With all of this talk of batteries and wiring

Ray

I put together a few pictures on how an overly-anal geeky engineer (me) makes up a battery cable.

First strip the cable to match the ferrule of the lug

Then crimp the lug to the cable

Make sure the crimp has a VERY good mechanical connection on the wire

Next, I put the lug in a vise and drill a small hole in the void just past the end of the wire

Heat the lug with a torch until it is quite hot

Melt solder into the hole and allow it to wick into the end of the wire. Allow it to seal up the hole

Seal off the gap between the lug and the wire sheath, as well as the hole with sealant

Cover everything with an appropriate length of adhesive-lined heatshrink tubing

And there you have it - the very BEST wire-to-lug connection that I can think of. I have been doing these on an embarrassing number of boats for 15 years and never had a failure, corrosion, or increased resistance of any kind.

Just my version,
Ray

Foggy · Posted: Sat Jun 21, 2014 7:27 am Post subject:

Very neat. I too appreciate small things done precisely and well.
It would make sense to Grandma who used to say, "The Devil is in the details".
And it nicely fits the All Things Electrical Mantra of "clean", "dry" and "tight".
Congratulations to your parents for supervising your fastidious potty training!

Aye.

Pat Anderson · Posted: Sat Jun 21, 2014 10:09 am Post subject:

The guy at Microtech (the US distributor for Victron) made three short battery cables for me, one to go from the Victron shunt to the battery's negative terminal, and two to replace the wires I was using to connect my house batteries in parallel. No solder or sealant but he said the heat shrink was absolutely essential. He makes hundreds of power cables for his largest customers, the Navy and the Coast Guard, and they do not tolerate failed cables well!

Your crimper is pretty cool - is that a custom design or an off the shelf item? Have never seen one like that. Micron has a humungo lever action crimper the size of loping shears, probably a bit more expensive than the average person could justify pruchasing.

potter water · Posted: Sat Jun 21, 2014 10:21 am Post subject:

In the aviation business, it is against practice to ever solder a lug. The reason is that the point of having stranded wires is the flexibility. A solid wire will cold work and break. Soldering the stranded wire in the lug essentially reduces what was flexing stranded wire to a single solid wire that will cold work and break.

That said, all the other steps look really good. Also, in the boat environment I don't think there are enough vibration sources to cause any grief. If the soldering makes you happy that's good enough for me. But it probably is not correct for the application.

The healthy crimp you show will be more than adequate for life long wire retention without the solder.

So, don't get me wrong, I'm not being critical of your method, I love the finished product. Just passing along an electrical/aerospace engineers experience.

Ray · Posted: Sat Jun 21, 2014 10:37 am Post subject:

Pat - I bought the crimper online from one of the EV (Electric Vehicle) DIY web sites. As you can imagine, they use these a lot.

Potter - very good point/reminder. I would never use solder on anything thinner than, say 8AWG, depending on the application, for the points you mention. With the large diameter cables, and when secured close to the connection point, vibration is not much of an issue.

Thanks.

Sunbeam · Posted: Sat Jun 21, 2014 10:55 am Post subject:

thataway · Posted: Sat Jun 21, 2014 1:42 pm Post subject:

Nice job and illustration!

In boating we go by ABYC standards:

BrentB · Posted: Sat Jun 21, 2014 6:35 pm Post subject:

thanks for sharing

What are you using for sealant?

Robert H. Wilkinson · Posted: Mon Jun 23, 2014 10:42 pm Post subject:

I made my own crimper for battery cables - quite similar to the one in the picture. Not hard to do and inexpensive. It did require the use of an torch and mig welder to make though.

I have tried adding solder to the lug but personally I have found that a good crimp provides a secure mechanical bond and combined with a good quality sealant filled heat shrink installed as in Rays pictures results in a quality connection.

My best advise - don't scrimp on the heat shrink. The type with the sealant inside that melts as it shrinks is best and extend it up the wire for a couple of inches. This helps support the wire to lug joint and limit cold working as Potter mentioned.

When doing multiple cables I have bought black wire by the roll and used red heat shrink on the positive lugs. If necessary for identification you could add a small cut of the red heat shrink every foot or so along the run.

Regards, Rob