Fixed - Leisure Batteries Dropping Voltage Causing Split Charge Solenoid to Disengage

[Splurt]

Set off last Saturday for a 4 night trip.  Day one and the electrical gremlins emerge before we even make it to the first destination.  The leisure batteries intermittently drop voltage causing the fridge and radio to cut out.  Make it to the first wild camp spot late and as it has resolved itself I leave it alone.

Next day same again but anytime the fridge runs the compressor the batteries loose voltage and all connected electrical equipment cuts out.  When we get to our camp spot I spend the evening removing the seats, taking voltages and checking every connection convinced that I am going to find a loose connection that is making/breaking itself or shorting the batteries out.  I don’t!  Three hours and a few beers later we are restricted to using the led lighting only.  It’s ok, we are on holidays and there’s no point in getting annoyed.

The voltage reading across the leisure battery terminals was 12.95V at all times.  They are only two years old and have not had heavy use so I wouldn’t have expected them to fail.  The voltage from the positive terminal to ground was 3V.  The voltage from the negative terminal to ground was 9V.  I interpreted these readings as the presence of a positive to ground short circuit somewhere and when I couldn’t find one gave up.

My eureka moment came sometime in the middle of the night as they do!  A bad earth connection.  Next morning took the seats away again, disconnected the positive terminals and then removed the chassis earth.  The galvanised coating on the bolt appeared to have degraded.  It was now dull rather than shiny.  Wire brushed the bolt and mating surface so I had shiny metal visible.  Connected all up again, problem solved.

I should have known to start by checking the earth connections.  Anyways, the satisfaction of the fix by far outweighed any inconvenience and the trip was great from start to finish.

I have a solar panel set up that charges the leisure batteries when away and when not in use I have trickle charger connected.  I wonder has the prolonged electrical connection to the trickle charger caused the galvanised coating to change?  I don’t know if de-anodising is the correct term for this but maybe something along those lines.

[robertneill602]

Alloys used nowadays are notorious for corrosion. Not sure if Japanned (black) finish and the gold cadmium plated bolts are both the worst. Replacement with bright zinc/nickel plate seems to be in order.