XW+ AC Coupling

[hogback]

I have an XW+ that I've been using off-grid for four years. Nothing wrong with it. I'm about to power the system down to swap to different batteries, and was perusing the operators' manual for refreshing my mind, and I saw this:

AC_Coupling AC Coupling function is enabled by default (Advanced Features Menu) and should remain enabled except in cases where the DC voltage level is allowed to have large variations and the AC line frequency needs to remain constant.

I'm assuming this term "AC Coupling" has nothing to do with and AC vs. DC coupled system (mine is DC coupled). I've read the description over and over and it is not registering for me. If this term has nothing to do with the common meaning of AC or DC coupling, is the just a poor choice of words on Schneider's part?

I also have an XW pro (two actually) that I've been playing with in the garage for a possible auxiliary or backup system. One of these seems fried (likely by me - it seemed fine when I first hooked it up - now all options are greyed out in insight local, so I can't even restore factory defaults. I had played around with SOC info from a BMS and might have set some things wonky. I had thought that I had set the AC Coupling option incorrectly). I do remember that there was a similar option for AC coupling in insight local for the XWpro, so I guess I'm asking what this setting is for and why you'd want to have it set one way or another, and what the ramifications would be with it set incorrectly one way or the other.....

Thanks in advance if anyone has any insight (pun).

 

[BentleyJ]

That warning is simply saying that if the loads on the inverter are sensitive to frequency variations then AC Coupling should be disabled. Reason being the inverter uses Battery Charging Voltage Set Points to determine when to start frequency shifting so as to curtail or shut off excess PV Inverter output.

If the DC bus is subject to rather large voltage fluctuations then you may experience nuisance AC frequency shifts that are not well tolerated by sensitive equipment.

 

[hogback]

So in a DC-coupled off-grid system, it doesn't matter or should be set to off? And would it affect AC in from a generator during that sort of charging?

 

[BentleyJ]

In your situation it probably doesn't matter if AC Coupling is Enabled or Disabled but I would Disable if its not needed.
Should not have any effect on either AC1 or AC2 Input if a gen were connected to either.

 

[hogback]

OK - I will check to see how it's set when I can drag my laptop out to the shed. Thanks,