Wiring layout at ground zero

[Dennis1958]

I have a Lowe Deep V boat Im decking out from scratch.

Im trying to determine how best to wire my boat before I deck it out. I will have a troll motor in the front which I was thinking of putting the battery for that under the front deck instead of all the way in back.

I will have 2 depth finders.

I have the 2 lights of course that will be at my concole.

I have the livewell that I will be needing electric to. My
boat has a water hole in the bottom but no pump so any suggestions on how to set that up would be helpful. The
hole is on the bottom I was told after I get done fishing and run back to the dock the live well will empty when the boat raises....

The back bilge pump..its a small one ...

Where should I locate the fuse box or should I just run inline fuses for everything?

Anyway.. Im starting from scratch so HELP

 

[Silvertip]

Re: Wiring layout at ground zero

Start with the trolling motor:
Battery up front. Two wire receptacle for trolling motor. Circuit breaker at the POS terminal on trolling motor battery. Largest deep cycle you have room for. Run your front locator off that battery if you wish since its closer than console. Install an on-board smart charger to charge trolling motor battery at the dock. Unless you have a high output alternator and make long runs the engine alternator will not be able to fully charge a deeply discharged battery in short runs.

For the remainder of the system, use a fuse or breaker panel at the console. Run heavy gauge red (positive) and black (negative) leads from the starting battery to the panel. Wire your lights, gauges, and accessories to the panel. Avoid in-line fuses as it makes for messy wiring. Again, circuit breaker or fuse at the start battery. The rating must not be greater than the capacity of the wire. Wire and breaker must be capable of carrying the total load for the engine and everything wired at the panel. Use marine wire and quality switches.

 

[Dennis1958]

Re: Wiring layout at ground zero

Start with the trolling motor:
Battery up front. Two wire receptacle for trolling motor. Circuit breaker at the POS terminal on trolling motor battery. Largest deep cycle you have room for. Run your front locator off that battery if you wish since its closer than console. Install an on-board smart charger to charge trolling motor battery at the dock. Unless you have a high output alternator and make long runs the engine alternator will not be able to fully charge a deeply discharged battery in short runs.

For the remainder of the system, use a fuse or breaker panel at the console. Run heavy gauge red (positive) and black (negative) leads from the starting battery to the panel. Wire your lights, gauges, and accessories to the panel. Avoid in-line fuses as it makes for messy wiring. Again, circuit breaker or fuse at the start battery. The rating must not be greater than the capacity of the wire. Wire and breaker must be capable of carrying the total load for the engine and everything wired at the panel. Use marine wire and quality switches.

What gauge would you reccomend to run from the fuse box to the battery? I saw a diagram using 2 fuse boxes but I dont understand what that was about.

 

[ricksrster]

Re: Wiring layout at ground zero

I would run 10 AWG. Think of the future. I have a "cigarette" lighter to charge my cell phone. Now I also want to use it to run a pump for the tube. I have to get 15A fuse now.
Two fuse blocks could be used for: 1) direct from battery and 2) 12V POS from ignition.

 

[jlinder]

Re: Wiring layout at ground zero

When picking a guage of wire you also need to consider voltage drop that occurs in the wire. How long will the wires be?

Unless it is long, 10 guage will carry 30 amps. Probably OK, but if you are doing this from scratch check on the cost of going to 8 ga. If it is not too much it would be a nice upgrade.

Dennis is right, you never want the fuse to be bigger than the current capacity of the smallest component it protects - wire or device. If you run 8 ga to a fuse block, you want a 40 amp fuse by the starting battery. (The fuses/circuit breakers in the block will protect any wires coming out of the block).

There are also 3 very important things you also need to do.

1. Documentation
2. Documentation
3. Documentation

Make complete drawings. Keep a copy on the boat and at home. If you do it on the computer you can reprint drawings at any time.

Label the wires clearly. Not only where it goes, but number each wire with a unique number. You would be suprised as to how confusing it can get when you come back a year later.

 

[Dennis1958]

Re: Wiring layout at ground zero

Are there any books or web sites that show the layout of a 16 ft boat ? I do understand the basics of wiring but this is a bit of a step up from that...but I look forward to the challenge.

As far as cost of wire..I dont have that much wire to get so if 8 is best I will get 8, but can you get to big a gauge wire? Is that just as bad as to small?

 

[Silvertip]

Re: Wiring layout at ground zero

You don't need two fuse panels. Just make sure the fuse panel you buy has a ground buss bar in it. This is where all of the ground wires get connected. Also use a fuse panel that uses the flat plastic auto style fuses not the glass AGC style.

 

[jlinder]

Re: Wiring layout at ground zero

No, there is not problem with big wire. You could run heavy welding cable if you want. Two needs for a minimum size of wire: It has to be able to carry the current without overheating (think fire), and you want to minimize the voltage/power lost in the wire (voltage drop).

After a certain point bigger does not help, but it does not hurt.

 

[Dennis1958]

Re: Wiring layout at ground zero

So what gauge wire and fuse size is usually used for the following items? My boat is 18' long.

LIghts , Bilge pump with auto switch, troll motor,
fish finder, livewell, cigarette lighter running a spot light
Cd Player (this is for my wife...go figure).

 

[tommays]

Re: Wiring layout at ground zero

I have a 50 AMP breaker that supplys a fuse pannel it runs everything nicely

BUT i think you will need to do the trolling motor on its own


Tommays

 

[Silvertip]

Re: Wiring layout at ground zero

You need to determine the current draw for each of those items. Bilge should have its own fuse as should the fish finder and live well. What you plug into the cigarette lighter socket determines how it needs to be fused. CD player takes very little current. The spot light takes a bunch. 10A should be adequate. Just be sure you use wire that can take 10A of current or it becomes the fuse and not the fuse..

 

[jlinder]

Re: Wiring layout at ground zero

I would run the trolling motor on a separate feed from the battery.

As for the rest, look up the specs for each component you have, then add some for expansion.

Make sure the fuse/breaker panel you buy will support that, then run a wire that will support the panel and fuse according to that.

Maximum fuses for different size wires:
6 ga - 60 amps.
8 ga - 40 amps
10 ga. - 30 amps
12 ga - 20 amps.

The next consideration is voltage drop. With an 18 ft boat I would guess you have about 15 ft of wire each way back and forth from the battery to the panel. There are voltage drop calculators on the web. Try http://www.stealth316.com/2-wire-resistance.htm for one.

You want to keep the voltage drop under 10% or 1.2 volts, but remember that the panel is only part of the circuit. You still need to run wires from it to the device. I would look toward keeping it lower. Maybe 5% or less (6 volts).

Using the voltage calculator and using 40 amps as a max (fused) circuit, you could use 8 ga (0.76 volt drop) but 6 ga would be better (0.48 volt drop)

I used 40 amps is just an example.

 

[Dennis1958]

Re: Wiring layout at ground zero

So from what I'm reading here ... It would be best to use 6 guage wire from the battery in back to the fuse panel under the console. Then look at each items amps I connect to determine my wire guage for those.
Is it ok to use 12 guage for the front and back lights? or should I use 10 guage for everything? Can using to big a guage wire cause me problems down the road?