Seeking Advice on Common Configurations

[GordMay]

Welding cable ma be cheaper than tinned marine (BC-5W2) cable, but I don't recommend it.

[hellosailor]

Sean, no question that welding cable is cheaper but it is also the wrong cable. Welding cable is designed for use with AC, which travels on the skin of a conductor. So it has many fine strands to present the maximum surface area for AC use.

DC battery cable, or Type 3 Machine Wire (which is virtually identical), has thicker strands to conduct DC power. DC travels in each strand, not just on the surface. So the thicker strands give you less resistance, and are less likely to be eaten out by corrosion. Welding cable is also typically not fully tinned--so the creeping rot really can get into it on boats!

And, the insulation on welding cable will probably be different, i.e. it may not have the oil/heat resistance that the others have for engine spaces. Of course, if the budget is really tight,you buy a Zen Windlass.

Zen Windlass? Sure. Imagine the windlass is raising the anchor rode. See it in your mind. Will the rode to store and coil.<G>

[Alan Wheeler]

As long as the ends are sealed, plain copper welding cable is jut fine.
Terminate the end connector via the means it is designed for. (That maybe crimp or solder, which ever, I am not arguing that point in this context)
Slide a piece of glue/heatshrink over the joint and lug base. Heat until glue oozes out. It will remain totaly sealed. If you don't have pre-glued heatshrink, it can be done just as easily with a hot glue stick applied before you shrink down the heatshrink. You can get carried away by all sorts of applications of "Dr Magical" cures, but I have found this to be easy and so far fool proof. I have had a good test on one application of this technique on an Anode mouse I have over the side of the boat. It has been two years now of permanent emersion at 5ft down. The anode bolted to the lug gets replaced about every 6months.
I did exactly above, then placed a small smear of Lanocote over the above and then another piece of ordinary heatsrink over the top again. So far no water has crept up under the seal and migrated into the cable.
I also have cables run for my wich that I terminated in this way nearly two years ago. I recently added a maxwell anchor solinoid pack and had to re-terminate some cables. I had lovely clean copper underneath.
so I think ordinary copper can be used, as long as it is sealed well.

[hellosailor]

Alan-
Sealed is good. The heat-shrink trick will work well if the cable lug (the terminal) is a "cup" type, rather than the cheaper open type sometimes found. I paint terminals with a couple of coats of Liquid Lectric to get the same result, and pot down the entire connection that way when appropriate. Clean and shiny is good...I just figure if the cable isn't tinned, and somehow it gets cut, scraped, perforated (even in shipping or a pinhole from manufacturing) I'd rather not find out about that. I'll work with spit and chewing gum when I have to, but given the choice...<G>...

[S/V Elusive]

I seem to be an 'aside' tonight - also to be found at a welding shop: Nice big rolls of stainless wire that is great for seizing your tackle - and VERY inexpensive!

[ssullivan]

Adding to what Wheels said... welding cable (1/0) is the ORIGINAL battery cabling used on my boat. The copper inside the cable that I recently cut to reconfigure my batts was shiny as new. It's *not* sealed at the ends in any way and is it's 20 years old.

I think a lot of what people say on here is great when designing the "ultimate wish boat", when you have a million dollar budget, but realistically:

If a cable can look/function as brand new 20 years into service, why waste valuable crusing funds on something that's overkill?

[hellosailor]

Sean-
I'm not sure about waste and overkill. I haven't found any good direct comparions between battery cable & welding cable, maybe Rick would be able to locate them.
What I am seeing are numbers (from varisou sources so ymmv) like a sustained ampacity of 190 amps for 4AWG battery cable, designed as 133/25 (strands/conductors) versus 1035/44 for the welding cable (yes, those were the numbers) and indications it is good for perhaps 100 Amps at a 1/3 duty cycle, since welding equipment is either AC or pulsed DC. So, the welding cable may actually have a sustained capacity of 1/3-1/2 the battery cable, making it less of a bargain.

Now, if you are just sizing the cable to take the starter surge, the charging capacity is so much less that may not matter. What I haven't found, and will matter, is the DC resistance of the cables. Using welding cable may be cheating you of voltage at the batteries. Or costing you fuel, as the alternator puts out higher voltage to overcome the loss. Or simply being cheaper--but needing a more expensive size to compensate.
There's no question it can be made to work. I just keep finding that shortcuts often are simply "cuts" in the long run.
I'd be delighted to see some real numbers on this!

[ssullivan]

Hellosailor - What you say makes a lot of sense. I'd like to see the real numbers too. Often, I simply oversize my cables a step or two above whatever the required rating in order to get less and less resistance. I also keep my runs as short as humanly possible. I have no electric windlass (manual windlass), so all cabling runs are quite short, with the longest at maybe 8 feet. I suppose if there were greater distances to cover, this would become more of a problem.

Incidentally, all of our DC power for lighting, etc... is tinned.

I am curious to hear Rick's take on this as well. I know his tinned vs. regular copper preference for normal wiring. I'm definitely curious.

[hellosailor]

Sean, a couple of summers ago a splice in (aren't they always) an inaccessible and unsuspected location failed. Or rather, the splice was fine, but someone had done a twist-n-tape and the untinned copper was BLACK and simply not conducting anymore. Black copper, green copper...I've just decided life is too short, tinned wire is cheaper than the hour wasted chasing one wiring problem.

It helps that last time I needed cable, I was able to buy a spool end of it.<G> Even with UPS, a fraction of the retail cost. If you need 50' of #4AWG tinned Type 3 Machine Wire...make me an offer, I can deliver on LI if it also includes sailing time!<G>

[ssullivan]

Thanks for the offer, but the boat's done!