Hi,
I had my brand new Cerbo GX and a BMV 700 connected to a 48V battery. The BMV 700 was connected to the Cerbo GX with a VE.Direct cable. Also a Multiplus II inverter was connected to the Cerbo GX using a VE.Bus cable. The inverter was connected only to the positive battery connection. At the moment I've connected the inverter to the negative battery connection, I've heard a spark like sound from the Cerbo GX. Since then is not working anymore. The fuse on the positive wire is ok.
Is this a wrong way to connect the Cerbo GX? Since the VE.Direct and the VE.Bus are isolated, it should not matter if I disconnect/connect the negative supply of the inverter (or any other connection on the inverter or on BMV 700). Then why has it been damaged by connecting the negative supply of the inverter?