Dc voltage fluctuating on ve bus

Don’t know if anyone has experienced this I’ve got a Multiplus-ii 48v coupled to x2 pylontec batteries. Ac in is bi directionally in ess mode, everything has been working fine for about 9 months , but now the dc voltage is fluctuating on
Ve bus and now the multi won’t charge or discharge the batteries because of the low voltage alarm.
All cable’s have been checked and double checked no fault found
Any help gratefully received.

Post a few screenshots of your ESS settings …
It could be that one of your two Pylontechs is so out of SOC balance due to lack of charging that you now have a shutdown.
When was the last 100% charge?
Show the message from the Remote Console / Devices / Pylontech / Details