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

solar8484 said:

You should be able to get Envoy local access token from the Enphase web site.

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Yes, I have the token, but the amount of accessible information has been reduced, relative to the past major version.

Gubman said:

Yes, I have the token, but the amount of accessible information has been reduced, relative to the past major version.

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I was a bit upset with Enphase when they did the update to my system. It took a bit of arguing, and I didn't get access back until they finally replaced my failing Envoy board. They basically had to give me installer access so I could configure the new board. Hopefully they don't block me back out now. They also gave me Enlighten Manager which gives you a ton of info.

Gubman said:

Yes, I have the token, but the amount of accessible information has been reduced, relative to the past major version.

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Yeah ... that's one thing I hate about Enphase. Owners don't have full access/control of the equipment they bought and own and can't disable updates that arbitrarily remove features/functions without warning.

All micro-inverter internal data plus PV production and Grid consumption data is collected in the IQ gateway aka Envoy and then transmitted into the Enphase cloud server. Enphase is in control of the system, it owns and controls the data, the end-user does not!

Enphase could easily develop a web-based end-user interface on the IQ gateway for accessing all data locally instead of forcing end-users to their cloud. Installers can access some of the data locally but not all as Gubman posted. And Enphase has a private and public API for accessing IQ gateway data programmatically. It's all about access control with an eye on potential future revenues for a toll on accessing data that the end-user should fully own in the first place. If ENPH continues to drop, Enphase might just do that: charge a monthly access fee to drive up revenue that they can't increase otherwise with their non-competitive battery backup solutions.

That's what I like about Schneider SE and Local/Home/Facility Insight. I can control and see all data locally with a web browser, I do not need to install an app, I am in control when and how to perform updates and cloud remote access is optional when needed but not required.

solar8484 said:

Yeah ... that's one thing I hate about Enphase. Owners don't have full access/control of the equipment they bought and own and can't disable updates that arbitrarily remove features/functions without warning.

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It is a downer, I agree. Tradeoffs abound when selecting solutions. We, the tinkerers, are most affected/vocal about such matters. Throughout the years, I've come to realize that we (as a group) are not the ideal target audience for them.

DER Solar said:

All micro-inverter internal data plus PV production and Grid consumption data is collected in the IQ gateway aka Envoy and then transmitted into the Enphase cloud server. Enphase is in control of the system, it owns and controls the data, the end-user does not!

Enphase could easily develop a web-based end-user interface on the IQ gateway for accessing all data locally instead of forcing end-users to their cloud. Installers can access some of the data locally but not all as Gubman posted. And Enphase has a private and public API for accessing IQ gateway data programmatically. It's all about access control with an eye on potential future revenues for a toll on accessing data that the end-user should fully own in the first place. If ENPH continues to drop, Enphase might just do that: charge a monthly access fee to drive up revenue that they can't increase otherwise with their non-competitive battery backup solutions.

That's what I like about Schneider SE and Local/Home/Facility Insight. I can control and see all data locally with a web browser, I do not need to install an app, I am in control when and how to perform updates and cloud remote access is optional when needed but not required.

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I'm in software, and yes, the above is not a technical challenge but an (upper) management one at we know where...

Hoymiles inverters (HMS-700-2T) AC-couple flawlessly with Schneider XW-Pro inverters. Have a small 7 x 250W-panel off-grid system for the initial testing. Will expand it to 4.5 kW over the weekend and perform more in-depth testing.

Finding lots of interesting details and differences between Hoymiles and Enphase micro-inverters.

IQ8+ AC coupling: Why it doesn't work with FW!
IQ8+ inverters are very slow to respond to FW power curtailment by the XW-Pro frequency shift. They shut of permanently when frequency gets too high.

Test A: 1 IQ8+, PV connected to 50A AGM battery, 300W AC backfeed into an idle XW-Pro 6848
FW linked to SOC at 98%.
When the XW-Pro SOC reaches 98%, it raises the frequency to 63.5 Hz within 2 seconds. IQ8+ shuts down and never comes online again.
Enphase support needs to reset/reboot the inverter, that's how they know you have an non-Enphase AC coupled system. The reset/reboot feature is not available in the installers toolkit. You can also disconnect the PV input which will clear out the FW history in the inverter and then the IQ8 starts normally with the 5 minute wait.

Test B: 1 IQ8+, PV connected to 50A AGM battery, 300W AC backfeed into an idle XW-Pro 6848, 100W resistive load, 200W battery charging
FW linked to SOC at 98%.
When the XW-Pro SOC reaches 98%, it raises the frequency only to 62.5 Hz within 2 seconds because of the lower inrush current. IQ8+ shuts down and comes online after the frequency returns to 60 Hz and the additional 5 minutes.
This cycle can be repeated reliably.

Test C: 1 IQ7+, PV connected to 50A AGM battery, 300W AC backfeed into an idle XW-Pro 6848.
FW linked to SOC at 98%.
When the XW-Pro SOC reaches 98%, it raises the frequency to 60.5 Hz and the IQ7+ shuts down. IQ7+ comes online after the frequency returns to 60 Hz and the additional 5 minutes.
This cycle can be repeated reliably.

IQ7's respond better and faster to FW frequency shift.

IQ8's shut off permanently when the frequency shift approached 63.5 Hz, but come back online when the frequency stays below 62.5 Hz.

Hoymiles:
For comparison, the XW-Pro raised the frequency to 66Hz with 1250 W input from Hoymiles inverters, but they accepted the shift and returned to normal operations at 60 Hz plus the 5 minutes wait.

66 hz! And you think that's better?
That's way outside of any spec I've ever seen.
I'm pretty sure the 60hz +/- 2.5 that the Enphase reacted to is the proper operation.
And, yes repeating the cycle over and over again as the frequency changes is to be expected.

What grid profile did you have in the Enphase inverters? I'm pretty sure there are some grid profiles that require PV output to taper not just cut off entirely.

I'm curious about the grid profile and other experiment setup as well. A couple of the numbers and setup don't make sense.

FW linked to SOC at 98%.

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How were the battery charge settings chosen? Can you tell the XW to have maximum shift of 63 and use relay disconnect above that?

Why did FW start at 98%? Is it because of the low battery charge current? Did you try with 90% which is the recommended setting for XW? Does XW use the grid code F-W settings to determine the shift range? (I'm going off this document https://www.solar-electric.com/lib/wind-sun/Conext-XW-Pro-SW-AC-Coupling-Guide.pdf)




I think you should test again with the Hoymiles capped to the same wattage limit as your IQ8+. You can throttle their output by % so just set 43%.

I don't believe 66HZ is allowed, so something is wrong with the Hoymiles profile. Or, do you mean that Hoymiles cut way down to 0% already by 62.5HZ? That would be fine.

400bird said:

66 hz! And you think that's better?
That's way outside of any spec I've ever seen.

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I did not think or say that this would be better, it is just an observation what the XW-Pro does off-grid. And it is perfectly ok to raise the frequency to get the micro-inverter to stop producing.

There is a major difference for an XW or similar ESS inverter to be grid-tied and required to be a grid follower versus being a micro-grid driver.
Grid connection rules should be same for grid-connected ESS inverters and grid connected micro-inverters and are tested by the underwriter for compliance. It is not ok to change the grid profiles in either the XW-Pro or the micro-inverter to make AC coupling off-grid work.

What an ESS inverter does off-grid is not regulated and the grid-tied rules do not apply. Performing power curtailment in an off-grid scenario outside the required grid-tied grid-profile is ok and up to the designer of the off-grid inverter behavior.

I have suggested to inverter manufacturers to support 2 grid profiles: a grid-tied fixed one that cannot be changed and is compliant for the US region plus a 2nd one for off-grid use that can be fully configured to work in diverse retrofit AC coupling applications.

Will respond to your specific questions later.

To the best of my knowledge, no one on this forum has successfully AC coupled IQ8+ inverters with FW or similar power curtailment.
IQ8's can be AC coupled with a hard on/off PV relay. This what Franklin WH, EP Cube, Qcells QHOME, Sol-Ark using the generator port, and many others do to get it to work.
Several DIY users have reported that the IQ8 inverters shut down and stay shut off, requiring a reboot by Enphase.

I have been trying to find out why they would not come back online.

DER Solar said:

IQ8's can be AC coupled with a hard on/off PV relay. This what ... Sol-Ark using the generator port ... do to get it to work.

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Has IQ8 with Sol-Ark been done successfully?
I've read here of people trying, maybe a couple connect but not the entire Enphase IQ8 PV array. It seemed the anti-islanding caused it to disconnect.

If it works like basic UL-1741, connect at full wattage and disconnect when frequency is raised, that would be good enough for a DC PV + AC coupled PV system like SolArk recommends.

Hedges said:

Has IQ8 with Sol-Ark been done successfully?
I've read here of people trying, maybe a couple connect but not the entire Enphase IQ8 PV array. It seemed the anti-islanding caused it to disconnect.

If it works like basic UL-1741, connect at full wattage and disconnect when frequency is raised, that would be good enough for a DC PV + AC coupled PV system like SolArk recommends.

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I don't know any successful IQ8 AC coupling with FW power curtailment. IQ 8's can be AC coupled with FW off, constant 60 Hz, and using the generator relay for PV on/off. But then you loose the generator port for additional gas powered backup. I know an installer in Canada who got IQ8's to work with Sol-Ark on the generator port.

Looks like IQ8's may work off-grid if the ESS inverter does not raise the frequency above 62 Hz.

I thought people had trouble just getting IQ8 to connect and remain connected at 60 Hz. I thought it was the anti-islanding.
If they do connect reliably and only disconnect with frequency shift, that is at least usable.
People also say more issues for HF inverters, when those have to change from inverting to battery charging.

I think testing needs to be done with multiple IQ8 at once (typical size deployment like say mandated minimum solar size for California building code), they might use an anti islanding whose behavior depends on the number of microinverters

DER Solar said:

I did not think or say that this would be better, it is just an observation what the XW-Pro does off-grid. And it is perfectly ok to raise the frequency to get the micro-inverter to stop producing.

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I think you miss understood me. The XW is doing anything it can to try and stop the micro inverter. My question was about why the Holymiles just kept going, way past any frequency threshold I've seen, 66hz is quite high. Look at the California Rule 21 spec Zanydroid posted above (post #209) the inverters are required to stop at 62hz.

DER Solar said:

It is not ok to change the grid profiles in either the XW-Pro or the micro-inverter to make AC coupling off-grid work.

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I was not suggesting you change profiles to make it work ?
Just asking if you had some odd profile selected on the Holymiles. However, after saying this, you follow it up by suggesting the exact opposite, you want two profiles and to switch between them to make off-grid work:

DER Solar said:

I have suggested to inverter manufacturers to support 2 grid profiles: a grid-tied fixed one that cannot be changed and is compliant for the US region plus a 2nd one for off-grid use that can be fully configured to work in diverse retrofit AC coupling applications.

Click to expand...

400bird said:

I think you miss understood me. The XW is doing anything it can to try and stop the micro inverter. My question was about why the Holymiles just kept going, way past any frequency threshold I've seen, 66hz is quite high. Look at the California Rule 21 spec Zanydroid posted above (post #209) the inverters are required to stop at 62hz.

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Maybe response time of Hoymiles?

Try reducing ramp rate of XW. (Which means it has to stuff more Wh into batteries.)

DER Solar said:

Hoymiles inverters (HMS-700-2T) AC-couple flawlessly with Schneider XW-Pro inverters. Have a small 7 x 250W-panel off-grid system for the initial testing. Will expand it to 4.5 kW over the weekend and perform more in-depth testing.

Click to expand...

The results would be more useful if you specify the grid profiles used on the iQ8's. Grid profiles (e.g. CA Rule 21) that support proportional FW curtailment should be used for the tests.

Also, testing 1 iQ8 against Schneider likely won't represent realistic behavior due to the vast power capacity differences. I have seen several reports of a few iQ8's working reliably against Schneider but not when the iQ8 power capacity gets closer (even 1/3) to that of the Schneider.

EG4 has document on testing they did with IQ8 and the 18kpv: https://eg4electronics.com/backend/...3/04/EG4-18kPV-AC-Couple-with-Enphase-IQ8.pdf

From the EG4 doc/video, it's unclear if they have iQ8 AC coupling working off grid. Most grid-interactive hybrid inverters have no issue AC coupling with iQ8's when on grid.