Sunday, January 1, 2017

Electrical system refit


The electrical panel of Mary Mar was quite a mess.  Besides having been constructed of plywood with hand cut (aka crooked) edges, the wiring was a rat’s nest, several of the meters did not work and it was only wired for a single 30 amp circuit.   It was also located near the entry door where it could be easily damaged by people walking by or where salt spray and withering sunlight could degrade and fade everything.  But the kicker was that you had to get down on your hands and knees to use the thing. This had to go.
The first thing we did was to move the location for this unit.  We definitely wanted to be able to use it standing up and about the only location which could enable that would be if you were standing at the foot of the steps down into the staterooms.  So we cut a hole in the wall and framed it out with a box. 


We then created our layout and built a backing panel to support all of the smaller panels that came with the boat but screwed into wood.  Instead of using analog gauges we decided to go all digital.  We also added a digital generator start/stop/monitoring device to the layout.

The original panels were screwed to the new aluminum backing plate and the whole thing was sprayed with gun metal grey.  Pin stripe tape was then applied and the original switches were installed.

The original unit flipped down in order to access the back side.  Again, it was a thing to behold for those who like to kneel before their work.  For us, however, the back of the unit has a removable wooden cover which is removed to expose the connections.  Everything is at eye height and it is a joy to work on this.  Also, the wood outer box gives us something to screw wires down to so this will be fairly neat and organized when finished; definitely not a rat’s nest of wires which cannot be understood.  Of course, the entire boat was rewired both AC and DC with marine grade electrical cable.
Given that this is an AC/DC electrical box it made sense to have the house battery close by.  So we removed the “night potty” from the side cabin and turned it into the location for the house battery and its switch.  Two 6 volt golf cart batteries are tied in series for this implementation.  The breaker is for the windlass.  The rotary switch allows the house batteries to be

  • disconnected from everything
  • connected to the charger and the DC breakers
  • connected to the charger, DC breakers and the engine starting batteries (requires their battery switches to be set to enable this).
So at this point we are keeping all of the batteries on the boat in shape simply by turning a couple battery switches to the right positions and then adding shore power.  The inverter / charger / ATS does the heavy lifting of managing what is going on relative to charging, inverting and shore power pass through.