confirmed, may be voltage getting pushed higher.

Since Schneider has transformer output, may also behave that way backdriven. Can you set nominal line voltage a bit higher in the microinverters? Or buck the voltage they see down a bit with buck/boost transformer?

Easier, try dialing down voltage created by Schneider.

Right now when running on grid my voltage at the controller runs 124-125. When off grid it run around 119. It doesn't seem like, over voltage is the issue. I have heard that Enphase is aware that they have an issue. They supposedly did a firmware fix in their IQ7s and are working on the IQ8s. If that's true it would seem a little pointless for me to waste too much time and money experimenting if the only thing that will really fix it is new firmware.

You need to use a special $500.00 configuration tool to adjust the voltage on the Schneider