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

I've played with VFD (feeding a HyPot), wasn't using a scope, but I doubt waveform looks good to a GT PV inverter.

Not sure if Sunny Island can be commanded to new frequency on the fly. Could configure a Sunny Boy to do frequency-watts ramp from 60 Hz to 64 Hz, then vary load to make frequency shift occur for IQ8 to see.
 
DER Solar said:
Too complicated, why detect the change in frequency if the XW-Pro has a trigger capability on battery high voltage, including hysteresis. What it does not support is something similar for closed loop SOC. There is no hysteresis on SOC anywhere. Disable FW and keep f = 60 Hz constant.
Click to expand...
Not sure what you're proposing. Trigger a relay that disconnects when the voltage or SoC is at a level where XW can't absorb the excess power from microinverters? Does that approach work? If so, what is the advantage of FW vs this approach?

The idea with the frequency-triggered relay is to attempt to still use FW most of the time (and maybe get intermediate control), and then disconnect the microinverter if the grid forming microinverter misbehaves.

What is raising the frequency, the IQ8 or the XW? IQ8 use Group 1 anti-islanding:
1700191734106.png

Does the XW know that it is the boss quickly enough after grid disconnect and shouldn't participate in Group 1 (if that is the method it uses).

Finally figured out what Droop Slope means (from a NREL paper). If possible to customize the XW grid profile maybe set a sharper than usual droop slope. Something like 5% is the default in 1547 2018 if I google. That gets up to 63Hz which is dangerously close to pissing off the Enphase.

1700191183201.png
 
Sunny Island: That would be a great test, having an inverter where the FW shift up ramp can be specified, especially the end point and a ramp slope or gradient over time.
 
zanydroid said:
Not sure what you're proposing. Trigger a relay that disconnects when the voltage or SoC is at a level where XW can't absorb the excess power from microinverters? Does that approach work? If so, what is the advantage of FW vs this approach?

The idea with the frequency-triggered relay is to attempt to still use FW most of the time (and maybe get intermediate control), and then disconnect the microinverter if the grid forming microinverter misbehaves.
Click to expand...
Exactly! The XW-Pro has a built-in auxiliary output port that can be triggered by a battery voltage at a defined level. This is exactly the approach that works in Franklin WH, EP Cube and other inverters. When Sol-Ark AC generator is tied to SOC, the relay will open and disconnect the PV array.

The idea of FW is a graduated approach to power curtailment. PoCo's can raise the grid frequency to 60.2 Hz and see if they get a reduction in PV power generation, then they raise it a little bit more. But this is not the way most ESS inverters work. The ones I know do not have a FW function over SOC and over time.

As my IQ8 test has shown, all it takes is a 300W imbalance between production and consumption to disable an IQ8. Real PV production and real loads have much higher imbalances.
 
DER Solar said:
The idea of FW is a graduated approach to power curtailment. PoCo's can raise the grid frequency to 60.2 Hz and see if they get a reduction in PV power generation, then they raise it a little bit more. But this is not the way most ESS inverters work. The ones I know do not have a FW function over SOC and over time.
Click to expand...

I'm not sure the FW intermediate power states are all that useful for rapid response when the mandatory response speed is something like 5s (saw it yesterday when reading the documentation).

However it is likely very useful as a graceful way to go to 0W, without having to risk forcing the microinverter off through a path that it might not come back from, or has a tiny chance of damage.

It could also be very useful for slower responding goals. For instance, if you have too much AC size for the charger/inverter/battery rating and want to cut it down to 50% to stay within design rules. And in the morning, it could be set to 100% b/c there isn't that much sun, going down to say 50% by mid day when there's too much. Sure, you could also use for example the proprietary inverter interface to do this (Hoymiles can do this pretty granularly, down to microinverter if not port level), but FW seems OK too.
 
Try configuring XW to stop frequency shift at 61.25 Hz, regardless of whether it was successful in curtailing AC coupled PV.
That should force it to stop before IQ8 goes down for the count. Maybe IQ8 is just too slow to ramp down.

Try configuring XW to much slower frequency ramp. Gives IQ8 more time.
 
Hedges said:
Try configuring XW to stop frequency shift at 61.25 Hz, regardless of whether it was successful in curtailing AC coupled PV.
That should force it to stop before IQ8 goes down for the count. Maybe IQ8 is just too slow to ramp down.

Try configuring XW to much slower frequency ramp. Gives IQ8 more time.
Click to expand...
Would like to do this, but there are no controls in InsightLocal and XW-Pro firmware to do this, or I don't know where to find them.
IQ7's are much faster than IQ8's responding with a ramp down to a raise in frequency.
 
What does it take to get an IQ8 working?
If somebody sent me one and all I have to do is connect PV and AC, I could try exercising it on Sunny Island, document its behavior.
 
No need for combiner AFAIK.

Did not know about the MC4 adapter. Dunno if a special disconnect tool is needed for it.

The trunk cable, you can probably find extras on Craigslist. I think there are some special widgets like end of branch terminators… or you could electrical tape/wirenut it up.

www.renvu.com

Enphase Branch Terminator for IQ Series Q-TERM-10

DetailsEnphase Branch Terminator for IQ Series Q-TERM-10Part #: Q-TERM-10Terminator cap for unused Enphase Q CableSold IndividuallyFind below how the Enphase IQ Branch Terminator looks installed with the rest of the Enphase IQ System:Find other related IQ Enphase System microinverter components...
www.renvu.com www.renvu.com
 
Hedges said:
Something like this?

IQ Cable Single Drop (Landscape, 72 cell) | Enphase

enphase.com enphase.com

Then apparently I cut and splice that in a junction box.

No combiner need? If I'm not accessing data?

IQ Combiner 4 | Enphase

enphase.com enphase.com


Plus this for MC4

Connector - DC Plug Assembly | Enphase

Find the perfect DC plug assembly connector for your solar system. Q-DCC-2 is an adaptor that connects DC output PV Modules using MC4 to IQ Series Microinverters.
enphase.com enphase.com
Click to expand...
Older versions of the IQ needed that converter pigtail to MC4, modern versions now have MC4 standard as DC input.
Screenshot from 2023-11-17 08-49-57.png
vs
Screenshot from 2023-11-17 08-50-54.png

Just give it 240 & PV panel and "it will work" [famous last words]
At startup there will a RED led for 5 minutes and then it will turn orange, meaning it found the grid but no communication with an envoy/communication gateway.
With communication it will turn green.
If you want to set grid profiles etc you will need an envoy to do so.
 
What was the point of the DC adapter? To make it slightly easier to work with non MC4 panels while also getting Enphase more revenue from selling yet another custom cable?
 
zanydroid said:
What was the point of the DC adapter? To make it slightly easier to work with non MC4 panels while also getting Enphase more revenue from selling yet another custom cable?
Click to expand...
Since the cable was included with the inverter, I don't think revenue was the reason.
 
zanydroid said:
What was the point of the DC adapter? To make it slightly easier to work with non MC4 panels while also getting Enphase more revenue from selling yet another custom cable?
Click to expand...
I have more than 1 MC4 connector go bad. If you need to reconnect them a couple of times, one might fail.
Having a removable pig tale with an mc4 will make you can get a new pig tale instead of a new micro inverter.
 
fromport said:
I have more than 1 MC4 connector go bad. If you need to reconnect them a couple of times, one might fail.
Having a removable pig tale with an mc4 will make you can get a new pig tale instead of a new micro inverter.
Click to expand...
Oh right, Enphase MC4 is right on the body and not changeable? I messed up one MC4 on my non Enphase micro during install, fortunately it was on a pigtail so I could just lop it off and crimp on a new one.
 
fromport said:
I have more than 1 MC4 connector go bad. If you need to reconnect them a couple of times, one might fail.
Having a removable pig tale with an mc4 will make you can get a new pig tale instead of a new micro inverter.
Click to expand...

Like using SMA "connector savers" on instruments. Brass connectors good for 50 mating cycles, stainless 500 cycles.
With the connector savers, could reach 2500 to 250k uses before the instrument has to be sent in for repair.

I've got some REC 325W panels with Stabuli MC4 so I'll use those for the tests. Couple of them in parallel and oriented differently for flat power curve during the day.

I'm hoping my scopes support "track and trend" which would let them graph calculated signals like frequency and RMS current/power. Otherwise, 2Meg samples and transfer to PC for processing (an excuse to try the free version of LeCroy's "Maui Studio", the software of their scopes.) I've been learning about features watching Teledyne-LeCroy's free webinars, and at least some of the functions are on my Tek TDS-784D scopes.

It'll be slow going in spare time, but hopefully I get scope traces and come up with parameters that make these things work. Using Sunny WebBox to configure Sunny Island I should be able to alter frequency limits and ramp rates, find how the microinverters can respond. Offline from the house, so the Official Loads Tester doesn't get annoyed (except by my absence, having disappeared into my dark cave.)
 
400bird said:
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.
.
Click to expand...
You're correct, the XW is raising frequency and voltage to stop micros from producing, anything is allowed in off-grid mode, no regulations to be complied with. This is not a violation of the on-grid behavior according to the selected grid profile. The 62 Hz applies only to on-grid.

The Hoymiles PV backfeed into off-grid was around 1200W - much higher than the 300W I was using for testing IQ inverters - when the frequency jumped to 66 Hz off-grid. As you've said, the XW will do anything to curtail production to prevent a shutdown.

XW uses the selected on-grid profile as a starting point for off-grid operations. I can change the various power curtailment properties, but it is not clear if the changes apply also to the on-grid profile or only to the off-grid use. Have an inquiry into Schneider SE to get clarification.

There was a 1 sec delay how the XW would respond to a power curtailment. I have set it to 0 and redoing all tests, getting much better results with frequency shift. Need to wait for full PV production on Sunday to repeat the Hoymiles test.
 
zanydroid said:
Hmm so if they removed the configuration does that mean there is no control at all on the XW side, and any tuning has to be done on the inverter side? Does it perhaps use the grid profile set on the XW as the frequency shift limits? As a zero export battery inverter not participating in assisting grid I don’t think XW needs to comply with any F-W function.
Click to expand...
I re-installed the latest firmware for the InsightHome gateway and can modify the grid profile properties as shown in the AC coupling guide and the latest XW manual.

Changed p(f) PreDisp to a 10 point non-linear curve starting at 60.1 and stopping at 62 Hz. Also changed response delay from 1 sec to 0. Big difference in AC coupling. The single IQ8+ inverter test at 300W with no load runs fine for any SOC from 90% to 98%, not much difference. At 61 Hz the IQ8+ shuts off and it always restarts after 5 minutes. I do see slightly higher shut-down frequencies with higher SOC, nothing significant.

SOC is not an absolute measure, SOC of 90% for a 5 kWh battery leaves 500 Wh for charging, while SOC = 98% for a 50 kWh battery allows 1000 Wh charge reserve.

There are properties in the MODBUS specs for power gradient over time, but I have not found them yet in the InsightLocal GUI,.
Would be great to specify FW power curtailment over time.

What is missing is a definable SOC hysteresis, it is 1%, causing frequent "nuisance" cycling.
Planning to test power curtailment tied to battery voltage, there is a definable hysteresis for the on/off curtailment voltage.
 
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