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The old ones had to be jiggled and messed with to get them to work, bad connections inside.  I replaced both switches, and all the wiring behind them.

This deserves a post of its own, even though it was just a big clean up project.

When we purchased the boat, I was most overwhelmed by the wiring of the boat.  It was utterly undecipherable to me, for months.  I spent hours looking at the original engine wiring diagram from Perkins, and the regulator wiring diagrams from Quad Cycle (no longer in existence, which didn’t help things).  Hours staring at the engine and cursing in frustration at the dozens of identical looking wires wrapped up in duck tape (rendering individual wires untraceable).  Yet more hours drawing up new arrangements and placements for bus bars and terminal blocks to organize things.

In the process of figuring it out, I discovered that it was made more confusing by a ton of extra, old wiring that lead nowhere, and also by some really fucked up wiring choices that had a single wire crisscrossing the engine room multiple times unnecessarily.  Piece by piece I discarded unneeded stuff.  There were two really big days, where I tossed enough garbage wiring out of the engine room to make a big rats nest pile in the cabin.  The old engine wiring was completely encased in ancient black electrical tape, which was all gooey and black, and all of the wires running to the instruments were at least 8 feet too long (no one bothered to shorten the wires as it came from the engine manufacturer, I presume).  The key switch, which is less than 3 ft away from the starter battery, was pulling it’s power from the starter solenoid across the room; twice a hot wire went an additional 4 ft past a perfectly functional terminal block, to be spliced into the middle of another wire directly under the wettest part of the engine.  I discovered the original alternator regulator hidden underneath the solenoid, with much of the wiring still spliced in place all over (this despite the fact that we have a nice regulator mounted elsewhere, with a backup regulator mounted right next to it).  The list goes on, but you get the idea.

Now it is organized, with clean connections, in the simplest arrangement that I could come up with, and it is reasonably easy to trace the wires when necessary.  And I drew up a big schematic of the whole shabang.

This was a hell of a job. First I’ll describe the original state of the panel.  The panel was set back 4 inches in the space, behind a 3 inch vertical piece of trim.  The panel was hinged at the bottom, so that when it folds down it hits the piece of trim, preventing it from opening less than halfway.  Inside the panel, all of the negative wiring was piled up on a single stud, with over 16 terminals stacked on top of each other, all corroding.  A handful of wires had pulled out of the terminals and were hanging loose in the compartment, only a few inches away from the hot stud.  It was unorganized, impossible to access and work on it, and a serious fire hazard. I took out the old panel and cut out the trim so that the new panel could be mounted at the face of the compartment (rather than 4″ recessed).  I constructed a new panel out of plexiglass from TAP plastics, laboriously drilling all the holes to accomodate the circuit breakers.  I put a piece of hardwood trip around the outside (coated with penetrating epoxy) and used a long piano hinge to mount it.  I used all of the old breakers from the old panel.  To make the common, hot side of the circuit breakers, I bought a strip of solid copper from McmasterCarr, and drilled out holes to match the location of the circuit breakers.  I bought tiny little screws from bowline and screwed the common hot side of each breaker flat against the copper bus bar.  I ran 0 gauge hot and negative cables to the compartment, mounting all the negative to the right and all the hot to the left.  The 0 gauge hot supply runs to a stud, and 3-4 gauge jumper cables connect from this stud to each of the copper bus bars on the back of the panel (there are three rows of breakers).  I mounted three terminal blocks on the left side of the compartment, to mirror the three rows of circuit breakers.  I used short jumpers of 12 gauge wire in as many different colors as I could find to make the connections from the circuit breakers to the terminal blocks.  These short jumpers are bundled into spiral wrap to tame them.  All of the negative wiring runs to a dedicated spot (very few stacked terminals) on two ample sized negative bus bars. The wiring remains loose in the compartment behind the panel, and looks completely disorganized.  But there’s plenty of space and it is simple to trace wiring.  I am concerned that if I bundle the wiring all up to make it look pretty, it will only make it more difficult to trace wiring.

We have about 6 120V outlets on the boat, that are powered either by shore power (when we are plugged in at the dock) or by our inverter running off the boat batteries (when we’re not).

GFCI outlets are the ones with a “test” and “reset” button in between the two plugs.  GFCI stands for “ground fault current interrupt”.  Here’s an extremely abbreviated explanation of what it does: it measures the current in and the current out, and if they don’t match, it trips.  If you stick your finger in the outlet, some of the “current in” doesn’t make it to the “current out”, rather it takes a route through your body to get back to ground.  The GFCI senses that current is going elsewhere, and trips.

GFCIs do not completely eliminate the risk of electrocution: they do not trip instantaneously (though they do operate very fast) and so during the millisecond that it takes for the GFCI to trip, you may have got enough of a dose to kill you.  They do, however, significantly increase the protection and safety.

You can get them from home depot–I think they’re about $7 apiece (not including the box to mount them in and the plate to cover the front).

The GFCI outlets were bulkier than the old outlets, so I had to cut out the mounting hole a little bit on every one (wouldn’t expect any less frustration from a boat project).

I made a diagram to show the basics of our setup.  Hot wiring is red for the blue highlighted option in the list.

The traditionally espoused sailboat wiring setup is not ideal for a sailboat that incorporates multiple charging sources.  The traditional setup uses two identical house battery banks and a single battery isolation switch.

The ideal setup uses a large deep-cycle high-capacity house bank and a small, inexpensive starting battery.  The reason we use two battery banks on a sailboat is so that we always have a charged battery that can be used to start the engine.   Identical house banks are an inefficient and expensive way to accomplish this goal.  Prior to the existence of efficient and affordable series regulators, the double house bank setup made more sense.  Now, we can use a $130 Xantrex Echo charger to siphon charge off of the house bank to the starting battery, with no danger of the starting battery becoming accidentally discharged.

The ideal setup uses two isolation switches.

These are the goals:

1) Ability to isolate current sinks from the batteries with a switch. Ability to isolate current sources from the batteries with a switch. Ability to isolate current sources from current sinks with a switch.

I was working on the electrical system with the main battery switch turned off, and was astounded to find that the lights (and everything else on the boat) still turned on.  I realized that the Freedom Inverter, plugged into shore power, was acting as a transformer to supply 12V to the boat even without the batteries in the system (the inverter is on the downstream side of main switch). I considered moving the inverter to the upstream side of the main switch, but then I realized that I wouldn’t be able to switch the inverter out of the system–it would be constantly connected to the batteries. The same reasoning holds true for other sources of current as well, including the alternator, the PV panels, and the wind generator. I do not want those things constantly connected, without a quick way (a switch) to remove them from the system when leaving the boat.

The solution is to have two switches rather than the traditional single switch. By installing the second switch in the ground return instead of the supply side, we have isolated both house and starting batteries at the same time. (similarly, by installing the 200A fuse in the return line we protect the 2/0 wiring with just one fuse, instead of one in each of the batteries + side.

2) Separate house bank and starting battery.

This is the most efficient and cost effective way to maximize capacity available for regular usage while maintaining a backup way to start the engine.

The starting bank is charged with the Xantrex echo charger; the Freedom Marine 20 inverter has one built in that will come online regardless of charging source (not just the AC). I ran the starter hot to the other spot on the main switch, so that in the event that the starting battery fails, the house bank can be used to start the engine.

3) Protect all wiring with as few fuses as necessary.

To this end, I have inserted the fuse for the 2/0 cable in the ground return rather than the positive side. If I had put it in the positive side, I would have needed separate ones for the house and starting batteries.