Cable size for 3 pair 6V batteries ??

[Frankly]

Keep in mind that your analysis about things dividing equally might not always work out in the real world. Each of the 3 sets of batteries on Cbreeze is individually switched so potentially all the current draw could be from one set of the batteries. Even if the sets are not switched a connection/ cell might fail and the remaining two sets might pick up the load.

Over the years I have sometimes experienced some issues with the threaded studs side of the battery terminal connections (high resistance connection). For that reason I stick to the old lead battery post clamp but use a high quality plated copper terminal. I am probably in the minority on this but might keep this in mind if you are starting from scratch on the cables. Being a little anal on the electrical system has served my well over the years.

Frank

[rgesner]

How about for 4 pair?
I'm replacing my 6 (3 pair) of Trojan T-105s with 8 new one (4 pair)

Is 1/0 or 2/0 sufficient and should my existing cables be reusable, or do 4 pair require larger interconnects than 3 pair?

[mitiempo]

Originally Posted by donradcliffe

The thinner the individual strands in the cable, the faster they turn to dust when moisture wicks in. Stay away from the S/o stuff on boats.

Each strand of boat cable (Ancor or similar) is tinned and will not corrode easily. Each properly crimped lug should be covered in adhesive heat shrink. The wire will not corrode if this is done. This is the only type of wire that should be used on a boat.

[redsky49]

Quote:
Originally Posted by donradcliffe
The thinner the individual strands in the cable, the faster they turn to dust when moisture wicks in. Stay away from the S/o stuff on boats.

Each strand of boat cable (Ancor or similar) is tinned and will not corrode easily. Each properly crimped lug should be covered in adhesive heat shrink. The wire will not corrode if this is done. This is the only type of wire that should be used on a boat.

Actually, donradcliffe makes a good point. In some electrical cabling the individual strands are quite small, even described as fine. While I am not aware of the manufacturing schedules of the better vendors, it seems that as cable size increases, so does the diameter of the individual strands. In the wire sizes we are discussing for battery connections though, I doubt that you will encounter any truly fine strands.

My experience is that some of the larger cables such as 00 and larger often use the minimum number of strands to reduce manufacturing costs. A good example is inexpensive jumper cables. Here you are likely to have as few as a dozen or less individual strands. Another example is welding cable, which is frequently found (improperly) used in larger battery systems. A good cable choice, in my opinion, is known as railroad cable. This is readily available in larger sizes, 00 and up, and has better flexibility, as well as being tinned, and seems to have a thicker insulation.

To slow down the inevitable internal corrosion of any stranded cable, even tinned cable, I have found that it is vital to keep the outside atmosphere from entering the cable. Heat shrink tubing being the first line of defense.

In addition, for greater security I try to employ closed terminals (often larger terminals used for battery hook up are open at the end, allowing the entrance of moist, salty air).

For my final bit of protection I use an "electrical joint compound" to prevent any oxidation at the terminal. The product I have on hand at the moment is made by Burndy Products, Penetrox E. A very thin coating of exposed bare wire or terminal connection will protect against copper corrosion indefinitely. It also works well as an anti-seize.

Using all the best products and methods should ensure that cables should remain corrosion free for an extended period.

[donradcliffe]

[QUOTE=mitiempo;1992519 The wire will not corrode if this is done..[/QUOTE]

The correct terminology is 'the wire will not corrode as quickly if this is done".

I agree that the tinned ancor wire has about the right strand thickness (thinner corrodes faster, thicker breaks from vibration), but I have often had to redo some quite well prepared wiring in the marine environment.

[model 10]

[QUOTE=donradcliffe;1992756]The correct terminology is 'the wire will not corrode as quickly if this is done".

I bought a bunch of surplus wire a the Boeing Surplus Store in Seattle when it was still open. Everything was sold by the pound regardless of what kind of wire it was. I got a partial reel of a silicone jacketed space ship wire. The conductor is silver colored, has very small strands and it doesn't seem to corrode. It also takes a blow torch to melt or burn off the insulation, great for re-entry to the anchorage on fire.

[mitiempo]

Originally Posted by donradcliffe

The correct terminology is 'the wire will not corrode as quickly if this is done".

I agree that the tinned ancor wire has about the right strand thickness (thinner corrodes faster, thicker breaks from vibration), but I have often had to redo some quite well prepared wiring in the marine environment.

Using the correct tinned 105 degree boat cable and closed lugs with adhesive heat shrink the wire will not corrode. I have being doing this for years and have not seen corrosion on a properly made cable. The badly done cables - a different result.

Here is a very good how-to: Making Your Own Battery Cables Photo Gallery by Compass Marine How To at pbase.com