Battery Cable - Crimp or Solder

[John P]

I need to get a total of 5 battery leads made up, an earth from the battery to the isolator, then one from the isolator to both the body-shell earthing stud and the starter motor mounting bolt.   From the other side of the battery there is a lead to the floor mounted starter switch and then another on to the starter motor.

I was intending getting these made up by a supplier but it would probably be easier if I could make them myself so I could offer each up to more exactly determine the precise length required.

I'd always understood that crimp connections are better than soldered providing they are done properly but professional crimp tools are very expensive and some of the cheaper ones, which clamp up in a vice or are struck with a hammer, look as though they effectively just force a pointed tool into the terminal.

Bearing in mind concerns I've read on here about voltage drop do you think I'd be better to:

1. Stick with getting them made up by a manufacturer and hope I've measured the lengths sufficiently accurate.
   
2. Buy a low cost crimp tool and use that.
   
3. Solder them.
   

John.

[Renaud]

Hi John,
I always solder them and never had troubles.
Apart from that Vehicle Wiring Products propose them at around £3 or 4.
Renaud

[Steve Jones]

Whilst crimping is great, it's not, really, an option if you have to buy a decent crimper to do a job you'll do once a flood. I solder mine the only potential issue is melting the plastic insulation near to the terminal as you solder. However, you can avoid that with the following.

1. Cut back the insulation to expose enough bare cable to fill the open end of the terminal.
2. Clamp the terminal in the vice with the open end pointing upwards.
3. Apply flux into the open end.
4. Cut off a few short lengths of solder and place them in the open end.
5. Apply flux to the exposed end of the cable.
6. With the cable in one hand and a soldering torch in the other, heat the open end of the terminal until the solder in it melts.
7. Push the exposed end of the cable into the melted solder in the open end of the terminal.

I then normally put a short length of shrink sleeve over the joint of the terminal/cable to finish it off neatly.

Steve

[John Cornforth]

Not having access to a crimp tool, I have always soldered battery connections.  Electrically they are very good and stay good over time.  One downside is that the solder tends to wick an inch or so back along the cores making them difficult to bend afterwards, so form the shape you want first. This inflexibility also makes the cables theoretically more prone to vibration induced fracture, but if properly supported there should be no problem.  Finally, the heat can distort the last bit of the outer insulation or cause it to retract from the end terminal. The cure for this is to use a piece of rubber or heatshrink sleeving but you do need to remember to slip it over the cable first !

[Jack in the Box]

John,

I have sent you a PM.

Alan

[Steve Jones]

If you follow the method I described in the post above yours, John, then the solder doesn't wick back along the core and the insulation at the terminal end isn't affected by the heat.

Steve

[Peter Clayton]

https://youtu.be/lJsvl7JyFN0?t=146  (A PICTURE IS WORTH A THOUSAND WORDS)

[Colin Wilks]

Hi John
Your query was generated by a concern about voltage drop. What size of cable are you using?

[John P]

I was planning on 25 mm although I haven't bought it yet. 

Some have suggested using 35 mm which isn't that much more expensive but I'm a little concerned over flexibility / bend radius as it's for my "Ulsteroid" where the battery box is under the passenger seat.   

There's not much clearance between the front of the battery and the timber support for the front of the passenger seat so at least the live (positive) cable will have to run along in this gap and then turn through 90 degrees to run along the transmission tunnel to the floor starter button so this bend will need to be relatively tight.

John.

[Bela]

Is the more flexible cable of a jump start set a solution?