MattS
Active member
Victron things can be quite clever, and I believe some of them do an occasional equalising charge where they do briefly charge at higher than normal voltage, I think it may be set to default at every 3 months (and that interval is changeable via their app if you can link your phone to the controller via bluetooth ).
If the controller hasn't had a chance to do the scheduled equalising charge because of lack of much solar power during winter then maybe it seized its chance when you ran the alternator ?
Can't claim to understand enough to know whether this is possible or not, but I do remember reading about the equalising charge and I could well believe Victron was clever enough to do it.