Can't see the BlueSolar Charger Mppt 100/50 Ser.Nr. HQ153FGM1l Firmware v.150 on my Cerbo GX Firmware v2.54 the MPPT ist connected to the VE.Direct.
A BMV-700 connected to VE.Direct works fine.
The only difference that I found : BMV 700 gives 3.5V on the VE.Direct connector and the MPPT has 5V on the + connector. so also the data lines on the MPPT has an higher level than on BMV-700.