Wednesday, 25 June 2014

New Electrics - 12V

Getting the boat back to England required mostly quick fixed to the existing system. Surprisingly, most electrics worked, and we learnt what a "torpedo fuse" is (found in old Italian cars and in older boats by young Italians). Some fuses would fall out every time the boat slammed into a wave trough, but it got us here. For more extended passages, it seemed appropriate to make sure the system is simple, reliable and maintainable. We installed LED lighting, replaced a lot of the wiring throughout the boat, and re-run all of it to the new heart of the electrical system - the switch panel above the chart table.
Old fuse panel (bottom)
New circuit breaker panel with 12V sockets and more
Previously, the electrical system felt a little "organic" - a battery on the starboard cockpit locker, another one behind the engine, the battery master switch only accessible by opening a locker lid (at sea!), switches drilled into the engine panel and the surrounding cockpit laminate, and a fuse panel below the companionway.

Having moved the batteries and simplified the high-current-cable runs, we installed the master switch above the chart table - to the left of the intended switch panel.
Master switch (rear view) with leads from/to batteries (bottom), engine starter (top right), battery chargers (top left) and switch panels (topmost)
The space available allowed the installation of the switch boards as well as navigational instruments. Having located a suitable faced plywood board, we chose the rough layout of the instrument panel.
Matt shuffling the instruments
Next, we made the cutout using a drill and a jig saw. The switch panels conveniently hide the mounting bolts for the negative buses - terminal blocks dedicated to negative (return) cables from varous lights and instruments.
Switch panels, GPS, depth display, voltmeter, test terminals
FInished cut-outs and mounting holes
The appliances connect to one of the two switch panels with resettable circuit breakers. Each panel has its own negative bus to keep pairs of cables organized neatly. The right panel provides two switched 12V sockets, and below the left panel we have monted a digital voltmeter display as well as a pair of screw/banana terminals - a convenient multi-functinal power supply right at the nav station.

To the right, we used the available space to flush-mount a GPS and a depth sounder display. The VHF and SSB reciever will remain beneath the deck to the left and right of the panel, respectively.
Back side
Negative buses for each set of switches
We took particular care to ensure reliable, long-lasting electrical contacts. All exposed cable ends are tinned, and all crimps are soldered to the wire to avoid any coming loose or corroding. We used screwed connections for all the higher current wires, such as the ones coming from/to the master switch and the chargers.
Adding wiring
Of all appliances, domestic lights are the most numerous, with three cable ducts carrying wires to all the light fittings along the center and either side of the cabin. These all come back to a single junction box behind the panel, with further junction boxes around the boat providing branching points.
It felt good to be finally able to illuminate the cabin and work after sunset without resorting to head torches.
Work on the nav station in progress
Matt working on the partition between nav station and cockpit locker

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