MdCT

Good afternoon. I have the same issue running parallel 5KvA Victron MPII's with 2x 10KwH (SSS) batteries (issue since September 2021). From reading Victron forums it appears to relate to the discharge current at loadshedding. Small brownouts can occur resulting in a large draw from the batteries that can cause the BMS to disconnect. I have installed a voltage monitoring relay with contactor to cut off at say 210V, but this has not solved the problem. Apparently this is usually solved with additional capacity (which would also increase discharge current limit). Perhaps your system is undersized in terms of battery power? With 2x 12KwH inverters there can be a significant current draw upon grid failure. Others have used ESP's API and use Home Automation to automate disconnecting from the grid before loadshedding and reconnect shortly after... Unfortunately I haven't found anyone able to doing the MQTT / Modbus programming for this unfortunately. Happy to be corrected on my comments...