Postscript on Battery Problem

I returned to the boat after a 10-day absence and was delighted to find all three battery banks at 14.2 volts.  I reported this to Bruce who opined that 14.2V was too high and might damage the batteries, and something around 13.6V would be preferable.  The only inputs to the batteries were from the wind generator and solar panels, so we suspected that one of the regulators was failing.  Because the solar panel's Victron MPPT controller is only a few years old the wind charger's controller dating from 2007 became the prime suspect.  

Bruce visited the boat two days ago to switch off the wind charger and found the batteries at a comfortable 13.7V.  Nevertheless he switched off the wind charger as planned to avoid the possibility of overcharging during the strong winds of the winter gales, and later in the year I'll try to run some experiments to determine if the controller is indeed faulty. 

The important thing is that the 5 large batteries on the boat appear to be fine.