Tri-hull project Wiring

[drewpster]

I was asked to do a detailed post on the wiring I have done on my tri-hull project boat. As the time becomes available and the system gets more complete, I will detail what I have done.
The system is rather basic. My plan was to run the engine and boat accessories as seperate systems. The engine harness will be run independant from the boat fuse panel. I am using a single battery for now, but I have left plenty of room for expansion in the future. At some point I am going to add a trolling motor and install some electronics. For now I am concentrating on the basic system and the install of all the lighting.
I will have to get some photos together before I can be specific on how it is run. As always, the more experienced electrical guys in this forum are welcome to comment and point out any bonehead errors I am sure to make.

 

[Silvertip]

Re: Tri-hull project Wiring

At least you have the basic concept down, unlike many folks that just begin stringing wire and wonder why things don't work. You are very correct that there should be two electrical systems. One system works through the engine harness that runs from the engine to the console. That system obviously takes care of the engine, tilt/trim, and the instrument panel. The other system (house) consists of a pair (red/black) of 8 or 10 gauge wires that feed the fuse or breaker panel from which the various other accessories are fed. That system should have a 20 - 30 amp breaker at the battery positive post. From the fuse/breaker panel the sky is the limit. Knock yourself out. Trolling motors require a third system (12 or 24 volts) depending on the motor you install. And then there are dual battery switches, ACR/VSR, isolators, on-board chargers, and a host of other stuff that can be added. Just so you know, there is a sticky at the top of this forum titled "Generic Boat Wiring Diagram" that applies to the vast majority of boats in the same category as yours.

 

[drewpster]

Re: Tri-hull project Wiring

OK, I took a bunch of pictures and I am generally full of it, so here goes. As I stated before this part of the system is the main battery and the accessory circuits. The engine wiring is a separate harness and it will be added later. To prevent the thread from getting to complex I will concentrate on the basic layout. I will assume that you already have the basics of making connections and an understanding of the basic principles of a 12 volt electrical system.
In order to do the job correctly you need the right tools and components. I recommend only marine grade stuff to build the system. The specifics can be debated all day, but I am going with my own practical experience in servicing 12 volt chassis wiring in OTR trucking fleets for the past 20+ years. In short, bad wiring and corrosion are killers. Take every step you can to prevent problems ahead of time. Think in terms of what can go wrong instead of what will work and you've already won half the battle.

Battery
The main circuits consist of the battery, a main battery switch, a main breaker, a ground post and the main engine pos. and neg. cables.
The battery cables are short so I used 6 gauge marine cable to connect the battery to the battery switch and to the main ground post.

I know 6 gauge seems a little small but the run is very short from the starter to the battery and back. Based on all the ampacity recommendations I have researched, 6 gauge should be plenty. Even if the starter locked up the cables should be plenty to carry the current at this distance. The battery is a marine start 550CCA.

Main Distribution
I used a 1-2-both switch as my main power switch, a 40 amp marine breaker, and a main ground stud to make the connections here. (ignore the color on the ground stud-its ground I promise)

I used a 1-2-both to provide for expansion later. I intend to add a deep cycle battery for trolling and I would like to be able to switch to it when I want to.
The switch has three posts, no. 1, no. 2 and common. I used the number one post for the battery positive making the start battery number 1. All the loads are connected to the common post. When switched to number 1, the start battery powers everything including the engine. When in the off position, the battery is completely isolated.

Also connected to the battery switch common post is the positive cable that feeds the engine and a smaller 8 gauge jumper to the main circuit breaker that feeds the accessory fuse panel mounted under the dash.

The 8 gauge that feeds the breaker is really overkill in terms of size. I used it because I had it laying around. (also marine) 10 gauge would really be plenty for this little jumper. The breaker I used is a 40 amp resetable with a button that can be used to open (turn off) the breaker. This also acts as my main power switch to isolate all the accessory loads in the event of a problem. These breakers are also marine rated. The 40 amp rating is plenty to provide for the loads on the fuse panel. It is also a low enough amp rating to protect the main power wire in the event it has a short. tip- always rate breakers and fuses under the current rating of the wire at a given length and slightly over the total current needed to power all the consumers on the circuit. (total fuse panel load 30 A, 10 gauge marine cable at 12 feet 60 A= 40 A breaker)

Coming out of the breaker you can see the 10 gauge positive feed that goes to the main fuse panel mounted forward under the dash. Just behind and above you will notice the black ground that connects at the ground stud. The ground also travels forward to a ground buss bar also under the dash. It is duplex wire. (two wires in one jacket)

Accessory Distribution

At the other end of the 10 gauge duplex wire is the fuse panel and the ground buss under the dash. I mounted these under the dash because it is a good place to access the fuses and it provides a short run to the switch panel on the dash. (pay no attention to the color code, I had lots of duplex wire so I used it)

If you look closely you can see the 10 gauge red positive in the top feeding the fuse panel and the black negative connected to the buss bar. The fuse panel is a quality unit from Blue Sea systems. It uses standard blade type fuses. It provides 12 circuits in a compact panel and the fuses are readily available. (cover removed)

 

[drewpster]

Re: Tri-hull project Wiring

Accessory Distribution cont.

The ground buss is also a good unit from Blue Sea. It also provides 12 lugs on a common buss bar. I have plenty places for additional grounds when I need them.

On the right side of the fuse panel you can see the power feeds from the fuse panel to the switch panel on the dash. I use 12 gauge duplex wire. If I had it to do over I would have used 14 gauge. 12 gauge is overkill for this and it gets a bit bulky. (I had the 12 GA. on hand, again forget the color code)

Each switch is fed from its own separate fuse. I like it this way because if a fuse blows I can tell right away which circuit has a problem and only a single circuit is effected.

The switch panel is a Generation 2 from BEP marine. The downside to using this panel is that I could not locate a on/off/on switch for the Nav/ Anchor lights. I even called the factory direct and it was a hassle to get anything but off/on switches. That is the only problem I have found, it's a quality unit.

The switch panel comes with backlit labels and "on" indicators. I had to wire the Nav light and the Anchor light on separate switches. This could be a good thing in case one of them fails, but it was a compromise.

On the ground buss I connected all the grounds for each given circuit. The grounds for the gauges are also connected here. I ran all the wiring under the perimeter of the cap. It all originates from the switch panel to the lighting, including the panel backlighting. I love boating and fishing at night and I hated not having enough light. Ever try to tie a hook by flashlight..no more.
To run the wire I first installed strips of 1/2 aluminum angle under the gunnels. I drilled holes in the angle every six inches large enough to accept zip ties. Again I used quality UV stable zip ties to secure the wiring. DO NOT use cheap white zip ties.

Some of the smaller ones are the fancy colored ones, but they do not carry the weight of the harness itself. They are only used to secure single conductors or the LED lights I installed. (white and blue extra cool)

Look at all those ties! I intended to put all these wires in wire loom. But as it turned out it was not practical in this location. Here is a good shot at how I secured an LED strip.

 

[drewpster]

Re: Tri-hull project Wiring

wiring cont.

To secure the wires to the underside I used these wire retainers. They have holes also so screws can be used to secure them. I used screws wherever I could, I don't trust the pressure tape on anything but a smooth surface.

Here you can see the nav light wire secured under the cap. I used screws in each of the retainers in to the plywood. Notice the loop at the end of the wire where the anchor light wire passes through the cap? Its called a drip loop. If any water passes under the nav light it will drip off the loop instead of traveling up the wire to the connectors. Little details make the difference.

Here under the cap I used the same retainers to secure one of the LED strips. Again I used screws.

Well, that's just about it for now. When I figure out how to do it, I will route the engine harness, install the ignition switch and finish out the gauge wiring. I will add to the thread when that all pans out. I hope this gives an idea of how I like to do my wiring.

enjoy
drewp

 

[fish_on_the_deck]

Re: Tri-hull project Wiring

I think this is a great example of how to re-wire a boat. Nice, job and thanks for taking the time to document for others.

I like the blue seas products too... they are great.

One question... what brand LED strips did you choose? link? I'd like to see a pic of them at night too... thinking of this for my boat.

 

[tomynoks]

Re: Tri-hull project Wiring

I agree, great example of re-wiring! Perfect timing for me since that's what I'm doing this weekend. I have a question about the battery switch and whether I need or could use AFD (alternator field disconnect) I have an '84 Johnson 115 OB. I have been researching the internet and Iboats specifically, but I'm still not 100% sure. Any suggestions would be appreciated.

Thanks,

Tom

 

[LippCJ7]

Re: Tri-hull project Wiring

Good work Drew, Very nice!

 

[drewpster]

Re: Tri-hull project Wiring

I agree, great example of re-wiring! Perfect timing for me since that's what I'm doing this weekend. I have a question about the battery switch and whether I need or could use AFD (alternator field disconnect) I have an '84 Johnson 115 OB. I have been researching the internet and Iboats specifically, but I'm still not 100% sure. Any suggestions would be appreciated.

Thanks,

Tom

It is not necessary to use a AFD battery switch on your outboard. The field disconnect is used to protect an alternator in the event that the switch is turned off while the engine is running. The result in conventional remotely regulated alternators is that the alternator will go to full output and burn itself up.
Outboards do not use this type of charging system.

 

[drewpster]

Re: Tri-hull project Wiring

I think this is a great example of how to re-wire a boat. Nice, job and thanks for taking the time to document for others.

I like the blue seas products too... they are great.

One question... what brand LED strips did you choose? link? I'd like to see a pic of them at night too... thinking of this for my boat.

Unfortunately I just checked the link I was given to purchase my LED strips and it is no longer up. I assume the seller has sold them all out, or, got out of the business. I cannot vouch for the quality of the lights I bought. So far they are fine, but time will tell. If they start quitting on me I will change them out.

 

[JasonBo]

Re: Tri-hull project Wiring

I think this should be a sticky as the best example ive seen in boat wiring

 

[tomynoks]

Re: Tri-hull project Wiring

Hey fish_on_the_deck... you can get rope lights on ebay for $6.20 per meter...many colors..

 

[drewpster]

Re: Tri-hull project Wiring

I considered rope light as well. Seems like a good option. The downs I can see is the thickness of the rope itself. I also do not recommend one continous coil running around the boat. It will be way too bright. And make sure you get 12 volt LED rope light, not standard rope light. Standard will drain your batts.