Battery cables for cars & boats, DIY

At higher outputs, current, from the batteries I had detected an increasing voltage drop. So I decided to change and update the supply cables from the batteries, see picture, to a more correct solution. 

The solution was

• Cable lugs on all cables
• The lug is crimped and soldered to the cable
• Heat shrink tubes, with glue, to cover the transition between the lug and cable
• Battery terminals with M10 distributer

The first thing is to have a proper method for crimping the lug to the cable. My first thought was to hire a hydraulic crimper, to expensive to buy, but the ones I found was in bad condition and not really what I wanted. After some search I found the hammer lug crimping tool. On the other hand I really doubted that it would work ..... but after checking this Youtube video I thought I would give it a try. So bought this.

You can see my first attempt, 70 mm2, also welded, in the second picture where the lug is cut with an angle grinder.

Pretty OK, being the first attempt.... ? It is very hard to see the transition between the copper in the cable and the lug and no cavities at the crimp place.

Some thoughts

• Use a cable tie to make it  easier to mount the lug on the cable
• Use a sledge hammer to get proper power, when crimping
• I used a blowtorch to heat up the lug/cable
• Use lugs with an opening at the top, where You add the soldering tin
• Hold the cable in upright position when welding, lug up !
• Don't use to much soldering tin, it should not go down in the cable ! passing the place where the lug ends
• If You have more than one cable on the battery terminal, check the length of the M10 bolt !
• I didn't have a proper cable cutter for larger cable dimensions so used a hacksaw
• Use "Battery Terminal Grease" to avoid oxidation on the lugs

If handling very high currents and the cables will get very warm, dont use soldering thin, just crimp!!

And please don't use the standard way to interconnect the batteries in a bank !!!

Check out this post on how to interconnect. I used method 2 in my bank with 3 batteries.

In the pictures below I also moved the aft thruster, from the service batteries, to the engine start batteries.

Before

After