Sol-Ark 12K + Enphase IQ8 microinverters

[kennyb]

The behavior is very odd running off grid with this profile initially I'll see full PV power generation of 7 or 8 or 9 kilowatt hours and then it gradually decreases to one or two kilowatts and then it shuts itself off when that AC frequency from the Sol-arc shifts

The IEEE 2015 shuts down at 60.5hz. So this is why you see the quick curtailment and shutoff.
It's very odd though that with your soc&voltage so low the solark is raising your frequency.


your findings are inline with that solark told me recently "only when the batteries reach a low state of charge the Sol-Ark will call for the AC coupled system to charge the batteries (during day time) and power the loads until the batteries reach a full SOC. Once the batteries are fully charged, the Sol-Ark will turn off the AC-coupled system and continue using DC PV and batteries. "


If you ask me, Ac couple should be able to regulate via frequency curtailment and only use the relay as a means of a redundant backup for charge controlling. It seems that the GEN port uses the relay as the primary means of charge control.

 

[solar8484]

I doubt the small frequency shift observed is due to SolArk doing freq-watt control unless SolArk provides clear indication that actual freq-watt control was active. More likely it's due to iQ7's anti-islanding mechanisms which include frequency shifted disturbance injections. For iQ7's (not iQ8's) with recent firmware versions the only fix appears to work reliably is to use a grid profile with anti-islanding disabled. SolArk gen input relay is really not a great fix for the problem. It could lead to early failure if the relay is frequently cycled on and off as AC coupling sync attempts repeat. Also, little AC coupling energy will be realized this way. Given the problem reports in this forum and the lack of robust resolution from SolArk support, it appears SolArk is not suitable for off-grid AC coupling with Enphase iQ series.

People looking at buying hybrid inverters for AC coupling should ask the vendors up front if they have specifically tested with the target grid-tie inverters.

 

[Techy D]

I doubt the small frequency shift observed is due to SolArk doing freq-watt control unless SolArk provides clear indication of actual freq-watt control was active. More likely it's due to eh iQ7's anti-islanding mechanisms which include frequency shifted disturbance injections. For iQ7's (not iQ8's) with recent firmware versions the only fix appears to work reliably is to use a grid profile with anti-islanding disabled. SolArk gen input relay is really not a great fix for the problem. It could lead to early failure if the relay is frequently cycled on and off as AC coupling sync attempts repeat. Also, little AC coupling energy will be realized this way. Given the problem reports in this forum and the lack of robust resolution from SolArk support, it appears SolArk is not suitable for off-grid AC coupling with Enphase iQ series.

People looking at buying hybrid inverters for AC coupling should ask the vendors up front if they have specifically tested with the target grid-tie inverters.

Agreed. I would not recommend AC coupling IQ series micros with Sol-Ark if you plan to use the AC coupled solar frequently off grid.

It works for my situation because 98% of the time the system is on grid and due to where I live the chances of a power outage during peak summer time is few and far between... that being said, I still wanted to make sure that the micros would work in a grid down situation just to top up the batteries.

 

[solar8484]

that being said, I still wanted to make sure that the micros would work in a grid down situation just to top up the batteries.

Of course, otherwise your big investment in grid-tied PV system is completely useless in blackouts when you need it to provide power the most. Spending more money on DC coupled PV or batteries is just an expensive workaround.

 

[12kw_2021]

Good afternoon

I think I have a reasonable solution to operate with AC coupled PV off grid.

I spent > 1 hour on the phone with Enphase Tech support this afternoon.

They watched my system go from >9KWh to 300w several times while my main grid feed was disconnected for my experiment.

They indicated that they did not see any V or HZ (frequency issues) that causes the PV to drop off.

I am not sure I believe that because in my installer software I can see that when the Sol-ark is running with AC grid pin PV the frequency does indeed move around and it does appear to cause the Enphase micro inverters to turn off.

So the gentleman who commented above that going from 60HZ to 60.5 or higher causes the Enphase to turn off appears to be correct.

Enphase indicates that the inverters are "very sensitive" to changes in frequency. See image capture from my installer program looking carefully at todays test .

Good news: Enphase Grid Profile: Off-Grid FW60 No Export works with Sol-ark off grid

Enphase installed this grid profile today, during my 'off grid' experiment, where I flipped my grid connect switch off for testing off grid operation on a a very sunny > 9kw day.

Steps needed to run Sol-ark AC coupled Enphase Iq7a off grid on good PV day.

1.0 Update the grid profile to Grid Profile: Off-Grid FW60 No Export
2.0 Reboot your combiner box by turning off the 15A circuit breaker for 30 second, then turn it back on. This causes the Enphase to re-connect/reset and query all attached micro inverters and restart the PV production.
2.1 If you skip this , and just change the grid profile it doesn't work.
3.0 In my case the available PV was 9kw and on restart it started running with around 6-7kw.
4.0 Battery is recharged and 100% of home loads are fully supported using PV.
5.0 You can use the enphase "live view" and watch it go up when you turn on your oven or a heat pump, when the load goes down the PV sent to the Sol-ark also decreases (See images attached).
6.0 This operation does not attempt to export power (IE zero export), and gracefully ramps the PV up or down to support load.
7.0 It does not appear to fully utilize the available PV, so even tho I have >9kw of PV available it gradually ramped down from 6KW of production , then stabilized around 3kw with 2.5kw going to the battery re-charge, and 500kw supporting the home loads.

So I now have a path forward if/when an extended grid outage occurs.
I will continue my investigation of other grid profiles to see if I can find one that I can set and forget, but as of now, just confirming that a grid profile update to my enphase micro inverters allows usage of available PV and battery charge is fine with me.

See images from Enphase and Sol-ark attached.

Regards hope this information helps someone else who is looking for an improve AC couple Sol-Ark Enphase solution . It is possible.

 

[solar8484]

The Off-Grid FW60 grid profile is one of the ones with anti-islanding disabled and that's why things are working for you now.

 

[12kw_2021]

The IEEE 2015 shuts down at 60.5hz. So this is why you see the quick curtailment and shutoff.
It's very odd though that with your soc&voltage so low the solark is raising your frequency.


your findings are inline with that solark told me recently "only when the batteries reach a low state of charge the Sol-Ark will call for the AC coupled system to charge the batteries (during day time) and power the loads until the batteries reach a full SOC. Once the batteries are fully charged, the Sol-Ark will turn off the AC-coupled system and continue using DC PV and batteries. "


If you ask me, Ac couple should be able to regulate via frequency curtailment and only use the relay as a means of a redundant backup for charge controlling. It seems that the GEN port uses the relay as the primary means of charge control.

I agree, and have data from my enphase installer app that shows the AC frequency is moving around and does indeed appear to cause the micro inverters to go off line if it goes > 60.5 Hz see attached

 

[12kw_2021]

The Off-Grid FW60 grid profile is one of the ones with anti-islanding disabled and that's why things are working for you now.

Ok, interesting, not sure how you know this, but thank you very much..

The "tech support" at enphase wasn't the best, but they did suggest and install this grid profile.

Is there any risk of flipping my connection back to the grid, and leaving this grid profile installed?My guess is the Sol-ark will take care of things, and the AC coupled PV is directly connected to the Sol-ark.. and it wastes a lot of available PV I can now export, so my plan is to only use this grid profile if/when an extended grid down situation occurs.

Since you know this level of detail are there any grid export grid profiles that have a larger tolerance for variations in the supplied AC that I could set and forget?

So far I have not found any grid profile with export allowed that will continue to run when I manually disconnect from the grid. And this made me cranky about having all that shiny stuff in my backyard that was worthless in a grid down situation.

So for now I have a "grid profile change" when grid down solution.

Thanks again for sharing.

 

[solar8484]

Ok, interesting, not sure how you know this, but thank you very much..

A lot of testing. Some profiles have description or name that tell you anti-islanding is disabled. But to know for sure you have to use an oscilloscope to check the voltage and current waveforms. When Enphase iQ7 anti-islanding is active in an island created by a grid forming inverter like SolArk you can see some nasty looking waveforms. The iQ7 anti-islanding is too aggressive even for some utility grids as there are many reports of periodic PV dropouts that I have observed as well. Most people don't notice because they are relatively short and Enlighten monitoring generally don't show them.

The "tech support" at enphase wasn't the best, but they did suggest and install this grid profile.

You should ask them directly to give you a list of all grid profiles with anti-islanding disabled.

Is there any risk of flipping my connection back to the grid, and leaving this grid profile installed?My guess is the Sol-ark will take care of things, and the AC coupled PV is directly connected to the Sol-ark.. and it wastes a lot of available PV I can now export, so my plan is to only use this grid profile if/when an extended grid down situation occurs.

I don't see any significant risk. Your Enphase micros are behind the SolArk.

Since you know this level of detail are there any grid export grid profiles that have a larger tolerance for variations in the supplied AC that I could set and forget?

So far I have not found any grid profile with export allowed that will continue to run when I manually disconnect from the grid. And this made me cranky about having all that shiny stuff in my backyard that was worthless in a grid down situation.

Try "IEEE 1547 Default 2015 FW200 no-AI".

So for now I have a "grid profile change" when grid down solution.

Thanks again for sharing.

Good luck.

 

[12kw_2021]

A lot of testing. Some profiles have description or name that tell you anti-islanding is disabled. But to know for sure you have to use an oscilloscope to check the voltage and current waveforms. When Enphase iQ7 anti-islanding is active in an island created by a grid forming inverter like SolArk you can see some nasty looking waveforms. The iQ7 anti-islanding is too aggressive even for some utility grids as there are many reports of periodic PV dropouts that I have observed as well. Most people don't notice because they are relatively short and Enlighten monitoring generally don't show them.


You should ask them directly to give you a list of all grid profiles with anti-islanding disabled.


I don't see any significant risk. Your Enphase micros are behind the SolArk.


Try "IEEE 1547 Default 2015 FW200 no-AI".


Good luck.

Thanks again for the inputs, will let you know what I learn, but with my 32 EVE 280Ah cells, I have now demonstrated that I can run my entire home for 24 hours off grid on days when there is good PV available, and this off grid profile.

My experience on grid using my battery overnight, I only use 1-3kWh from the grid each day, and export 20-60 kWh so I am building up a big bank of stored power to use in winter when the weather around here is not at all PV friendly.

The 1-3kWh is just the constant 60w of power I have programmed into the Sol-ark to pull from the grid, and even tho the screen says you can set this at zero , they don't recommend doing that for reasons I don't fully understand.

I also fully agree with your feedback that the Iq7xx micro inverters are "very demanding" of a near perfect grid input and that minor transients from the Sol-ark can and do kick them off grid.

It's frustrating to me that when this happens "live" with an Enphase Tech support connected remotely to my system they just mumble when it goes down, and say you need to change your grid profile, and don't give a specific data point worthy answer I can share with Sol-ark. IE.. V went high/low, Freq, went high/low but if the transient is fast enough , I also understand that they may not even be able to see it.

My goal is to get Sol-ark to update the manual with improved "How to run our Inverter with AC coupled PV only" instructions, but I realize that I am an odd duck, and most folks just connect DC PV to the Sol-ark, and are happy and it works on or off grid.

Sorry for such long winded reply, and thanks again for sharing.

 

[wheisenburg]

Data from the enphase installer application shows that the solark AC Gen pins frequency shifts as high as 60.6 hz and this causes the iq7a to turn off.

This would seem to be an SolArk issue. It is clearly frequency shifting the micros to the point that they turn off. The problem seems to be that it is doing this despite a low battery SOC. What does Sol Ark say about this? On my Schneider, I was able to observe my inverters ramp up (using the IEEE 2015 default) and then the Schneider sent a 1-2 second pulse of 62 HV and shut the inverters down. That is not unexpected. I was running at a high SOC at the time.

I plan on doing some more testing soon to see exactly how well (or how poorly) the Schneider can manage the PV output and SOC using AC coupling. I'm going to try going off grid today with only one of my inverter strings hooked up and see how well things perform.

When I have switched the Schneider over to manage the battery using SOC, it actually did not perform reliably. I am not sure it is a battery issue or the Schneider. Right now I trigger a recharge cycle when the battery hit 53.1 volts. This tops the battery off about every three days. I think the Schneider may draw it's idle current from the battery not the AC. It seems to draw around 30 watts from the batteries at idle. Either that or each battery consumes 10 watts, which I suppose is possible too.

 

[wheisenburg]

Try "IEEE 1547 Default 2015 FW200 no-AI".

The FW200 part of this profile says lower the output by 200% for each 1% increase in frequency. In other words full curtailment of PV will occur at 60.5 HZ. Now that may not be an issue if it is the AI that is causing the inverters to turn off. There are comments on this profile that it only works on IQ7 inverters. I did not notice this and installed it on my IQ8s. They would not turn on at all. I switched back to another profile, and my inverters never came back even when on grid. I had to call tech support and they did something to reset them.

So far at least on my Schneiders I have been able to get things to run with the standard IEEE 1547 profile, but they shut off when Schneider sent them a 1-2 second 62 HZ pulse. That is expected. I was at a high SOC. I didn't leave things on to see what would happen next. I am going to do some more testing soon. Maybe Monday.

 

[Hedges]

Rule 21: From 60.5 Hz to 62 Hz, mandatory ride-through for 299 seconds.
That should tolerate brief excursions above 60.5 Hz. Frequency exceeding 62 Hz would cause disconnect.

Would like GT PV inverter to do frequency-watts so briefly above 60.5 Hz ceases output, no need for SolArk to reach 62 Hz and cause disconnect. SolArk could then gradually reduce frequency until GT PV delivers desired wattage.

My Sunny Islands don't jump up in frequency, rather ramp up and down in a few seconds, so they have to absorb the power during that time. I'm using AGM not lithium, so no issue with voltage running too high; they may want reduced SoC to absorb it.

California’s Interconnection Rule 21: What it means for utilities and customers across the US

California´s new interconnection rule 21 is redefining the role of distributed energy resources (DERs) in the modern electricity network.

www.openintl.com

 

[solar8484]

Thanks again for the inputs, will let you know what I learn, but with my 32 EVE 280Ah cells, I have now demonstrated that I can run my entire home for 24 hours off grid on days when there is good PV available, and this off grid profile.

Good to hear it's working. With that battery bank size you can probably stretch it to last a few days if necessary.

My goal is to get Sol-ark to update the manual with improved "How to run our Inverter with AC coupled PV only" instructions, but I realize that I am an odd duck, and most folks just connect DC PV to the Sol-ark, and are happy and it works on or off grid.

I am still doubtful that Sol-Ark does any meaningful testing with the popular grid-tied inverters (e.g. Enphase and SolarEdge) in the US.

 

[solar8484]

The FW200 part of this profile says lower the output by 200% for each 1% increase in frequency. In other words full curtailment of PV will occur at 60.5 HZ. Now that may not be an issue if it is the AI that is causing the inverters to turn off. There are comments on this profile that it only works on IQ7 inverters.

That's correct. The fast FW ramp rate helps with slow reacting grid forming inverters.

I did not notice this and installed it on my IQ8s. They would not turn on at all. I switched back to another profile, and my inverters never came back even when on grid. I had to call tech support and they did something to reset them.

Based on your previous reports that's not really surprising at all. These profiles were created before iQ8 existed so it's pretty certain that these profiles don't have the necessary settings for iQ8's grid forming functionality. You need Enphase to update/create profiles to add the settings to disable all grid forming functions in the iQ8. I can imagine the current profiles have a setting that tells the Enphase micros to "go off-grid" which can have totally different meaning in iQ8 compared to iQ7. In iQ8 "go off-grid" could mean start grid forming which would only lead to nothing good.

So far at least on my Schneiders I have been able to get things to run with the standard IEEE 1547 profile, but they shut off when Schneider sent them a 1-2 second 62 HZ pulse. That is expected. I was at a high SOC. I did leave things on to see what would happen next. I am going to do some more testing soon. Maybe Monday.

One thing that can be misleading is that anti-islanding often cause observed frequency shift. So, unless you have data (e.g. event log) that clearly indicates your Schneider is doing frequency shift then it's more likely the frequency shift is due to anti-islanding especially when your battery is nowhere near full.

 

[DER Solar]

There is a recurring theme in all the AC coupling feedback reported on this forum: anti-islanding by measuring grid impedance.
50 KVA utility transformers have a very low impedance, transformer-based inverters like XW have medium impedance with the 60 Hz toroidal transformers at 6.8 KVA, Enphase has a 3.6 KVA NFT transformer, Victron offers a 100A 24KVA auto-transformer, and TL inverters like SolArc or LuxPower 12k have a high impedance, in some installations an auto-transformer is added to raise imbalanced loads.

It is interesting that IQ7's and IQ8's with anti-islanding enabled start shutting off at different frequencies in different AC coupled setups.
They also shut off when the load (that's added impedance) on the micro-grid changes, especially when the load is shut off.

While Enphase supports different grid profiles, they can also change the implementation of the profile internals at will and keep the name of the profile the same.

As Hedges has shown in CA Rule 21, the inverter should stay on/ramp down up to 62 Hz, but IQ7's and IQ8's shut off much faster around 61 Hz.
Per CA rule 21, they should perform exactly as specified when connected to the low-impedance utility grid, and they do otherwise they would not pass UL 1741 SA certification.

How these inverters behave in a micro-grid is totally up to Enphase! Enphase could change the inverter response by measuring grid impedance.
POCO utility rules do not apply to micro-grids!

When I tested a Hoymiles HMS-2000 UL 1741 SB quad inverter with XW Pro in backup mode, it responded exactly as required by CA Rule 21 and ramped down production linearly with the frequency shifting from 60 Hz to 62 Hz, shutting off at 62 Hz.

There is one test I would like to perform: add additional auto-transformers to raise micro-grid impedance. I have 2 spare XW toroidal transformers plus a 5KVA autotransformer. Would be interesting to know at what micro-grid impedance the IQ8's perform more like CA Rule 21 on a utility grid.

Of course, the best solution would be for Enphase to support AC coupling with a UL 1741 SA/SB profile and less aggressive anti-islanding or anti-islanding disabled, Hoymiles testing has shown that this is possible to have anti-islanding enabled. But any successful AC coupling of Enphase inverters with non-Enphase backup systems will have an impact on ENPH's growing (or stalling) bottom line for selling backup solutions. It's about time Enphase get's serious competition from other micro-inverters that can be AC coupled to non-Enphase backup systems.

 

[Ampster]

Is there any risk of flipping my connection back to the grid, and leaving this grid profile installed?

I agree with @solar8484 and my understanding is that there is no risk because the SolArk will provide the anti islanding. The micros have to flow through the SolArk so when the SolArk disconnects from the grid the micros are disconnected.

 

[Ampster]

My goal is to get Sol-ark to update the manual with improved "How to run our Inverter with AC coupled PV only" instructions, but I realize that I am an odd duck,

I agree, and would like to see this happen as well. I have added 2kW of DC coupled solar and will probably add another kW so I can limp through a power outage without AC coupling. However I still would like to find a solution in case we have an extended outage during cloudy weather and I need the additional generation that my 6.6kW of IQ7s could provide.

 

[12kw_2021]

This would seem to be an SolArk issue. It is clearly frequency shifting the micros to the point that they turn off. The problem seems to be that it is doing this despite a low battery SOC. What does Sol Ark say about this? On my Schneider, I was able to observe my inverters ramp up (using the IEEE 2015 default) and then the Schneider sent a 1-2 second pulse of 62 HV and shut the inverters down. That is not unexpected. I was running at a high SOC at the time.

I plan on doing some more testing soon to see exactly how well (or how poorly) the Schneider can manage the PV output and SOC using AC coupling. I'm going to try going off grid today with only one of my inverter strings hooked up and see how well things perform.

When I have switched the Schneider over to manage the battery using SOC, it actually did not perform reliably. I am not sure it is a battery issue or the Schneider. Right now I trigger a recharge cycle when the battery hit 53.1 volts. This tops the battery off about every three days. I think the Schneider may draw it's idle current from the battery not the AC. It seems to draw around 30 watts from the batteries at idle. Either that or each battery consumes 10 watts, which I suppose is possible too.

Hello
I have not yet shared the enphase data showing that the Sol-ark frequency is shifting up, and causing the IQ7a inverters to turn off.

I am sharing my attempts to run "off grid" with only AC coupled PV (12Kw) and 30Kwh or battery storage. I will share updates as I learn more.

I am going to push Enphase to share additional grid profiles to test using my setup, and make a request in writing to share any grid profiles that are more "forgiving" IE allow the IQ7A's to continue operating if/when the grid frequency shifts from 60 to 61 Hz, and see what they have.

They have mentioned that they have locations (Hawaii, Puerto Rico, others) with grids that are unstable, and I can image that there may be some folks who live in the boonies that have grid power available, but it is less than ideal, and Enphase would need to have a solution to keep the PV running in those situations.

Wish me luck

 

[12kw_2021]

I agree, and would like to see this happen as well. I have added 2kW of DC coupled solar and will probably add another kW so I can limp through a power outage without AC coupling. However I still would like to find a solution in case we have an extended outage during cloudy weather and I need the additional generation that my 6.6kW of IQ7s could provide.

Ampster.. just to be clear , with the current "Off-Grid FW60 No Export" grid profile installed, and my 12Kw PV AC coupled only input, I have been charging batteries, and supporting loads for > 24 hours.

My 30kWh battery bank was charged to around 93% when the sun went down last evening, and everything stayed up overnight, and when PV was available I am recharging the battery and supporting all loads, and when a new load shows up the PV supplied jumps up to support same, so this grid profile appears to meet the need for an extended off grid issue.

Current problem is when I look in the installer tool kit, I don't see this grid profile available, and my second concern is if/when the grid goes down if the internet goes down as well, how do I modify the grid profile to the needed one?

I am satisfied that I have a solution for a grid down, with a100% IQ7a enphase system AC coupled to the Sol-ark , and the Sol-ark disables the PV when my battery hits 95% SOC, and then turns the PV back on when it drops below 65% which are my "smart load" settings.

I have also considered adding some DC panels to the Sol-ark, but would like to get as much value as possible out of my current investment.

Do other folks have access to this Off-Grid FW60 No Export grid profile, and I am just not looking in the correct place on the enphase installer www site?

Will continue to update here results, Ideal situation would be to identify a "set and forget" grid profile that will operate with Grid up, or Down and the Sol-ark 15kw, we shall see if that grid profile exists, or if perhaps Sol-ark could convince Enphase to develop one.

I was going to remove the current grid profile and go back to grid export mode, but since I do not see the current grid profile available, I am just going extend my off grid test and build up more information to share and learn, as long as the sunny weather continues, and I have no wife problems with a "oops honey, sorry we have no power cause I was screwing around with the system."



I have attached some Sol-ark Freq vs time, Iq7a PV power vs time, and battery SOC vs time. It does appear that the Sol-ark shifted the freq up to 62hz when the 94% battery SOC was reached, and this caused the PV generated to drop. Not sure I understand why it did not stay off, longer, but at least it appears that the Sol-ark can be "in charge" and my BMS doesn't need to trip
Still learning