Electrical, Battery Switch, Part 2: Wiring

The battery switch, fully wired
Having described in the first half of this article my rationale for selecting the switch I selected and locating this switch were I located it, I will now, in the second half of this article, describe the approach I made to the wiring of this switch on Oystercatcher, my Ericson 25.
Let's begin by looking at the back of the switch. Moving clockwise from right to left, we see that the first terminal, is labeled with a number 1, the next terminal is labeled with a number 2, and the last terminal is labeled with the letters COM. I used the number 1 terminal for the house bank and the number 2 terminal for the reserve bank. Some people call this reserve bank the starting bank, but as I said in the first part of this article, I do not use it for starting purposes. Finally, there is the COM terminal. This stands for COMMON. In keeping with the instructions provided by Blue Sea Systems, the manufacturer of the switch, I used this terminal for two separate cables - the starting cable and the cable that joins the battery switch to the DC main circuit breaker.
For the wiring of this battery switch I used Almo brand battery cable that I ordered from Genuinedealz / Bestboatwire in Brunswick, Georgia, USA.
I benefited much from the excellent advice given by Maine Sail in his many postings on various sailboat forums and on his Compass Marine website, a link for which is on the homepage of this website. It was from Maine Sail that I learned about using the starting bank as a reserve bank, and it was from Maine Sail that I learned about Genuinedealz.
I was also from Maine Sail that I learned to use the largest battery cable possible, and it was from Maine Sail that I learned about FTZ brand heavy duty lugs. I estimated that 1 AWG (American Wire Gauge) was the maximum possible for the confines of my lazarette and cockpit locker, where all of this cable would go. This ended up being a very good estimation. I believe that if I had ordered a larger gauge, such as 1/0 or 2/0, then it would have been impossible for me to route it in the fashion that I routed it. I know that, in terms of the battery switch, I would not have been able to fit it in the tight space around the battery switch. 1 AWG was almost too large, and for some time I thought that I would not be able to make it work.
With the battery cable and the battery lugs in this package I received from Genuinedealz / Bestboatwire there were also many pieces of 12 inch adhesive lined heat shrink tubing that I had ordered.
Earlier I had ordered an FTZ brand crimper from K. L. Jack Industrial Fasteners & Supply in Portland, Maine, USA. Where did I learned about this crimper and this company? Yes, it was Maine Sail. I have no problems tipping my hat to him multiple times. I think he gives damn good advice, and I though I am not a marine industry professional, as is he, I share his penchant for precision and clarity, and I share his general dislike of sloppy, half-assed, bone-headed boat work.
With these and other items at my disposal, I created the cable that you see below. In my article on the wiring of the ACR (Automatic Charging Relay), I have described my crimping and sealing of similar cables, so I will not belabor these points here.
Making the cables was not the hard part. The hard part was figuring out how to route them and make them fit into such a confined space. As far as the cables for the house bank and the reserve bank were concerned, I had to route them down from the battery switch, into the lazarette, over the top of the ACR (the device with the yellow tabs), and then over to the top studs on the house bank and reserve bank positive bus bars (which I have labeled in the picture below).
As far as the starting cable for the motor was concerned, I had to route it down from the battery switch, into the lazarette, and then up again into the cockpit. Why, you might ask, would I route it down into the lazarette, only to bring back up into the cockpit? Because in the cockpit I had to be able to fit a protective panel over the wires and other components (such as the battery switch) on the bulkhead. Therefore, if I had tried to route the starting cable through the cockpit, it would have prevented me from installing the protective panel. For more on this protective panel, see my article, "Electrical, Protective Panel for Components and Wiring."
I also had to take into account the other cables (such as those for the battery charger) that I had to route through the lazarette. It took a lot of thought and time to figure it all out. If you look closely in the picture below (and especially if you look above, two pictures back), you'll notice a notch in the HDPE (High Density Polyethylene) backplane, i.e., the black plastic board. I had to remove the backplane from the weld studs and cut a notch in it, so that I could route the cables down into the lazarette from the cockpit. For more on this backplane, see the following article, "Electrical, DC Main Circuit, Part 1: Constructing and Installing the Backplane."
It took a while to figure out where to drill the holes and where to route each cable. In the picture below, you'll notice that I am using the cable for battery switch 1, in other words, the house bank cable, to test the flexibility of the 1 AWG cable. This is not the hole that I would use for this particular cable, and this is not even the right end of the cable. I had not yet crimped a lug on the other end. Having one of the ends uncrimped allowed me to pass the cable through the hole. Once I crimped a lug on this free end, there would be no turning back.
I also had to figure out how to route the 4 AWG cable from the COMMON post to the back of the battery switch. This was a short cable. Nevertheless, it was something of a pain to install. For more on this, see my article, "Electrical, DC Main Circuit Breaker, Part 2: Wiring."
There was also the issue of the bulkhead. There was a small gap between the top of the bulkhead and the hull liner cleat. This I filled with NP1, a polyurethane adhesive/sealant.
The benefit of using NP1 (which is marketed as a high-grade adhesive/sealant for the construction industry), is that it comes in a variety of colors, for example, Off White, and it is much less expensive than 3M 4200 and Sikaflex, which of course are marketed as "marine" polyurethane adhesive/sealants. The Off White in this application worked very well.
In the routing of these cables I would ultimately decide to crisscross the house bank and reserve bank cables in the fashion you see. I did this here to prevent myself from having to do something similar down below, in the lazarette. There was no getting away from having a crisscross somewhere, because the house bank bus bar on the backplane was outboard, and the terminal on the battery switch was inboard. Conversely, the reserve bank bus bar on the backplane was inboard, and the terminal on the battery switch was outboard.
In the picture below we see the battery switch as it appeared soon after I had completed the wiring of it. Due to the size of the 1 AWG cable, I was almost not able to fit the house bank cable (the cable on the far right) past the blue protective cover for the AC receptacle. For this reason, and for several others, 1 AWG cable was the maximum for this set-up. If I had tried to use anything bigger, it just wouldn't have worked.
Satisfied, I at last installed the red protective cover for the battery switch.
Then, to make things absolutely clear, I put a label on it. Call me what you will, but in the future this will make things crystal clear, not only to me, but also to anyone who might be assisting me with some problem.
Here's the way it all looked in the cockpit locker when I was close to the end of the entire rewiring project. Looking back on it, I find it hard to believe that I was able to fit all of this together in such a confined space. It was only through a lot of time, a lot of effort, and a lot of thought that this was possible. Sure I had made meticulous plans in advance, but none of these fully prepared me for the challenges that I faced when the time actually came for me to lay hands on this project. Just like sailing itself, the rewiring of a boat requires patience, perseverance, and an ability to adapt to ever-changing circumstances.
This ends this posting on how I wired the battery switch for Oystercatcher, my Ericson 25.

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