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]

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]

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]

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]

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]

Micron has a humungo lever action crimper the size of loping shears, probably a bit more expensive than the average person could justify pruchasing.

I bought (and justified, but hey, it's a tool!) a "half-mungo" crimper of that style. I was still shocked at how large they were when UPS handed them to me :shock: Haven't used them yet, but they look promising.

My rationale was that I was going to be making dozens of crimps (boat + RV), and I'm often in out-of-the-way places where shipping/waiting/picking up/driving to would be rather inconvenient and gas intensive. Plus I found in the past that when I planned for, and ordered, pre-made cables that when I went to put them in, they fit "about" right, but oftentimes could have fit in better if I had crimped one end, put the cable in position, and then removed it and made up the other end (exact size on the spot).

Now hopefully the crimper works as I expect and my theory pans out. Of course the other part of it is that I figured I could always re-sell the crimper once I'm done with most of my projects. Of course I've used that rationale when buying other tools, but have I ever actually turned around and sold them? NooOOOooo :wink:

Whenever I get to the windlass wiring I'll get a chance to try it out :thup If it works well, I'll be sure to mention it here on the forum just in case others are interested (I'll probably mention it if it doesn't work well too!).

 

[thataway]

Nice job and illustration!

In boating we go by ABYC standards:

"11.14.5.7 Solder shall not be the sole means of mechanical connection in any circuit. If soldered, the connection shall be so located or supported as to minimize flexing of the conductor where the solder changes the flexible conductor into a solid conductor.

EXCEPTION: Battery lugs with a solder contact length of not less than 1.5 times the diameter of the conductor."

National Standard Parts Associates, Inc. (Happens to be in Pensacola, and is the basic manufacturer of many of the crimped connectors) makes a number of connectors which are crimp, plus low temperature solder.

There has been this rumor that soldered connections are not allowed in boats (as is true in aircraft and some other industries). I can see the advantage of Ray's technique, where he drills a hole, and the majority of the solder will be near the head of the fitting.

What is not allowed is to solder and then crimp. There are a number of reasons for this, but primarily, there bond with the wire with the fitting, then requires breaking down of the solder. Solder is a poorer conductor of electricity, by 13 fold in comparison to copper.

The exception above is for the large battery terminals, such as 00 on up, where you have a long barrel on the lug, and it is 1 1/2 times the diameter of the wire in the cable.

 

[BrentB]

:thup

thanks for sharing


What are you using for sealant?

 

[Robert H. Wilkinson]

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