Oddly enough I have almost the exact same issue and system setup. 2x200ah 12v smart lithiums and same victron components. We ‘turned off’ the system at 80% SOC via contactor on Smart BMS and a month later turned it back on. Both batteries were at around 5.6v and very unhealthy (alarms and bluetooth off on one).
I went through the same ‘recovery’ procedures and both batteries seems healthy again; but I’m trying to figure out what happened. Is there a massive ghost draw from the Smart BMS somehow? Have you found out what caused your batteries to go so dead? Have they worked OK now that you’ve fully charged them up again?
Thanks in advance!
John
<see topic Lithium Smart Batteries lose all charge in a month while disconnected? >