hi!
For later reference: I spent quite a few hours trying to figure out what happens. The symptom was that the system was charging when the VE.BUS BMS Assistant was deleted, immediately when reinstalled the system gave low voltage warning and didn't charge.
It turned out that in my case the original Victron UTP cable was faulty between BMS and Quattro, we had to cut the ends end reclamp.
i hope i saved someone some time.
for other causes see: https://community.victronenergy.com/questions/14126/how-to-troubleshoot-quattro-not-charging-showing-f.html