Battery cable size gauge Options

[Harpo]

What size/gauge wire do I need for battery cables? My current one is .35 inch in diameter including the insulation.

http://www.allenelectric.com/referencedata...rence_chart.htm

This page suggests I need size 0. That seems rather large

Thanks

David

[Dave_Darling]

Mo biggah mo bettah.

Seriously, you want a large cable, because the starter draws a really ferocious amount of current. You also want sizeable ground cables.

--DD

[Drums66]

.....I second these comments! (IMG:style_emoticons/default/idea.gif)
(IMG:style_emoticons/default/bye1.gif) (IMG:style_emoticons/default/wolfgang.gif) (IMG:style_emoticons/default/robot.gif)(stronger)

[Cap'n Krusty]

The ground cable should be larger than the positive cable.

The Cap'n

[Harpo]

Thanks everyone

[Retread]

[When doing a major engine out project on customer's cars I replace the stock cable to the starter with a 1 GA 60 inch cable. These are available from NAPA but will likely have to be ordered. Usually takes a day or two to get it.

I prefer the flat, braided heaviest ground cable NAPA sells i a 9 inch length.

Please remember to clean the metal around the ground stud to ensure an excellent connection.

These two components almost eliminate the need for the hot start relay kit.

FWIW, cables need lots of strands. Most current is carried on the outer surface of a strand of wire. More strands = more surface area = less resistance.

[stugray]

Most current is carried on the outer surface of a strand of wire.

That is not true except for high frequency AC current.

Solid wire would be much better in our cars, except stranded wire has better fatigue properties and is flexible.

For my whole harness rebuild I used:
4Ga on -
battery + to starter
battery - to chassis
battery to the front fuse panel.

10Ga from Alt to Battery (or to starter if you dont have a cutoff switch).

And I have much longer runs because my battery goes through a master kill switch.

I tried to use some of the tables that specify wire gauge vs rated current, and the wires were MUCH larger than the stock Porsche wiring harness.

You have to take into account - Is the current intermittent (Starter) or continuous (headlights).
If continuous, then the rating tables are closer, but: "what gauge is the wire that carries the current to the starter solenoid in the stock harness?"

If you figure that out you will see that the Porsche engineers didnt use those tables either.....

Stu