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Battery Cable Color (?)

Jun 29, 2010
993
Beneteau First 235 Lake Minnetonka, MN
After moving my battery to the other side of the boat I realized I have now undersized the cable. Mind you, I do not use battery all that much as I mainly race during the daylight and do not as of yet have instrumentation installed. I read some info in a previous post that I should be using yellow instead of black, especially as I am planning on doing a shore power install eventually. I have one group 27 battery, no starter as I have an out board, before I spend $$ on 0 gauge wire and lugs, should I buy red and black or red and yellow for my installation?
 
May 24, 2004
5,884
CC 30 South Florida
What do you use the battery for? I have used 6 gauge wire from battery to panel and circuits buzz to power the navigation lights and a bilge pump on a 21' boat. It is all in the roundtrip run and the loads.
 
Jun 29, 2010
993
Beneteau First 235 Lake Minnetonka, MN
What do you use the battery for? I have used 6 gauge wire from battery to panel and circuits buzz to power the navigation lights and a bilge pump on a 21' boat. It is all in the roundtrip run and the loads.
It will be used for Running Lights, Anchor Light, Steaming Light, Interior Lights, Instrumentation (i50/i60), Stereo, etc.... Its not the size that I want to know about, I know I need 1/0. I am wondering if I am good with Red & Black or should go to Red & Yellow due to me adding shore power.
 
Jan 4, 2006
2,517
Hunter H-310 West Vancouver, B.C.
As far as yellow goes, "my opinion" would be to keep it simple and keep your DC (-) black. Personally, I still connect yellow with AC wiring power supply.

Are you sure you're actually looking at 0 gauge wire for your DC wiring ? Don't know what your heaviest DC load and length would be but maybe time to haul out a voltage drop chart such as below. For an inboard, your starter would be your heaviest load and you say, you don't have one with your outboard.

Also check out Genuinedealz for wiring costs.

 

Attachments

Oct 29, 2016
1,397
Hunter 41 DS Port Huron
ABYC Wire Color Code, Yes Yellow for ground, when I wired my new batteries I could not find 2/0 Yellow so I did them in Black with yellow banding on the ends
Marine Wire Colors.JPG
 
Jan 11, 2014
4,155
Sabre 362 113 Fair Haven, NY
It's fielders choice. The current ABYC standards call for Yellow DC ground so as not to be confused with Black AC Hot. I would be consistent with the current wiring in the boat. Any AC lines you install will be triplex which is hard to confuse with a 1/0 battery cable of any color.

As others have said, 1/0 cable seems bigger than necessary. No sense in carrying the extra weight if you don't need it.
 
Jan 4, 2006
2,517
Hunter H-310 West Vancouver, B.C.
I know I need 1/0.
Now I know you need to do some calculations for your wiring. The DC wiring from my batteries goes to a starter around 180A and a 90A windlass and many other loads all at #2 wiring.

Send us your lengths and loads, and I'm sure we can work out some much more inexpensive wiring by calculation. Also, running 1/0 wire into a battery box is a real bear.
 
Jun 29, 2010
993
Beneteau First 235 Lake Minnetonka, MN
OK, so I have had the color chart for some time now, thanks. From the recommendation in the documentation for my Blue Sea panel it is stated to use 100 amp as the total load. I have a round trip of 30 feet, 15 feet in each direction. I moved the battery to the other side of the boat. You know us racers, more even weight distribution. That gives you 3000 Famps, according to their chart, for 3% voltage drop, size 1 is 2803 Famps and size 0 is 3536 Famps.

This is where I am getting the sizing from. If I can "get away with" smaller wire, well hot damn, I am all in for that. I have already decided I am going yellow and red now because, reasons.
 

Maine Sail

Moderator
Feb 6, 1998
11,037
Canadian Sailcraft 36T Casco Bay, ME
The ABYC does not spcify that yellow must be used it is Black OR Yellow for DC negative. In a new build, or complete rewire, yellow would be preferable but with an older boat you can just stick with black and go a step further and put yellow heat shrink at the terminal ends or, as should be done anyway, clearly label the wires.

If you boat is already using black, just stick with it and clearly label it. If you get to start from scratch, and most owners here don't, then by all mean use yellow for DC negative.

If this bank could ever be called upon to start the engine, 1/2/B switch or emergency parallel, or to power a large inverter, then you will need large gauge wire in order to properly fuse it to handle the cranking currents and not nuisance trip. This is why builders today pretty much use 1/0 or larger battery cable even on small sailboat aux engines.

 
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Oct 29, 2016
1,397
Hunter 41 DS Port Huron
I have to ask, what is your actual load summation?, What is the capacity of the charger you are using?
 
Jan 11, 2014
4,155
Sabre 362 113 Fair Haven, NY
This is where I am getting the sizing from. If I can "get away with" smaller wire, well hot damn, I am all in for that. I have already decided I am going yellow and red now because, reasons.
When you calculate the total current draw, remember not all devices will be on at once. If sailing at night, the running lights will be on, but not the steaming or anchor light. Instruments draw next to no current, maybe 1 amp. A stereo will only draw a couple of amps. The main breaker on Second Star's DC panel is a measly 50 amps and even with the refrigerator running, MFD, Radar, Autopilot, DWS instruments, AIS and VHF, I haven't blown the breaker yet. And my refrigerator draws about 30 amps.

The Blue Seas recommendation is probably for the maximum the panel can handle. If you fuse at the battery for a smaller cable you will be fine. 50 or 60 amps will probably be adequate for your needs. The Blue Sea Circuit Wizard says 50 amps at 30 feet is 3 AWG (good luck finding that size cable!), go up a size to 2 gauge with a 50 amp battery terminal fuse.
 
Jan 4, 2006
2,517
Hunter H-310 West Vancouver, B.C.
That gives you 3000 Famps, according to their chart, for 3% voltage drop, size 1 is 2803 Famps and size 0 is 3536 Famps.
Famps ? ? ? Too complex for me and way above my pay grade.

Why not look at how many amps (A) will produce a 0.36V drop (3% allowable) in a 30' long, 1/0 wire ? Let's say to and from your (+) and (-) busses in your electrical box. And it's all downhill from there.

The resistance of the 30' wire will be (30/1000) X 0.102 = 0.003 ohms

Ohms laws states that:

I = E/R

where E = 0.36V (the allowable voltage drop) and R = 0.003 ohms

therefore

I = 0.36/0.003 = 120A

Pretty heavy for most people I travel with.
 
Feb 5, 2004
3,933
Tartan 3800 Westport, MA
I confess this is the very first time I have seen the units "Famps." I had to google it - found a Blue Sea Systems page that defines it as Feet x Amps. Maybe BSS made this up?

The 1/0 sounds like overkill.
 
May 24, 2004
5,884
CC 30 South Florida
Famps ? ? ? Too complex for me and way above my pay grade.

Why not look at how many amps (A) will produce a 0.36V drop (3% allowable) in a 30' long, 1/0 wire ? Let's say to and from your (+) and (-) busses in your electrical box. And it's all dow…......………………….
It is not the gauge, it's the color.
 
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Jun 29, 2010
993
Beneteau First 235 Lake Minnetonka, MN
I have made a decision and re-sized things more realistically and for my loads. Thank you all for your comments, even if they had nothing to do with the question. ;)