Battery Cable AWG Size?

[drivadesl]

Happy Independance Day to America!! Have a safe and enjoyable day out on the water to all!

I seemed to have misplaced my Boat Wiring Guideline book, so here's my question: I am running power from a single battery mounted towards the bow, to a console where I will distrubute power via a fuse panel. Will also be tying power to the starter for my 15HP OB direct. Run will be roughly 10' to starter wiring connection. Any advise on what size cables I should use?

Thanks.

 

[Augoose]

Re: Battery Cable AWG Size?

If possible, I would try to add up the amperage pull from all the components you wish to add then use the chart below to see where your demand falls. I looked up a honda BF15 hp and it lists a 12 amp pull for the electric start and a 6 amp pull for the manual. Also, 10 feet is a LONG distance so you'll need to add a size or two just for the length. The link at the bottom will give you a lot of extra info. I would probably go with 10 gauge just to be sure.

Gauge 110V 12V
22 5A 5A
20 7.5A 8A
18 10A 10A
16 13A 20A
14 17A 40A
12 23A 60A
10 33A 100A
8 46A 150A
6 60A ??A
4 80A ??A
2 100A ??A
1 125A ??A
0 150A ??A

http://www.rowand.net/Shop/Tech/WireCapacityChart.htm

 

[seabob4]

Re: Battery Cable AWG Size?

You'll be fine with 4GA back to the motor, 10GA to feed the panel...

 

[drivadesl]

Re: Battery Cable AWG Size?

Thanks Guys. THe manual lists the starter maximum draw at 7.5A. Rest of load is battery minder, horn, running lights, fishfinder. I'm planning on a single deep cycle starting battery. Do you think that will be enough to run these (not at once of course) plus a 65lb electric trolling motor and still be charged by the motor charging circuit. Alternator is listed at 5A. Don't plan on trolling around all day on electric, mostly intermittant use. Didn't want to go with to batteries but ......

 

[H20Rat]

Re: Battery Cable AWG Size?

Thanks Guys. THe manual lists the starter maximum draw at 7.5A. Rest of load is battery minder, horn, running lights, fishfinder. I'm planning on a single deep cycle starting battery. Do you think that will be enough to run these (not at once of course) plus a 65lb electric trolling motor and still be charged by the motor charging circuit. Alternator is listed at 5A. Don't plan on trolling around all day on electric, mostly intermittant use. Didn't want to go with to batteries but ......

depends... can you pull start the outboard? If you can't for any reason, I'd go with dual batteries without a second thought. You don't need to worry about the 99% of the time the single battery is enough, you worry about the 1% when you accidently find a good fishing hole and run your trolling motor too much.

If you can pull start the 15hp, then a single should be fine.

 

[Stachi]

Re: Battery Cable AWG Size?

4 AGW wire will do fine for you .... search for a set of 20' 4AGW jumper cables ... I found a set a few years ago at Walmart,... they were under $25.00 , Cut the ends off , and save the ends for other use.

 

[drivadesl]

Re: Battery Cable AWG Size?

4 AGW wire will do fine for you .... search for a set of 20' 4AGW jumper cables ... I found a set a few years ago at Walmart,... they were under $25.00 , Cut the ends off , and save the ends for other use.

BRILLIANT!! BRILLIANT!!

And it does have a pull start so I was hoping I can get away with a single battery. I'll go with that set up for now, and see how it works out. I know what you mean about the 1% though.

Thanks for great input!

 

[hungupthespikes]

Re: Battery Cable AWG Size?

+1 on the pull start, one battery should be fine.
From what you have told us, 14 gauge Marine wire and a 30 amp fuse. You can up the fuse and/or wire if you like but 30a is more than your given needs.
Please don't use automotive or industrial wire or connectors. Use marine wire, stranded, tinned, and marine connectors, plated with heat shrink, they are less likely to corrode or swell from the water over time. Besides you only want to do this one time, not every other session or even 5-10+ years.
Use the right tools, material, and take the time to do it right, "put it to bed".

With only 5 amp alternator, a good charger with a battery maintainer would be a plus.

 

[NYBo]

Re: Battery Cable AWG Size?

Howdy, neighbor!

I've never heard of a trolling motor of that size that wasn't 24V, which means two batteries.

Where do you boat?

 

[heyyou325]

Re: Battery Cable AWG Size?

I am planning on doing something similar, but not quite exact. I'm installing a second marine deep cycle battery to run a 54 lb trolling motor that uses 50 amps. I want to put an isolator between batteries to make sure the one will start my main engine. It's an inboard 350 OMC. I was wondering if number 4 wire would be heavy enough to go from one battery to the isolator and than to the other battery. Your chart makes me think I could get away with 12 wire as the trolling motor is the only thing I want to run. But better safe than sorry, would 8 be big enough? That looks like the size going to the trolling motor. Oh, is it ok to use 2 different marine deep cycle batteries, one for cranking, and one for long life, with an isolator between them? I've been told it is as long as the isolator is there.

 

[hungupthespikes]

Re: Battery Cable AWG Size?

NYBo your absolutely right. Sorry drivades I didn't even consider the troller, thinking of it being direct wired with the battery already toward the bow.:facepalm:

 

[drivadesl]

Re: Battery Cable AWG Size?

My mistake on the motor size, its 55Lb thrust 12 V Minnekota, bow mount. Had that in place before recently getting the 15hp electric start, so since already mounted, and the fact I want to keep the weight forward, would use it as is.

I priced 4gage, 20' jumper cables (made in USA!) in Wallymart, they go for $38. I bought them and may consider using for power distribution. Looking at marine cable now, its pretty pricey, but good points on doing it right the first time.

Hey NYB! You in the neighborhood?? I have two boats, and usually take this one to Winding Hills or in the past monguap pond in Sullivan county. Favorite lake is Lake George, used to go on the hudson from Newburgh, but tired of the public ramp there.

I'm rigging it for a trip to a camp ground at Round Valley Reservoir in NJ. A friend of mine told about it, campsite is accesible by boat or foot only so going there in a couple weeks. Need to get my rig set up in time for then.

Thanks all for your input.

 

[NYBo]

Re: Battery Cable AWG Size?

Hey NYB! You in the neighborhood??

Yep. Beaver Dam Lake.

I have found the public ramp in Newburgh quite, er, entertaining.