SW4048: Anybody AC Coupled able to charge batteries?

[MisterSandals]

I have micro inverters powering critical loads panel that feeds the AC Out of the SW4048.

With AC Coupled Mode enabled, its supposed to charge my battery connected to the SW.
No matter what the situation, it ONLY passes all the AC coupled power thru to the grid and never charges the battery.

I'd like to hear from anybody who has this working. Schneider not helpful.

I can turn AC Coupled Mode off and it does charge my batteries nicely. The problem then is that it stays in bulk charge mode forever which prevents the inverter from using the battery.

 

[BentleyJ]

Normally 100% of excess AC coupled power is fed back to the grid when its available. If the grid is down, of course excess power not consumed by loads must go somewhere which is into the batteries. When batt voltage reaches max charge volts then frequency shifting ramps up to shut down the AC Coupled inverter(s).

If AC Coupled mode is enabled can you at least manually initiate a Force Bulk Charge? What happens if you raise Recharge Volts to a value higher than the batt voltage? That should also cause a charge cycle to initiate.

 

[MisterSandals]

Normally 100% of excess AC coupled power is fed back to the grid when its available.

Not on the SW4048. Very different from the XW's. Schneider support cannot get past this difference and continually tell me how the XW works.

From SW Manual ( Download )


AC Couple Smart Charge
AC Couple Smart Charge is a feature of the Conext SW that prioritizes battery charging over energy export to local AC loads connected upstream of the Conext CSW battery inverter. AC Coupling must be enabled for this feature to be functional.

From the webinar:


See 29:00

 

[BentleyJ]

Sounds a lot like the mysterious Enhanced Grid Support feature that has been causing so many problems lately with the Pro.
Based on the wording regarding Smart Charge, "exclusively charged from the PV inverter". What happens if there is a charge controller connected to the batteries, Is the Smart Charge feature automatically disabled? Do you have a SCC in your system?

Not sure if this is helpful, just trying to read between the lines and make sense of it.

 

[MisterSandals]

Do you have a SCC in your system?

I do now but didn't when i discovered this bug. The SCC is directly to batteries so the SW4048 can only see battery voltage.

Is the Smart Charge feature automatically disabled?

Its a built in feature. It sounds like its turned on with the AC Couple Mode switch that "needs to be enabled", but so does "AC Coupling".
Of course the documentation does not address any of this.

Not sure if this is helpful, just trying to read between the lines and make sense of it.

I REALLY appreciate someone else looking at the wording. If I'm wrong, i hope someone tells me. But the wording, in more places than these 2, really sound like it should charge the battery.
Besides what else could the "smart" part possibly be? Read that again and look for any other feature let alone one that could possibly be "smart".

 

[MisterSandals]

Geesh, i just spotted a conflicting statement.
The doc says "AC Coupling" must be enabled.
The webinar says "AC Coupled Mode" must be enabled.

These are 2 different settings in different sections of InsightHome.

My head is going to explode.

 

[BentleyJ]

OMG, what's wrong with the people developing firmware, menu layouts and labels for these inverters and the various features. YIKES.

Let us know, what the difference is between those 2 menu items when you figure it out.

 

[hwy17]

I was hung up on how the inverter would even tell the difference between grid and grid tied inverter power, because it would all look like grid sign wave.

But I guess it would use the internal CTs and when it saw export then it would say "I'll take that" and try to zero out the CT with battery charging until it's batteries are satisfied.

And this would be to avoid charging from grid, that's the goal?

 

[MisterSandals]

I was hung up on how the inverter would even tell the difference between grid and grid tied inverter power, because it would all look like grid sign wave.

The AC coupled power comes into the SW4048 AC Out side where the critical loads panel is connected.

The grid comes into the AC In.

The SW4048 smart charge is supposed to monitor the AC Out flows: power coming in charges battery first, pass thru to grid second. Power going out supported by the inverter/battery and grid. Thats all the "smart" feature is supposed to do but it fails miserably.

 

[hwy17]

Newcomers must really wonder why we do this to ourselves when we pick Schneider lol.

It's for the quality ?. The frustrating quality.

 

[MisterSandals]

I found a REALLY well written document by Schneider. First one!

https://solar.se.com/au/wp-content/uploads/sites/3/2021/11/Solar-Installer-Handbook_Australia.pdf

See page 28 and 29 for an actual description of the AC Coupling Smart Charge feature.

I passed this on to the "support" team who mostly deny that this exists on the SW4048. But thats a black hole of "escalated" software bugs.

 

[400bird]

I keep expecting you to find that magical document that shows how to enable smart charge. What a bummer this is to hear, smart charge is a major differentiator between the SW and XW

Can you post a print screen of the SW settings?
Have you gone through everything on this set up page?
I'm not sure how different either of these pages is on an SW vs my XW.

 

[MisterSandals]

I keep expecting you to find that magical document that shows how to enable smart charge.

I can enable the AC Coupling Smart Charge just fine. I've narrowed it down to AC Support Mode (the setting necessary to actually USE your battery) breaks the smart charge. So you can either charge or discharge, never both (charge when AC coupling producing, discharge at night, never expecting this at the same time).
I have to manually turn off AC Support at 11 to charge then turn it back on at 4 to use my battery to support AC. 100% repeatable.

I'm open to try anything!

 

[400bird]

I can enable the AC Coupling Smart Charge just fine. I've narrowed it down to AC Support Mode (the setting necessary to actually USE your battery) breaks the smart charge. So you can either charge or discharge, never both

Oh, that's dumb. I didn't get it. So you have to choose between the two. It won't charge when PV is available and switch to discharge when loads are greater than PV? Very dumb.

What enables smart charge and grid support modes?

I'm open to try anything!

So, I've got this idea... How much celery do you have on hand??

 

[MisterSandals]

What enables smart charge and grid support modes?

The smart charge is a built in feature that is enabled when AC Coupling is enabled. I think what you call "grid support modes" is the setting i am referring to that prevents charging batteries (the gist of this thread) "AC Support Mode Enable".

It won't charge when PV is available and switch to discharge when loads are greater than PV? Very dumb.

Exactly! How could they get this so wrong?
When speaking with tech "support", i've quipped to fix the feature or change the docs to call it "AC Coupled Stupid Charge".

So, I've got this idea... How much celery do you have on hand??

I'm open for ideas! I'm not awake enough to figure out a celery funny... i could use a chuckle about now.

So today in my rush out the door today, i forgot to switch AC Support Mode off and missed a good sunny day to charge battery. We have a week of rain ahead so thats a bad miss that wouldn't happen if this bug didn't exist. Grrr.

 

[MisterSandals]

It has been an epic uphill battle. 2 cases closed inexplicably, 32 emails, a dozen lengthy phone calls, 6-8 support connections to my SW4048, and all the steps to reproduce this glitch 100% of the time...

I FINALLY hear back that they identified the bug. Its a whopper too. This bug would have likely disabled all the frequency shift safety features as well as rapid shut down. Absolutely positively never should have been UL certified or released.

The InsightHome (the only non-obsoleted way to administer these solar inverters) control for "AC Coupling" did not read or write the settings on the inverter. If this setting was enabled, which is required for all AC Coupled inverters for the above safety reasons, the inverter was never set but the value was stored in the InsightHome device and indicated in the interface (and config files!) the actual inverter setting.

The confirmation of my reported firmware bug was relayed to me, word for word:

" I was able to do some testing and located a bug in the Insight Home firmware where it is not correctly reading & writing the AC Coupled Enable setpoint on the SW inverter. Even though you can Enable AC Coupling in IS Local, the setpoint is still set to disabled in the inverter."

This is a whopper of a bug that has been swept under the rug for YEARS and what must have been hundreds (dozens? thousands?) of cases filed. Cases filed , brushed off and closed without any resolution.

My head is still spinning with amazement on how this could ever happen or exist for so long.

How many people counted on these safety features? How many of these Schneider inverters have been destroyed without frequency shifting? How many micro inverters? Many house fires or linesmen injured?

 

[solar8484]

The confirmation of my reported firmware bug was relayed to me, word for word:

" I was able to do some testing and located a bug in the Insight Home firmware where it is not correctly reading & writing the AC Coupled Enable setpoint on the SW inverter. Even though you can Enable AC Coupling in IS Local, the setpoint is still set to disabled in the inverter."

So a fix for the bug will allow the Smart Charging to work the way you wanted?

 

[MisterSandals]

So a fix for the bug will allow the Smart Charging to work the way you wanted?

Not sure. I got what I hope was more bad info:

“
The AC Coupled Smart Charge will only operate when AC Support features are disabled. This is by design so that the inverter bridge is available to assist the loads with battery power. When AC Support features are not enabled the inverter bridge is then available for charging instead of inverting.

When the grid is present the inverter will be in AC Passthrough, allowing the PV inverter to send it's power through the SW and out to the grid. You will only see the SW in "AC Coupling" when no AC input is present, and when the SW is absorbing surplus PV generation into the battery.”

I replied that this sounds insanely stupid and unnecessarily stupid for a design.
He’s tech support not an engineer, and has been mostly wrong about everything so a glimmer of hope that sanity prevails.

And I really want to see how my 4048 behaves with AC Coupling enabled before making judgement or next steps.

Do you happen to know what modbus register(s) are affected by turning AC Coupling” control?

Closest I can see is “inverter status” (0x004B, returns 1025 = AC Pass Through). Too many values for me to watch with my start using Node-red. I suspect multiple modbus addresses affected but I dunno.

I would like to set AC Coupling on asap so I can proceed.

Any ideas?

 

[400bird]

I agree that is the stupidest decision to build a great feature but then disable the option to both charge and discharge automatically on the same day. Not the first stupid firmware decision that Schneider has stuck to. See giving up on stacking SWs, not implementing smart charge on the XW, etc.

I suspect there's a single modbus register you could write to and enable/disable AC coupling. I don't have an SW, but I do have the 503 modbus map.

These settings look useful/interesting:


Reading the inverter or charger status would tell you AC coupling status indirectly, but there are plenty of other statuses. Reading 0x0134 seems more direct.

 

[MisterSandals]

I don't have an SW, but I do have the 503 modbus map.

This is perfect, thanks!!!

I was looking at an old modbus map. All set now.


Thanks again.