When I came back to my boat after being away for 6 months, the voltage on my lead batteries was about 3V. I could not understand what had caused this, as everything except the BMV and the MPPT with solar panels was disconnected.
I bought new batteries, and then I saw that the BMV displayed 0,2-0,3V lower voltage than the MPPT. The BMV was tested by my dealer with same result, and has now been sent to Victron.
I had set the MPPT to use the voltage from the BMV, as adviced in the manual. I guess this means that the MPPT constantly thought that the batteries was not fully charged, and probably have overcharged them.
Does this seems like a plausible cause for the death of my batteries?