Stacking of JK BMS

[MeinhardSchneider]

Hello,

I have a problem stacking two JK BMS.

I have two battery cases from EEL, one with a JK-PB2A16S-20P, the other with a JK-PB2A16S-15P.

I use the USB to RS485 adapter supplied by JK. This is connected to my Cerbo GX. If I plug a patch cable between the adapter and one of the two cases, I can retrieve the data without any problems. However, as soon as I connect another cable between the two cases (i.e. connect the two RS485-2 sockets), all communication is cancelled. It doesn't matter whether I connect the USB adapter in the first case RS485-2 on the left and then go from the right socket to the second case or whether I connect the adapter to the second case RS485-2 and then establish a connection to the first case.

I have addressed one case to 1000 (0x01) and the other to 0100 (0x02).

In the config.ini is entered:
MODBUS_ADDRESSES = 0x01, 0x02
BMS_TYPE = Jkbms_pb

Using the EEL app, I have set the protocol on the RS485-2 connection to ‘RS485’ (1) for both cases.

I have also built a short patch cable and connected a 120 Ohm resistor between pins 1 and 2 (orange and orange/white) to terminate the bus - no change.

Is there anything else I need to know to be able to query both JK BMS with a USB adapter?

Many thanks & best regards
Meinhard