Battery cables

Now that I have 12 additional batteries I need to hook them up in parallel as I plan to continue with a 12 VDC system. Each of the AGM batteries has a top stud with a hole for a 5/16” bolt. A battery cable is held in place with this bolt.


I have chosen to use #4 AWG wire to interconnect.  The cable is rated at 96 amps DC and as I have no plans to draw more them about 75 amps DC, I should be OK. The total capacity of the expanded battery bank is now a bit over 1400 amp hours.


I started my search for battery cables on the internet and found, much to my dismay, that these things are quite expensive. The lowest price was a bit under $8.00 and many were over $20.00 each. The math was not looking good. A minimum of $16.00 per battery and I had 12 of them to hook up. That would be $192.00 on the low end and considerably more on the high end.


Time to build my own…..


I found a source for battery wire at $1.29 per foot. Connectors were $1.37 each.  Now I am down to about $4.00 per cable but the crimp tool for the lugs was almost $30.00. Hmmmm…… got to be a cheaper way.


As I looked at the wire I did a quick visual measurement and was sure I could get a small piece of hard copper tubing that would fit over the wire.


Off to ACE hardware and sure enough, copper tubing at $1.99 per ft would work just fine. By using about 1 3/8 inches of tubing and soldering the connections, using a propane torch, I was able to make a connector using simple hand tools … vice grips to flatten the tubing and a drill to make a 5/16 hole. Put flux on the wire and inside the tubing ……  presto a nice solder connection that is low resistance and costs about $0.25 cents per end.
















Now my cost of a battery interconnect cable was 12 inches of cable @ $1.29 per foot plus $0.50 cents for connectors, solder and flux from the work bench and I have a total of $1.79 for a 12 inch, 4 AWG battery cable. I will add some heat shrink from the junk box  - I think it cost me about $1.50 per foot or about $0.13 cents per inch …. Make it 1.5 inches per connection and I now have a cable that costs about $2.05. The finished product looks as good as the ones I would have ordered.


A considerable savings with a bit of work. …… $ 49.00 instead of $192.00 ……


The final version of the first batch of cables used the commercial connectors as I have them on hand and could not return them. With the addition of some heat shrink tubing, they turned out quite well.


The next group of cables will use my home-

Brew connectors. Once I get these made up

I will post photographs of the final product.


Total cost for the first batch of cables using

the commercial end connectors:

$1.29 for one foot of cable, $2.74 for

Connectors and $0.26 for heat shrink.

Grand total per cable— $4.29


For the next six batteries— 12 cables— it would have cost me, using the best prices I could find on the internet, about $96.00 plus shipping. Using my home-brew connectors, my projected cost for the next six is  $24.60.

$1.37 commercial



$0.25 cent


Text Box: My prototype  
The final version was filed smooth and cleaned after soldering. The hole was also centered

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