1 Engine 1 Battery setup.

[CalicoJack]

I am about to wire everything up and wanted to know if the basic electrical diagram I created looks correct (never done this before). Are the wire sizes correct?

I have a combination battery starter/Deep Cycle - kill switch - fuse box - switch panel - and just simple accessories to connect to the switch panel.
Thanks in advance!

 

[lckstckn2smknbrls]

Maybe a fuse in the cable from the battery to the switch.
As close to the battery as possable.

 

[CalicoJack]

Maybe a fuse in the cable from the battery to the switch.
As close to the battery as possable.

I have a 40A circuit breaker. Would that work?

 

[InSaneFisherMan]

I have a 40A circuit breaker. Would that work?
View attachment 116639

Probally not, just a guess, the way your wiring is, cranking motor + wire doesn’t need a breaker. A breaker at battery would be in the cranking wire path. You would have to connect the breaker and try starting your motor a few times to see if it trips.

I would definitely put a breaker within 7" of battery switch to fuse panel.

ABYC E-11 shows how to wire the CB with a switch, highlighed in green is probably what you need.

 

[InSaneFisherMan]

I am about to wire everything up and wanted to know if the basic electrical diagram I created looks correct (never done this before). Are the wire sizes correct?View attachment 116637

I have a combination battery starter/Deep Cycle - kill switch - fuse box - switch panel - and just simple accessories to connect to the switch panel.
Thanks in advance!

Wiring plan looks good, as previous stated a fuse/circuit breaker.

Seen a few boats filled with water (from rain) when the bilge pump is wired to battery switch and set to off. Just something to consider.

 

[Al U Minium]

I would say the first thing you should do is find out what size wire for the starter is required by Mercury.

#10 wire to your fused/breaker switch panel

I don't know what a combo battery is. Are you going lead-acid, Lithium, both?

Battery On/Off switch does not need to be fused if it is capable of breaking the maximum current from the battery

The wires to bilge, electronics, lights are usually already made up and generally #16 or smaller with their own in line fuse

Use a single point ground and all the ground wires go to that point

If this is a house boat with 100 feet of wire run in every direction, your wire sizes are good, if it's a16 foot run about with all the stuff at arms length, its over kill with the 4, 6 gauge wires

Most important with this is a good quality fire extinguisher for marine use (proper restraint bracket and gauge) in easy to reach location .

I like the reply quoting from American Boat and Yacht Council

do not solder wires, crimp connections only, ring terminals, no flag, stab, fork, 3 way, screw pressure and everything copper rated no aluminum

use a spray coating on all your open connections like LPS3 or Fluid Film, do not allow anyone on your boat with WD-40

 

[airshot]

How big is your battery capacity?? Do you spend a long time on the water running accessories ?? The reason I ask, is will you drain that battery after a day on the water so it won't start your motor ?? On all my boats that have had electric start motors, I use two batteries...one for starting the main motor only and the other battery for bilge pump and all electrical accessories In this way you always know your motor will start when time to head back in. Just some food for thought for ya !!

 

[thill]

I didn't read the comments, but no, it's not correct. You have a 6ga wire from the battery, feeding a 4 ga wire to the engine. If 4 ga is what is called for, it should go from the battery to the switch. I usually use a #2 wire for that duty.

 

[InSaneFisherMan]

When talking wire guauge, there’s not enough information in the drawing to make more than a guess. For short runs, the wire guagues appear to be good.

Length of wire and amperage rating needed for circuit would take the guess work out of it.

But according to E-11, there is little diffence between 4ga and 6ga when wire length is less than 10'.

 

[CalicoJack]

When talking wire guauge, there’s not enough information in the drawing to make more than a guess. For short runs, the wire guagues appear to be good.

Length of wire and amperage rating needed for circuit would take the guess work out of it.

But according to E-11, there is little diffence between 4ga and 6ga when wire length is less than 10'.

The boat is a 16ft Alumacraft. The battery is approx 3ft from the motor.
The motor cables don't have a AWG size on them.Infact they have no labeling whatsoever. I am guessing they are 4awg because they are slightly thicker than a 6awg cable I have (compared them next to each other the Mercury outboard cable is the faded one).

 

[DaleH]

Just all remember that for wire size ampacity calculations, a ‘run’ or the length is the distance TO the load and BACK. So the 3’ distance from OB to battery is really a 6’ ampacity run.

 

[InSaneFisherMan]

With th

The boat is a 16ft Alumacraft. The battery is approx 3ft from the motor.
The motor cables don't have a AWG size on them.Infact they have no labeling whatsoever. I am guessing they are 4awg because they are slightly thicker than a 6awg cable I have (compared them next to each other the Mercury outboard cable is the faded one).

Really need to compare center conductor for guage size, the insulation material could be thicker on one cable verus the other.

Just my opinion:

With the total lenght 6', I would put 4 guage on everything in the starting wire path both - & +.

I would put a 30a or 20a breaker at battery switch (not sure about bilge pump), but everything else probably uses less than 15a.

6 guage wire from breaker to fuse panel both - & + (total length of 20') would support up to 40a.

Not that fimillar with dual purpose battery, but it should work well.

 

[CalicoJack]

I would say the first thing you should do is find out what size wire for the starter is required by Mercury.

#10 wire to your fused/breaker switch panel

I don't know what a combo battery is. Are you going lead-acid, Lithium, both?

Battery On/Off switch does not need to be fused if it is capable of breaking the maximum current from the battery

The wires to bilge, electronics, lights are usually already made up and generally #16 or smaller with their own in line fuse

Use a single point ground and all the ground wires go to that point

If this is a house boat with 100 feet of wire run in every direction, your wire sizes are good, if it's a16 foot run about with all the stuff at arms length, its over kill with the 4, 6 gauge wires

Most important with this is a good quality fire extinguisher for marine use (proper restraint bracket and gauge) in easy to reach location .

I like the reply quoting from American Boat and Yacht Council

do not solder wires, crimp connections only, ring terminals, no flag, stab, fork, 3 way, screw pressure and everything copper rated no aluminum

use a spray coating on all your open connections like LPS3 or Fluid Film, do not allow anyone on your boat with WD-40

Starter/Deep Cycle battery

 

[CalicoJack]

I would say the first thing you should do is find out what size wire for the starter is required by Mercury.

#10 wire to your fused/breaker switch panel

I don't know what a combo battery is. Are you going lead-acid, Lithium, both?

Battery On/Off switch does not need to be fused if it is capable of breaking the maximum current from the battery

The wires to bilge, electronics, lights are usually already made up and generally #16 or smaller with their own in line fuse

Use a single point ground and all the ground wires go to that point

If this is a house boat with 100 feet of wire run in every direction, your wire sizes are good, if it's a16 foot run about with all the stuff at arms length, its over kill with the 4, 6 gauge wires

Most important with this is a good quality fire extinguisher for marine use (proper restraint bracket and gauge) in easy to reach location .

I like the reply quoting from American Boat and Yacht Council

do not solder wires, crimp connections only, ring terminals, no flag, stab, fork, 3 way, screw pressure and everything copper rated no aluminum

use a spray coating on all your open connections like LPS3 or Fluid Film, do not allow anyone on your boat with WD-40

I researched Mercury and it said they use 4awg on their outboards.

 

[CalicoJack]

How big is your battery capacity?? Do you spend a long time on the water running accessories ?? The reason I ask, is will you drain that battery after a day on the water so it won't start your motor ?? On all my boats that have had electric start motors, I use two batteries...one for starting the main motor only and the other battery for bilge pump and all electrical accessories In this way you always know your motor will start when time to head back in. Just some food for thought for ya !!

To be honest I haven't even used the boat yet. It is a work in progress.

 

[Still Afloat]

I’d loose the switch. It’s intended for dual batteries and not necessary for your installation. Instead wire the motor direct to the battery. Place a breaker (like CalicoJack posted) close to battery in fuse panel circuit. It will offer protection in case of a major short circuit and serve as a disconnect for accessories.

 

[Al U Minium]

I’d loose the switch. It’s intended for dual batteries and not necessary for your installation. Instead wire the motor direct to the battery. Place a breaker (like CalicoJack posted) close to battery in fuse panel circuit. It will offer protection in case of a major short circuit and serve as a disconnect for accessories.

Sorry, I have to disagree

The battery that has been selected has enough amperage to instantly turn wires into molten metal with hazardous gases that can choke the life out of a person

A good disconnect switch can break that high current without the switch failing

Get the ring terminals properly crimped with the ring size to fit the stud

The battery needs to be in a covered ventilated box securely strapped down

 

[Still Afloat]

Exactly my point, replace the switch with a breaker that doubles as a disconnect.

The disconnect and wire gauge from disconnect to fuse panel should be sized to support the fuse panel rated load. If done correctly there will never be a risk of burning the wires.

 

[airshot]

Not understanding the reason for crimped terminals, some even mentioned a no no for soldering... Always thought soldering would be better. Personally have had issues with crimped connections, so am I missing something or personal preference ??

 

[Al U Minium]

A crimp connector provides a pressure connection to the wire and the terminal

A soldered connection connects the wire to a terminal using eutectic metals of lead, tin, silver that are heated to the melting point and flowed into the wire and terminal. If the wire and/or the connector is not at the temperature to melt and flow the solder, the solder will not properly bond to the wire and/or the terminal. That creates a cold solder joint recognizable by a frosty appearance. A cold solder joint is an inefficient bond between the wire, solder, terminal.

I always found it easiest to explain by soldering 2/0 stranded wire into a battery terminal and cutting the connector in two. Did the same with 2/0 wire in a terminal properly crimped. When the sectioned pieces are examined, the soldered wire had obvious voids and many strands did not even get soldered. The crimped one look like a piece of copper rod and the wires strands could barely be identified.

Other ways for bonding dissimilar metals are exothermic bonding, laser fusion, high current discharge welding, among other methods.

One more point with soldering wires, the dissimilar metals in a damp environment promotes both corrosion and electrolysis which in time will severely degrade the connection.

I know this is out there for an explanation, but it should give you guidance to make good decisions based on science and not hear say.