Hello everyone and thank you for accepting me to the forum. The system I have is about 1 year old 3 phase - 3x inverters on one phase and 2x inverters (EASUN is the same as Axpert MKS II, MppSolar, Alpha outback SPC II etc) per phase for the other 2 phases. Each inverter connected to a string of 10-12 panels (330 and 405W). Also 3 banks of 7x Pylontech US2000C. All was fine until last night when the system has shown 04 low battery alarm and went to the grid. All batteries were around 90%. In the morning when the sun was back it went off the grid and used PV, still flashing 04. I have reset inverters and batteries- everything was OK, until I disconnected mains grid and PV input - it run on batteries for about 20 minutes and stopped again. Batteries were at around 80-85% at this point. I was thinking the battery issue - so disconnected each battery bank in turns, but still the same. During the day batteries were charged back to full but when the sun was gone - system went back to the grid, not using the batteries. I have now reset the inverters and no fault flashes on display - but still would not use the batteries. Reset the batteries - invertors briefly connected to the batteries but went back to the grid within seconds. Now the last battery in each bank shown alarm for about 5 mins. Another thing, I have some strings of 12x405W (total 4,860W) - and the inverter rated max PV array 4,500W, but these panels never get 100% sun exposure so I do not think it is an issue. Also solar cables - some 4mm and others 6mm over 130 meters. Any thoughts or advise highly appreciated, cheers

Hello everyone and thank you for accepting me to the forum. The system I have is about 1 year old 3 phase - 3x inverters on one phase and 2x inverters (EASUN is the same as Axpert MKS II, MppSolar, Alpha outback SPC II etc) per phase for the other 2 phases. Each inverter connected to a string of 10-12 panels (330 and 405W). Also 3 banks of 7x Pylontech US2000C. All was fine until last night when the system has shown 04 low battery alarm and went to the grid. All batteries were around 90%. In the morning when the sun was back it went off the grid and used PV, still flashing 04. I have reset inverters and batteries- everything was OK, until I disconnected mains grid and PV input - it run on batteries for about 20 minutes and stopped again. Batteries were at around 80-85% at this point. I was thinking the battery issue - so disconnected each battery bank in turns, but still the same. During the day batteries were charged back to full but when the sun was gone - system went back to the grid, not using the batteries. I have now reset the inverters and no fault flashes on display - but still would not use the batteries. Reset the batteries - invertors briefly connected to the batteries but went back to the grid within seconds. Now the last battery in each bank shown alarm for about 5 mins. Another thing, I have some strings of 12x405W (total 4,860W) - and the inverter rated max PV array 4,500W, but these panels never get 100% sun exposure so I do not think it is an issue. Also solar cables - some 4mm and others 6mm over 130 meters. Any thoughts or advise highly appreciated, cheers