Make Your Own Inexpensive Battery Cable

Some would say “old fashioned,” some “stupid,” and some “why?” Say what you will, I’m going to run six volts in my ’33 Plymouth coupe project.

So, I was looking for an inexpensive, (read “cheap,” ) way to wire the battery from under the driver’s seat to the starter motor and ground, a total run of about six feet. A friend offered me some 1 aught welding cable he had laying around. This stuff is very flexible, yet plenty adequate for a six volt system, and the best part, free!

The local Batteries Plus has a good selection of ends, including their compression type fittings. Although the total cost was $44 bucks, they were the most expensive part of the project, the rest of the cost being heat shrink tubing from Harbor Freight. This was for two battery post ends, and four 3/8” eyelet ends. Installation is very simple.

Here is the wire prior to stripping.



And here is one of the ends to be attached.



First, the wire insulation is stripped, leaving enough for the compression nut to fit over the bare wire, plus some to go inside the terminal.



When sliding the compression nut onto the bared wire, bulb grease, (silicone,) is your friend. (Gloves help, too, as an occasional stray copper strand will get angry and jab you.)



The silicone will also help the terminal to slide over the wire and begin to engage the threads. A 9/16” wrench fits the compression nut, and any screwdriver shaft will turn the terminal to tighten. Be sure, when tightening, to turn the terminal, not the compression nut. This will prevent twisting the cable.



Finish up with a sleeve of heat shrinkable tubing.



Here is a shot of another end assembled and ready to install on the battery.



Ready made cable is available in a gaggle of lengths for 12 volt at all the auto parts suppliers. Six volt cable, not so much. Making these cables was a simple fix that reflects the basic idea of this car; that being its attempt to recreate a simpler time.

 

Why not solder the ends on. Its a whole lot cheaper than $44 for those goofy compression fittings.

 

Solder is .04 to your 44.00 connectors. Its a better sealed and mechanical connection as well.

 

I've used the compression terminals, and they work great. They are re-useable as well.

 

and silicone may be your friend but dielectric grease is your enemy. It is an insulator against electrical conduction. At best it will only cause a minor rise in resistance/ heat in your cables. White lithium would be a much better choice in this situation.

 

inexpensive? this seems VERY expensive.

 

Nice clean install, but I'm going to have to agree with the other guys here. I solder my connections like that. The copper end costs like $2 and some solder I have laying around, and it takes like a second to do.

I just strip my welding cable, put my copper end in a vice and heat it up with a propane torch. Then I insert the solder in the copper end until it melts, then stick the welding cable into the pool and let it cool. Knock off any excess solder and apply heat shrink. done.

 

X2.

Buying welding cable is cheaper and better than some kits out there.

 

If you're sticking cold welding cable into the pool of melted solder, you're not getting an ideal connection. Both the cable and the terminal should be heated, then let the solder flow into the connection.

 

Good point, that's why I don't have excess solder oozing out.

 

great for trunk mounted Batts

 

works for me.. i used to sell welding ( and gas products etc). I sold quite bit of arc welding cable.. --our sizes here were 35mm and 50mm sizes were for 150amp or 250 amp machines respectively -- for battery cables.

and proved great cranking even over that distance due to thickness of the cable...

the metric size of the cable i have given is 3.1 times the diameter of the copper core ie 35mm around 1cm or about 3/8th 50mm = about 1/2 inch i cant however explain the whyfor of the sizeing

make your own length ,, for example 6meters(yards) with crimp on connectors for around $30 NZD,, off the roll it proved popular and much cheaper option than an auto electricians alternative ...

 

I've heard good things about using the battery cables from BMW E30's (battery in the trunk in some of them) if you want a trunk mounted battery or just high quality copper cable to use in a project. Has anyone here done this?

 

there is an art (however inconspicuous) to sweating a lug to a cable... heating the lug, pooling the solder in it is what to do, however, you need to kep the heat on when dunking the cable in. Too little heat, and you have a cold joint (higher resistance) too much heat and you get capilliary action (solder runs up the cable making the 1st 2 inches solid not flexible)
Most cables I did (hundreds) had a little insulation melt, but a good join. Bets way to hide the melt is tape the end of the cable when done (a lot) then put the shrink on top. The world will never know......

 

How is dielectric grease bad for the connections?

 

Yeah? Isn't dielectric grease supposed to allow current, but keep corrosion away? I understand you will need to have contact of the strands to the lug, but the grease won't prevent current flow, will it? I always install the grease on terminals and bulbs (if I have some handy), and they never seem to fail to work.

 

wonder if using an old set of good quality jumper cables (with the proper ends attached)would provide a decent gauge cable to use??

 

if you call this cheap, check out a tractor/farm supply store that makes cables for tractors. they have better cable than welding cable and they crimp the ends on. FAR better cable for about the same price

 

i ran that set up for years! I always had issues with the trunk mount bat. i put on a better set of cables, all my problems gone. even my hot start issue

 

What he said ?

 

"dielectric" means it's an insulator, not a conductor. So, no, it doesn't conduct electricity.

Also, I'm a fan of soldering, (every single connection on the new harness in my F1 is crimped then soldered), but soldering alone is not a "mechanical" connection. It's more like a "glued" connection, for lack of a better term. Trust me, I had a college professor go on and on about this..... solder alone isn't very strong in tension or shear. The best type of solder joint you can build is by doing a true mechanical connection first, such as looping the wire through a hole in a connector, then twisting it tight, then soldering. That's not real feasible in this case of course.... so I believe a crimp connection would be strongest.

In a nutshell, use solder to create the electrical connection, NOT the mechanical connection.

Sorry for the sidebar. Great looking cables you built there!

 

Thanks for a different way of looking at this!

 

OK, I work in the electronics (semiconductor) industry and I am adding my $.02. It's only 2 cents, so take it for what it's worth.

'Dielectric' is often used in a general sense to refer to a material (such as ceramic, mica, plastic or paper) which is a poor conductor of electricity.

This term is used in the classical description of a capacitor -- two electric conductors separated by a dielectric. By applying electric charge to one conductor an electric field is created. The dielectric allows the electric field to pass through it and affect the other conductors; however the dielectric prevents electrons from flowing between the conductors, so the electric field remains (and the charge remains stored on the conductor).

[Side note for beginners: An electric field creates a force (measured in Volts) upon an electron or charged particle which tends to make it move. The conductor allows electrons to move easily within it. The dielectric resists the movement of electrons in it.]

More generally, we speak of a 'Dielectric Field' as a mathematic description of how electric charge influences the properties of the space around it. The Dielectric field interacts with space and with any material in the space to create an 'Electric Field'.

In simple terms, the electric field at any point is the product of the dielectric field at that point and the 'Dielectric Constant' of the material at that point. In more general terms, the 'electric field vector' at a point is the tensor product of the 'dielectric field vector' and the 'dielectric tensor' of the material at that point.

That being said, I would have made the connection dry. Otherwise, I would have done it exactly the same way. Simple conclusions from early electric pioneers like Faraday and Franklin determined long ago that electrons travel along the surface of a wire and not through it. That being said, you want the surface of each strand to be independent. Soldering eliminates the surface of the many wires and makes them one big, fat wire with little surface area. If one was to maximize the utilization of all that surface area, one would not solder but allow all surfaces to contact one another and then contact the lug that connects to the terminal.

So, in conclusion... multi strand wire (welding cable) dry fitted with no dielectric, compression fitted with no solder, and sealed from the elements with a proper heat shrink tubing.

 

If I was a gambling man (which I am not) I would bet a nickel that the compression fitting with dielectric would be just a slight better than a solder connection. I would make my bet in the Angstrom's area of voltage readings for a fresh connection but I would suspect the solder connection would degrade over time as the hard to flexible connection would break strands over time and the solder would oxidize which would inhibit flow. At least with the free movement from the dielectric and the non-oxidizing properties of the grease, the surface of the wires would stay true for a longer period of time. This is splitting hairs, I know...

 

Wouldn't solder allow all surfaces to contact one another more easily?

 

Dielectric grease is for heat transfer. Use it under electronic modules to their heat sinks; ie., HEI module to dist housing; processors to their finned heatsink; etc.
IF you want conductivity along w/ superior corrosion resistance, then use the old grey anti-seize compound. I use it on the ends of most all of my wiring when using those shitty crimp on connectors (no matter what the size). It works great & lasts nearly forever on battery connections & others. I've been using it for about 39 years now.
DON't use it in places where bleed over to the next circuit could be a problem; ie., trailer plugs, computer connecters, etc. Use silicone grease in those.
R.F.D.

 

I forgot to mention; SOLDER Is still the best connection.
R.F.D.

 

I've got crimpers, so I crimp all my ends.

 

There is nothing inexpensive about quality welding cable! It was cheap for you because your friend gave the cable to you. We have to pay for ours.... I use the hammer crimp ends and have never had an issue. Quality cable, quality ends, regardless of type. No need to cheap out on one of the most important parts of you car.

 

I buy the crimp lugs myself, have a big T&B (Thomas & Betts) crimper at work and I bring in what I want to crimp and do it. Use a little strain relief for the installation and the connection should be good for eternity.

Bob