Please advise. I have 2x two sets of batteries with BMS connected to the cerbo via BMS.Can and VE.Can. In the cerbo, the battery descriptions are displayed correctly. In the VRM, two batteries are displayed, but with the same description (name). In the device, there is only one battery with a description (name), which I connect last.
Dont know the battery type and bms, but normally you should connect the first battery to the bms can and the second needs to be slave of the first battery by connecting them together trough there link or rs485/can ports (see your battery manual)
Edit: Do i see 2 different batterys?? Thats not possible unless all specs are the same, but then you still cant have them connected at the same time! Only one bms can control the system
I don’t use BMS for system control, just for battery protection and monitoring.
i think you use bms for control,once it is connected,it is telling cerbo max current,max voltage,there is no way around it…you can see it in battery parameters…maybe use dbus-serialbattery and connect batteries to cerbo via !isolated! serial (jk has ‘rs485’ and gps connection-gps has better-obtainable connector maybe,both should be 3.3v serial),and i guess battery agregator is needed(software)-i have never tried it,but people suggested
edit:to be precise-control means telling cerbo limits=protection,i call it controlling,you call it protection?
In DVCC set without BMS and only limits set. The point is just that the cerbo shows correctly connected 2x2 batteries and VRM too, but with the same name. It’s really just a display, the system works exactly as I expected.
The set is always made of two batteries connected 485.
yeah,i now understand(need to properly read the pictures),you have pylon and jk…i have similar-pylon cells and jk bms 
what about battery agregator,have you tried? it needs to be installed from kwindrem’s setuphelper (and that is installed from usb and simple reboot),you get to it from gui-v1 only i think, it adds another bms,but it should contain all batteries…not what you want probably,but could help? the problem is jk acting as pylontech(you select it in jk protocol settings),so if you want to tinker,try another protocol? and maybe firmware update,if you have inverter bms,andy on youtube offgrid garage has some useful info(you probably know this)
and one more thing,there is some battery index i think,like battery number(in jk settings),maybe try that?..and out of ideas now…
Battery agregator It just combines two batteries into one…
I have the same problem:
1 Pylontech at BMS-Can, 1 JK-BMS at VE.Can.
Both are detected and shown correctly in the Cerbo Device List (with correct values).
But they have the same VRM-Instance ID (both 512).
So in VRM, there is only one of them shown. It switches between the two, sometimes showing the values of the Pylontech and sometimes those of the JK.
Node Red has the same problem.
I assue this is related to both having the same VRM-Instance ID, but I’m not sure.
And I could not find out how to fix this.
Thats because only one bms can be used, not two even if they are the same brand/model/type
But I had and monitored 3 BMS at the same time via USB and RS485. In the settings you can select which BMS is used for control.
Yes, there are multiple videos on Youtube showing systems with more than one BMS.
The problem seams to occur only if both are connected via CAN bus.
Seams that no-one has a solution for this problem. 
I will try to connect the JK BMS via RS485 next week (if I find some time) and then report here if that helped.
I connected the JK via RS485 (with SerialBattery Software) now while the Pylontech remains on CAN.
Works perfectly. JK now got VRMInstance 1. I can select it as “controling” battery. I can read it’s data in NodeRed and it is shown in VRM Overview below the primary (Pylontech) battery.
I think it’s a bug that both CAN batteries got the Instance 512, and this then causes all the other problems.