new wiring

CNT

Petty Officer 2nd Class
Joined
Aug 26, 2019
Messages
157
I checked online (and YouTube.com) for BASIC wiring on a 12' boat. Most return with "two/three batteries" and complicate wirings with 10 switches. I just want redo BASIC with one 12v battery. Basically I am looking to make it neat and "safer". Since I never used a fish finder (it came with the boat and haven't used it yet either). I plan to take the boat apart and strip the old paint, repaint (proibly with garage floor paint with grey and black dots).

So, here's the "stuff" to connect to the battery. Do I need a "main" switch? I would need a small panel. I already bought these disconnects (both female and male, 8AWG) for the motor. I would like to put a fuse (what size?) somewhere too. I have a 15HP Mercury (2-cycle, with electrical starter) and some tolling motor that I forgot what they look like (in the attic). I may get a used tolling motor down the road, but it's not going to be like those high ends 55lbs (I don't know yet, it's still a 12' boat for a river fishing). I am like to make sure about wiring it right with big 8AWG wire to a panel and then small tiny wires for the lights and fish finder, not to overheat the wires.

Looks like I want TWO switches (one for boat floor light as in image and another one for both navigation lights front and back (or should it be two separate switches)) and the female disconnect, all on one plate mounted on the back corner of the boat. What about the fisher finder (Humminbird 197c), should that have a switch too? I might end up getting a different (color) fish finder after I learn with this one first.

If there's a thread here or YouTube on that (again, BASIC one battery, 2-3 switch), I would appreciate links.
 

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gm280

Supreme Mariner
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Jun 26, 2011
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14,604
When wiring anything, be it a boat, car or anything, you first find out what each circuit will draw in current. If the navigation/anchor lights draws two amps, then I would fuse or circuit breaker that circuit with a 5 amp fuse or breaker. Never use a lower fuse or breaker then the total amperage needed. You will never get it to work for any length of time. BUT, you also have to make sure the wires you are wiring with can equally carry the current you need as well. Typically the navigation/anchor lights are one switch with a center off position (DPDT center off or on/off/on). One way is the anchor light only, and the other way is both anchor AND front navigation lights. And since you are talking about wiring a boat, I suggest buying the proper marine wiring. It is plated wire specifically used for marine wet conditions and will last so much longer. As for the number of switches you need, that depends on how many circuit you will use. I like a separate switch and fused circuit for each item. That way if you do blow a fuse or pop a breaker, everything else will still work. Hope this helps you some. Any more questions, post them for sure...
 

CNT

Petty Officer 2nd Class
Joined
Aug 26, 2019
Messages
157
2004 Mercury 15HP EH

Since this motor has electric charging back to the battery, I wouldn't want that to be "charge" back to other accessories (lights, tolling motor, fish finder, etc). Correct? If correct, then how this is to be wired? Direct 8AWG wire from battery to disconnects to motor, nothing involve in between. Then another wire (size?) from battery to wire panel (fused somehow) for rest of accessories. Is this the correct setup? BASIC question? No relay for that setup?
 

Bondo

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Apr 17, 2002
Messages
70,954
2004 Mercury 15HP EH

Since this motor has electric charging back to the battery, I wouldn't want that to be "charge" back to other accessories (lights, tolling motor, fish finder, etc). Correct? If correct, then how this is to be wired? Direct 8AWG wire from battery to disconnects to motor, nothing involve in between. Then another wire (size?) from battery to wire panel (fused somehow) for rest of accessories. Is this the correct setup? BASIC question? No relay for that setup?
Ayuh,..... The feed wire for the accessory panel can pull off either side of the master cut-off switch,.....
The battery side will be Always hot, 'n the starter side will be switched power,....
 

CNT

Petty Officer 2nd Class
Joined
Aug 26, 2019
Messages
157
attachment.php


I think I finally found the diagram. I did all those searches and now this comes up. Anyway, (according to this diagram) looks like the "thick" wire would be my 8AWG wire and the rest for accessories is 10AWG.

What about the tolling motor? Would it be another "thick" wire (8AWG?) from the black connection port?

I still need help with fuse sizes.

Nav light = ___ size fuse
Stern light = ___ size fuse
15HP motor = ___ size fuse
Fish finder = ___ size fuse

I don't have the manuals and don't get much details from the internet (in fact, internet makes you pay for to download manual, if they are really manuals). I would appreciate some ballpark on fuse sizes.
 
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