The Stovebolt Site Forums The Shop Area The Electrical Bay 4/0 battery cables? Bah Humbug!

I would disagree with whoever wrote the article about battery cables. Has anyone looked at wire gauge charts to see how thin 4 gauge is. I just got through measuring a NOS Delco battery cable. It measures .325 which is 1/0 gauge. Any engine that spins on 6 volts with a 4 gauge cable must have very little compression.

Well we've been thru this one a hundred times before, but it seem to keep coming full circle. I’ll just have to voice my opinion again on this cable thing.
Ken, I think you’re right about #4 being recommended for a 6v starting system. That should be reviewed and possibly corrected.
You could actually start your Chevy inliner on 6v using a 14 ga. wire IF, that is IF it started on the first turn over and didn't draw current for more then a second of two. The load carrying ability of the wire is determined by its ability to dissipate the heat generated by the current flow. Almost any size copper wire in a four or five foot length has very little resistance. For instance an AWG 4/0 wire five feet long would have only .000245 W resistance to current flow. Your house wiring generally an AWG 14 wire, five feet long would have only .012625 W resistance. As Jerry so correctly pointed out, there are several things that determine a cables load carrying characteristics. Fine stranded better than course, in free air or in a bundle. Length of the cable enteres into the formula with voltage drop.

The kicker comes in when the wire heats up, as the temperature of the copper increases so does the resistance. This has a very rapid snowball effect and that’s why you burn up a light gauge wire or why a #4 cable will heat up if you crank for a long time. A number #4 cable is perfectly capable of starting a well tuned Chevy inliner in sound mechanical condition but it’s meant for a 12v system. If you have to crank than engine for 20 or 30 seconds to get it started, the cable will heat up and as it heats up the risistance goes up, and then there is more voltage dropped across the wire so after 30 seconds of cranking, sure, your starter is going to be sagging pretty bad. I believe the proper factory supplied cable size for a 6v system would have been a #2, many of the heavy duty after market replacement cables were a #1 or 1/0.

But now that you have that 4/0 cable installed, you can skip that engine rebuild and leave that low compression the way it is, who needs a ring job. And why bother with a valve job or that Spring tune up, that old reliable six banger will probably run just fine with those burned valves, coroded connections once you get it fired up. So with a good strong 8v battery in place and 4/0 welding cable connecting it to your starter, you’ve got plenty of cranking power to get you thru the summer, if you don’t burn up the starter first.

Or you could rebuild, clean up and tune up and get by just fine with what the truck came from the factory with 50 or 60 years ago.
Denny Graham
Sandwich, IL

The cable I measured the conductor on was a Delco/GMC OEM to fit a 1/2 to 2 ton and the conductor is 1/0 gauge. Possibly Chev used a lighter cable. After running 855 cu in Diesels for 45 years, I have learned to keep my terminals clean. Its an expensive ordeal calling road service when one won't start a thousand miles from home.

As I said in another post, they were one gauge, at least in my era of vehicles.
Click here to see.

Thanks for finding that Jon. Electrical theory was well established by that time so I'm sure it wouldn't have changed as time went on. Documentation in Chevrolet Service Topics is good enough for me.
Denny Graham
Sandwich, IL