Th3stig

I no longer have my VM3 but long story short, my comms issues back in January with the VM3/Dyness B4850 were caused by the battery software and not the VM3 as I assumed. I replaced the VM3 at the time but still had some comms issues with the new Growatt I replaced with until Dyness arranged for the battery software to be updated which sorted it all out.
I believe there were also circuit board issues with some of the late 2019 B4850 batteries and that Dyness have since replaced boards in these batteries. From my understanding of what caused the issues I had and what Dyness has changed since, you should not have the same issues  

I believe that the VM III uses the same version of remote display firmware as the Axpert King (with slightly different behaviour, as small parts of the code are unique to either VM III or King). So it might be worth trying removable display firmware version 02.49 for Axpert Kings (available from the files section of this forum). I have no idea what main VM III firmware is needed to go with this, but there is a decent chance that verse 41.14 (seems common in recently bought VM IIIs) will work. If not, you could request the latest main firmware (and display firmware perhaps) from your supplier. The display firmware handles all the interaction with the battery BMS. BMS direct connection is only available on 5 kW models. Dyness does not specifically appear on the battery type menu (setting 05), but there are 6 BMSs to choose from (including Pylontech).