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| The ACR with its secondary wiring |
It's easy for us to think of the ACR (Automatic Charging Relay) in terms of its primary function - joining the house bank to the reserve bank, so that both banks may be charged by a single charging source, for example an engine or a battery bank, at the same time. Likewise, when it comes to wiring the ACR, it's easy for us to think first of the large cables that join the house bank to the reserve bank via the ACR. It's important, however, for us not to overlook some other wires that serve an important function for the ACR. In this posting, the second part of a two-part article, I describe how I created and installed these small secondary wires for the ACR in
Oystercatcher, my Ericson 25.
Let's begin by looking at the back of the ACR. Between the two red positive cables we see a Blue Sea Systems label. At the bottom of the label there are three abbreviations - GND (Ground), SI (Starting Isolation), and LED (which stands for the LED indicator light). In this posting I will focus only on the Ground and on the LED. I will not address Starting Isolation, a function which isolates the ACR from the battery banks when the engine is being started. After a discussion with a helpful tech support person at Blue Sea Systems, I determined that Starting Isolation was not necessary for my set-up. Starting Isolation, this person said, was a function that large sport fishing boats with large engines typically employed, not sailboats with small engines or motors.
First, let's talk about the LED indicator light. The purpose of this light is to indicate to the user that the ACR is recognizing a charging source (for example an engine or a battery charger) and is in the process of combining the two different battery banks for charging. I knew this would be helpful information, so I knew I wanted to make use of this LED function on my boat.
There are many LED indicator lights available on the market. When asked about these, the tech person at Blue Sea Systems told me that the Blue Sea Systems ACR needed a Blue Sea Systems LED indicator light in order to function properly. He said it all had to do with the milliamps of the Blue Sea Systems LED. Based on the numerous helpful conversations I had had with this tech support person at Blue Sea Systems, I took him for his word and did not experiment with other brands.
I was, however, tempted, because I knew that the Blue Sea Systems LED indicator light was quite small compared to other brands on the market. Just how small it was, I did not know for sure until I received mine in the mail from an online retailer. This thing was incredibly tiny. In the picture we see my Swiss Army knife beside it for comparison. Try to ignore the packaging and the wiring and instead focus on the small green bulb.
The instructions on the back of the packaging said that the light would fit in an 11/64 inch hole.
I began by drilling an 11/64 inch hole in a scrap piece of wood, just so I could see what this tiny light looked like by itself.
Are you squinting? Yes, it's that minuscule green dot at the center of the wood. Let's leave this problem aside for a while and talk about the next one.
Now I had to figure out how to route the wires for this LED. The positive wire, of course, had to begin at the ACR, but it needed to be routed upward, into the cockpit locker, and outward, into the galley, where most of the other major components of the electrical system were visible.
In the picture below, we see (L-R) the AC receptacle, the battery switch, the battery monitor, the DC main circuit breaker, and the AC distribution panel with the bilge pump switches above it. Somewhere on this bulkhead in the galley I needed to install this tiny LED indicator light. There was a small open space available to the right of the bilge pump switches, but putting such a tiny light in this space would have been silly. Besides, the backside of this area of the bulkhead was the least accessible from the cockpit.
After a fair amount of thought, I settled on the battery monitor. I decided I would install the LED indicator light on the mahogany panel, just beneath the monitor. Placing it here made the most sense to me, since the ACR, like the monitor, is related to the batteries.
With a center-hole punch I marked the spot where I needed to drill the 11/64 inch hole.
Slowly I drilled through the mahogany and through the two layers of the bulkhead, making sure that all wires that I had just installed in this space behind the bulkhead were not in the way of the drill bit. It helped that I could reach my hands through the adjacent empty holes.
Then I grabbed the LED indicator light and installed it in the 11/64 inch hole. Do you see it in the picture below? If you don't, you shouldn't feel bad. It's just a tiny green speck. I decided that this was unacceptable. I needed some sort of backer for this light in order to draw attention to it. In other words, this little fellow needed a lot of help in getting noticed.
I decided to use a small piece of 1/4 inch mahogany. This was a scrap piece from the mahogany I had used to create the decorative trim pieces for the battery monitor and other components of the electrical system in the galley.
I decided to use two finish washers for the screws. That way, this small piece of mahogany would tie in with the rest of the mahogany in the boat, almost all of which was joined with finish washers.
Next, I drilled an 11/64 inch hole and inserted the LED indicator light. Even on this small piece of wood this light did not stand out.
Therefore, I decided to use two differently sized stainless steel flat washers as trim pieces. Together they would look like one single finish washer, and they would help to draw attention to the LED.
This, I thought, looked much better.
Concerned that the finish washers on each side might be a distraction, I decided to get rid of them and instead drill countersink holes for flathead washers.
Then, I installed the whole thing.
I didn't like the way the flathead screws looked. They seemed out of place compared to all the other screws in the boat. Therefore, I went back and installed the finish washers. Below, we see them in place.
Now I needed to wire this LED indicator light. I had installed, as you will recall, the ACR in the lazarette. I needed run a 16 AWG (American Wire Gauge) wire up from the lazarette to the cockpit locker. In the picture below, you'll see that I have drilled a small hole and fed a red wire through it.
If you look carefully at the bulkhead, just to the right of the yellow wires, you'll see the small red and yellow wires for the LED indicator light. I needed to join the small red wire to the 16 AWG wire that I had just installed.
Before doing anything else, however, I needed to protect this red wire with some sort of sheathing. I chose white braided expandable sleeving. I had earlier purchased this from Genuinedealz / BestBoatWire in Brunswick, Georgia, USA.
In the picture below, you'll see that I have already installed the expandable sleeving on the ACR end of the wire. I should also point out that I have also already installed the quick disconnect terminal on the end of the wire. This heat shrink terminal I had also purchased at Genuinedealz / BestBoatWire. Same goes for the wire itself.
The braided expandable sleeving is easy to install, once you get the hang of it. When bunched up or wrinkled up, the sleeving wants to straighten itself out. Thus, by sliding your fingers over it and forcing it to wrinkle up, you can make it pass through small holes, just like the one that I had earlier drilled.
Next I focused on the ground wire for the ACR. For this I also used an adhesive lined heat shrink quick disconnect terminal. These female types of terminals are designed to fit over the male blades, just like the ones that Blue Sea Systems used on this ACR.
Over this yellow ground wire, I also installed white expandable braided sleeving. I routed this wire over to the grounding bus - the one on the far right of the picture. The black electrical tape on the end of the yellow wire does not protect some nick in the wire; rather, it protects the end of the expandable sleeving. In other words, it keeps it from fraying.
All I had left to do now was to deal with the small positive and negative wires from the LED indicator light. I needed to join the small red positive wire lead to the 16 AWG positive wire that I had routed up there. To join these two, I would use an adhesive lined butt connector. I also needed to join the small yellow negative wire lead to a 16 AWG yellow wire that I would rout to the nearby negative bus bar, yes the one with all of the yellow wires coming off of it.
Thinking that this was all I had left to do, I suddenly realized that I had forgotten to install fuse holders in the wires coming out of the ACR.
I began by installing a fuse holder in the ground wire. Why in the ground, you might ask, since fuses normally are installed in positive wires? I asked a tech support person at Blue Sea Systems this question. He said that their computer modeling showed that in the event of a catastrophic failure of the ACR, it would be good to have a fuse in the ground wire. Fortunately, he added, there were no known instances of catastrophic failures of ACRs.
I also, of course, installed an in-line fuse holder on the positive wire for the LED indicator light.
Here's a close-up of both fuse holders side by side.
My final task, after joining the 16 AWG red positive wire to the small gauge red positive wire lead from the LED indicator light with an adhesive lined heat shrink butt connector, was to create a 16 AWG yellow negative wire for the small gauge yellow positive lead from the LED.
Routing this yellow negative wire was easy, since a bus bar for negative wires was nearby.
In the picture below you'll see what I'm talking about. Notice that by this point I have covered the red positive wire (sheathed in white expandable sleeving) with a black plastic split-loom conduit. I did this so that it might be held more firmly in place by the large cable underneath which it ran.
All in all, the installation of the secondary wires for the ACR was not very difficult. As was often the case in the completing rewiring of this boat, the most time consuming task was trying to figure out how to route the wires and how to make all of the different pieces fit together into a coherent whole.
This ends this posting on my installation of the secondary wires for the ACR in
Oystercatcher, my Ericson 25.
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