Hi all I've tried the search function but couldn't quite find something that matches my issue. I have a Growatt SPF 5000ES inverter connected to x4 Dyness B4850 batteries via RS485 (comms by CAN protocol L52) - no issues in this setup. I have since acquired x2 more B4850s secondhand and they don't appear to playing well together as a stack even after they been top-balanced. The x2 purchased recently have a visual difference to the x4 older batteries, in that they have x5 SOC lights on the panel in comparison to the x4 SOC lights on my original quad. When connected to my current system (with one of my original older batteries as the Master), the x2 "newer" batteries show all SOC and RUN lights flashing - which according to the handbook denotes a communication fault. Additionally, I can run the x2 newer batteries on their own just fine. If I set one of the "newer" batteries as the master for all x6 in a stack, the SOC lights for the "older" x4 batteries are out of sync and show varying SOC indications Any ideas? I presume they can be used together as they are the same model but I'm unsure if they have differences in internals or software (and unclear whether consumers can flash firmware updates). Any help would be much appreciated.