12v Battery Drain

I have a 2018 Smart passion. Received a notice from MB to come in for a BMS software update. Done on 12/14/21. When starting, ⁷noticed all kinds of system check warnings that eventually went away. By 1/23/22, warnings stayed on with another message to stop motor. 12v battery was low, so recharged to full - all system check messages disappeared and looks to be normal. Any thoughts on this would be appreciated.