Simple Single Outboard Wiring (SR5.4)

[ncp]

Lot's of info and questions posed all over the net as to how to do complicated wiring (1 engine/2 or 3 batteries, 2 engines/2 batteries, 2 or more engines/many batteries) but I couldn't find a simple diagram for one engine and one battery.

-Simple Perko On/Off
-Yamaha 90 Two Stroke
-Light loads - Only VHF, GPS and LED Nav
-The run from battery to engine is 13 ft. exactly (battery under console)
-The run from positive stud to switch panel is less than 18 inches
-Assume that the Blue Seas switch panel shown contains individual circuit breakers for each load
-There is no bilge pump - no need to wire anything directly to battery

1. What's the simplest, most cost effective way to do this?

2. What gauge wire for the runs that I have marked "Thick"?

3. What size master fuse/breaker do I need?

[Chris]

Originally Posted by ncp

Lot's of info and questions posed all over the net as to how to do complicated wiring (1 engine/2 or 3 batteries, 2 engines/2 batteries, 2 or more engines/many batteries) but I couldn't find a simple diagram for one engine and one battery.

-Simple Perko On/Off
-Yamaha 90 Two Stroke
-Light loads - Only VHF, GPS and LED Nav
-The run from battery to engine is 13 ft. exactly (battery under console)
-The run from positive stud to switch panel is less than 18 inches
-Assume that the Blue Seas switch panel shown contains individual circuit breakers for each load
-There is no bilge pump - no need to wire anything directly to battery

1. What's the simplest, most cost effective way to do this?

2. What gauge wire for the runs that I have marked "Thick"?

3. What size master fuse/breaker do I need?

- Correct size Battery cable from negative on Battery to Yamaha (no joins)

- Correct Size Battery cable from Battery to Isolator then on to Yamaha (no joins)

- Some reasonably thick wire from the battery to the switch Panel (8 or 10 AWG) ( I would normally fuse this at the battery end with a fuse suitable to cover all the appliances you have assuming they are all on at the same time

The VHF should really go directly to the battery and I would not run it via the switch panel, if it all goes tits up the idea being the VHF will be working even if nothing else does.

Main thing is to make sure all your cables are the correct size / rating for the items they are connected to and that the fuses or breakers in the switch panel are suitable for the items you are connecting up.

[Bigtalljv]

Do you circuit protect the engine positive? I didn't think so? Engine positive to big switch. Distribution panel positive to circuit breaker to big switch. Engine ground to battery, grounding block to battery. My Suzuki manual says for a suzuki 90 you can 4awg to 3 meters, 2awg to 4.7m.

It's been a year, I forgot everything I learned to wire my boat.

Jason

[ncp]

Originally Posted by Chris

- Correct size Battery cable from negative on Battery to Yamaha (no joins)

Originally Posted by Bigtalljv

Engine ground to battery, grounding block to battery.

Easy. So, you would attach two cables to negative stud on battery? One from engine and smaller one from neg bus bar?

Originally Posted by Chris

- Correct Size Battery cable from Battery to Isolator then on to Yamaha (no joins)

Originally Posted by Bigtalljv

Do you circuit protect the engine positive? I didn't think so? Engine positive to big switch.

What about circuit protection? None on the run from the on/off to the engine itself????

Originally Posted by Chris

- Some reasonably thick wire from the battery to the switch Panel (8 or 10 AWG) ( I would normally fuse this at the battery end with a fuse suitable to cover all the appliances you have assuming they are all on at the same time

Ok, so a 30A is probably ok just before the switch panel.

Originally Posted by Chris

The VHF should really go directly to the battery and I would not run it via the switch panel, if it all goes tits up the idea being the VHF will be working even if nothing else does.

Ok, I've heard that before on rib.net but think that it's less prevalent over here (don't know why - probably the same as Americans and life jackets)

[ncp]

Originally Posted by Bigtalljv

My Suzuki manual says for a suzuki 90 you can 4awg to 3 meters, 2awg to 4.7m.

Ok, it's $1.33/ft difference between the 4awg and the 2 awg - ~$35. If there's any question, I'll upsize!

[Bigtalljv]

Genuinedealz.com. They sell all the marine cabling bits you could need and make custom cables. Great prices and great service.

Marine batteries usually have the big lug and a smaller bolt so you have two attachment points.

I think you can circuit protect anything you want but I don't believe that you usually have a breaker between battery and switch. Usually it's a short run of big cable. Not much chance of a short there but that's for you to decide. Adds complexity and expense for big breakers.

My old boat didn't even have a big red switch. Accessories ran on a crappy fuse block without issue for 10 years. Dealer installed wiring....

Jason

[Bigtalljv]

I ran my ground, engine and batteries, to a large common grounding block. The breaker panels are fed with 10awg wire, 100amp breakers before that. Remember you are protecting the wire not the electronics for most part.

Wiring is an art, I am not an artist. Ended up with crossed wires . Looks ugly.

[ncp]

Originally Posted by Bigtalljv

Genuinedealz.com. They sell all the marine cabling bits you could need and make custom cables. Great prices and great service.

Exactly where I was quoting prices from!

[ncp]

Ok, since my last post I've taken the advice and re-drawn things.

-substituted BEP on/off switch and switch panel - cheaper. I can't say that I think any less of the quality of Marinco/BEP versus Blue Sea Systems.
-30A blade type fuse is the most cost effective here before the switch panel - especially since I've read that I don't actually need circuit protection at <40" and if in a conduit.
-removed the studs since you guys have said that the run to the engine needs to be as direct as possible and it's ok having two terminals to each battery post.

[Bigtalljv]

Looks good but I'm not the expert. Unless budget is a serious issue is use a breaker instead of the blade fuse. Make life simpler as its one less spare to have around.

Jason

[ncp]

Originally Posted by Bigtalljv

Looks good but I'm not the expert. Unless budget is a serious issue is use a breaker instead of the blade fuse. Make life simpler as its one less spare to have around.

Jason

Agreed - My Willard doesn't have a single fuse (all circuit breakers).

But, I'll have to carry fuses no matter what. Both of the switch panels that I looked at (Blue Seas and BEP) had integrated blade type fuse holders. So, I'd need them anyways.

If I do choose to go with a master circuit breaker for the 12v DC panel, it will probably be a Cooper Bussman 185/187 in 30A (The Series 187 Marine Rated Circuit Breaker features a manual reset with switchable function and is single pole thermal type.).

[Chris]

Originally Posted by ncp

Ok, since my last post I've taken the advice and re-drawn things.

-substituted BEP on/off switch and switch panel - cheaper. I can't say that I think any less of the quality of Marinco/BEP versus Blue Sea Systems.
-30A blade type fuse is the most cost effective here before the switch panel - especially since I've read that I don't actually need circuit protection at <40" and if in a conduit.
-removed the studs since you guys have said that the run to the engine needs to be as direct as possible and it's ok having two terminals to each battery post.

Looks fine to me, I always over spec the supply to the fuse / switch panel as you never know what you might want to fit in the future. For example a 12V outlet to run a hi power search light or an inflation pump for a small tender, these can draw up to 25AMPs, however if you don't see this being a requirement then the 30amp inline with 10AWG will be fine.

[Nightfisher]

FYI: Primary run between engine and battery is too long. Unlike AC Current, DC Current rapidly loses current on long-runs between battery and starter solenoid, and if the outboard utilizes a battery charging circuit, that length of run "13 feet" you will also lose an Amp or Two when the engine's trying to send low DC current to the battery to recharge.

[boristhebold]

Originally Posted by Bigtalljv

I ran my ground, engine and batteries, to a large common grounding block. The breaker panels are fed with 10awg wire, 100amp breakers before that. Remember you are protecting the wire not the electronics for most part.

Wiring is an art, I am not an artist. Ended up with crossed wires . Looks ugly.

Attachment 103189

That doesn't look ugly, looks damn neat compared to a lot of wiring. I redid mine last year and made improvements but still not happy with it all. I have a NMEA 0183 set-up, I will probably go NMEA2000 or Ray marine Sea TAlk next year.