Fault F72 Schneider XW pro 6848 dual inverter

RWatsonRWatson Registered Users Posts: 1
My system is a dual inverter Schneider XW Pro 6848 with midnight solar 150 charge controllers. Off grid with Kohler 14resa 14kw generator and Schneider Conext AGS. Batteries are Fullriver AMG 830 Ah 48vdc, 39840 Wh (16 batteries) 

Question is when the backup generator starts, the inverter recognizes the generator by flashing a light on the inverter panel however after about 10-12 seconds the inverter shuts down with a fault F72 “external AC contactor fault. 

I’ve rechecked the wiring and checked all connections from the generator to the inverters and all seems well. I uncoupled inverter 2 from the system, disconnected all wiring, and restarted the system. When I started the generator it again faulted F72. I believe the fault is not related to the communication between the inverters as just running the main inverter it still faulted. I believe the fault is a stuck relay in the inverter itself. 

I’ve checked the programming in the AGS and it all seems correct. 

The system operates fine running off the 30 PV panels. The only issue is the fault F72 anytime the generator starts, either a manual start through the AGS or an automatic start through the AGS due to the batteries being discharged. 

I’ve been communicating with both Schneider Electronics tech and the tech from the company I purchased the system from. 

At this point Schneider is pointing the finger at the panel which the company I purchased the system from assembled and wired and of course the company I purchased the system from is pointing the finger at Schneider stating it’s the inverter. 

Has anyone came across this fault and if so what was the resolution? The only thing that makes sense to me is a relay in the inverter. Disclaimer: this is my first experience with solar and I am in over my head on this. Any help if greatly appreciated. I need to get this bugged out before the winter storms really get going. After a day or two of snow and clouds I’m stuck with dead batteries and no power. 


  • MichaelKMichaelK Registered Users Posts: 225 ✭✭✭
    I don't have the 6848 Pro, but the XW+ 6848.  The default setting for generator support is 140A, which is way, way higher than what my generator can put out.  When I want to use generator charging though, I set the initial charge setting to 10% (14amps), then as the generator warms up, incrementally increase the percentage up to about 32% (45 amps).  Once the generator has qualified the power at low output, it seems OK with continuing to accept power at higher levels.

    I have not seen this fault code, but my XW simply will not qualify my generator's power even if starting out at 32%.  It has to be started low, then inched it way up.  Your generator is big enough to handle that large a load, but maybe it needs the same inching up as mine does.  Try first setting it at a very low input, then see how high you can crank it up?
    System 1) 15 Renogy 300w + 4 250W Astronergy panels,  Midnight 200 CC, 8 Trojan L16 bat., Schneider XW6848 NA inverter, AC-Delco 6000w gen.
    System 2) 8 YingLi 250W panels, Midnight 200CC, three 8V Rolls batteries, Schneider Conext 4024 inverter (workshop)
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,150 ✭✭✭✭✭
    F72    External AC Contactor Malfunction Manual. The External AC Contactor was not set as expected. Check why the AC contactor has failed. Check for fusing of coil, wiring and connections. Verify that the AC contactor has power.

    This is not good ! One usually gets alot of warnings before this one. It is a common problem of not being configured correctly and running this way too long, or too many times. It is logged for warranty also to protect Schneider from inexperienced folks burning up the equipment.

    You may be lucky be cause this is so new. Look in Gateway for events recent, and history.
     You may not be lucky in that a 14kw genset can do some damage if XWP has not been configured properly or there is a defect in it's output.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
    E-mail [email protected]

Sign In or Register to comment.