Battery cable connections?

[gbanker]

What are you folks using (tool) to attach terminal connectors to large size (#2, #1 and 1/0) battery cables? Thanks

[btrayfors]

The proper way to attach lugs to boat cable is with a large crimp tool made for the purpose. However, that is quite an expensive toy.

For many years I used a small tool which you hit with a hammer. It is sold in most marine stores. It works, but I've found that the connections are not great, even when great care is taken.

Recently, I discovered that a Nicopress tool works wonderfully. This is the one which uses a 5/8" wrench to attach Nicopress sleeves to s/s cable. Takes a bit of time, but does a fine job. Be sure you use the correct size lug to match the wire.

Whatever you do, be sure to use a bit of engine tuneup grease (dialectric), and shrink wrap or heavily tape the finished crimp. This provides both moisture proofing and support so the crimp doesn't "work" in the lug. Looks and works beautifully for many years.

Bill

[ssullivan]

Another way to get this all done is to go to a welding supply shop. They have all the battery connectors/lugs you could ever imagine. When I bought my 1/0 cable there, they used that expensive toy to drop the lugs on the end at no charge.

[By Invitation]

I have used the hammer style with great success and would recommend it to anyone. You do need a good solid surface to set it on and one hell of a large hammer. I have tested several connections by cutting them in half to inspect the quality and the wire becomes basically solid copper from the impact. When used properly they work as well as anything. I purchased mine for 7 dollars on Ebay used.

[cat man do]

Always used a big heap of heat and solder as well.

Dave

[coot]

I bought wire and terminals from a local store that would lend out their crimping tool. (Fawcett's in Annapolis, MD, US) It is shaped just like a bolt cutter, but instead of a sharp blade there is a groove on one side and a tooth on the other.

Another opinion:

I use the the hammer driven crimp tool as the mechanical connection, but I also solder to make sure I get a low resistance connection. Then cover with adhesive lined heatshink to make sure it stays that way!

Note that if you do it this way the solder is really just making sure that there is as perfect an electrical connection between the wire and the lug as possible. You do not need to fill the lug with solder. Just put rosin flux on the parts before assembly, make sure the lug and wire both get to temperature, and then flow solder into the teminal to wet the joint between them. I usually use a propane torch to do this, it seems the only way to get the fitting hot enough when you have that huge copper wire sinking heat away.

I do not trust solder only connections to have the mechanical strength of a proper crimp--and I don't trust the hammer crimp to get sufficiently tight contact to keep a good low resistance joint. Done together, I am happy.

Bill

[GordMay]

I would not recommend the combination of two inadequate termination techniques (hammered crimp & solder), in the unfounded expectation that each will remedy the deficiencies of the other.
I recommend the use of a properly sized ratchet crimper on all terminations, including battery terminals.
Although solder-only connections are permitted on battery terminals, it’s fairly difficult to achieve a good soldered connection, particularly on larger cables & terminals (requiring lots of heat).

Gord,

I hear what you are saying, but I wonder what you think failure of this system looks like. With the hammer crimp I get a mechanical junction strong enough that I can not pull them apart, before soldering. I do not know how strong is "strong enough" but I figure 150 lb force ought to be a reasonable "good enough", and they hold that without a trace of a problem. I test each joint I make like this, because one of the drawbacks of hammer crimping is that there is no absolute built in "stop" for the crimp.

I am naturally the careful type and well aware of the damage that can be done by the huge amperages flowing though high power DC circuits. So, after soldering, I installed a wire terminated like this on my inverter, powered up enough stuff to pull almost 200 DC amps. The voltage drop across the terminal (from post to wire) before adding the heatshink was unmeasureable (<1 mV.) What more can I ask? Guess I should have done a crimped but unsoldered terminal just for yucks.

I solder only high power cables. Everything else is rachet crimped with top quality tinned wire and terminals.

And a question about solder technique on large cables: I have many years of success soldering "normal" sized wires and electronic parts. As Gord implied in a previous post, above a certain size, (is it 1/0?) solder joints are accepted as a means of joining terminals to cables, although I am not sure I would trust it. Enough solder to make a strong mechanical joint seems like it would invariably result in an inflexable length of cable that would fail if regularly flexed.

Now for the question: No matter how fast I heat the end of the terminal (propane touch), the cable can wick away the bulk of the solder. Solder wicked up the cable does nothing good for the joint. Quite the reverse, it just becomes stiff and susceptable to fatigue failure. Am I missing a key technique step here that is unique to massive solder jobs? Or have I got it right and just have unrealistic expectations of what a large solder joint should look like? With tinned wire and tinned lugs, I add just enough solder that I am sure the two are well wetted together, and then stop.

I don't plan on using solder only connections for my battery lugs, just trying to learn if there is a better technique for the connection.

[Sandero]

I believe solder is not recommended for wire terminals by the pros. They recommend crimped connections with sealed heat shrink sleeves (with glue) to prevent moisture penetration.

Jef
sv Shiva
Contest 36s

[GordMay]

An electrical termination must exhibit both of two important qualities:
1. Low electrical resistance.
2. High mechanical strength (pull-out force)

Hammer-Crimped terminations may exhibit a high enough pull-out resistance through small, but very tight, point contact.
A point contact will provide a small contact (lug/wire) surface area, resulting in increased resistance.
Hence, a termination could be “strong”, and still exhibit an unacceptably high (& potentially dangerous) resistance.

BTW: 150 Lbs pull-out force is the minimum specified for 2/0 AWG cables
(see ABYC “E8", Table IV or my Wire Sizing Chart (far right column) at http://www.cruisersforum.com/gallery...age.php?i=1321 )

Solder-Only terminations are only permitted on Battery Lugs, not all larger guage cables.

[hellosailor]

I've been told by a licensed master electrician that the only right way to crimp those lugs is with a hexagonal crimping tool. I told him that was nice, but wasn't gonna happen on my planet unless MacDonald's starting giving away the tools with Happy Meals.

As a practical matter the last cables I crimped were 4-AWG. For most of them, I called up the local (Ahem) Marine store and said "IF I buy the lugs from you, can I use your crimper?" and they said yes. Well, Ancor lugs ain't cheap but they are sealed (not open) and fully tinned, so most of the cables got crimped that way.

And, against all advice (except elevator motor mechanics, who apparently insist on soldering all heavy power cables including these sizes!) I also soldered--but by inserting solder paste ("Solder-It") into the cable before crimping. I expect the paste flowed out into spaces and allowed a full and proper crimp. Afterwards, I hit it with a small torch until flux bubbles out indicating I've got the solder bond in there as well. Ask me again in ten years if that works out well.<G>

But one cable needed to be made up extra, with no resources except the auto shops (Huh?) heavy tool/hydraulic rental (Huh?) and the local Home Depot, where a Jamaican employee with a "can do!" attititude simply put it in a vice and squeezed the damned thing down nice and tight. What can I say...that fitting doesn't look as pretty, but two years down the line it still is holding up perfectly well.

Tried the Nicopress--but it isn't easy on large lugs!

I think the bottom line is that how much attention you pay to matching lug and cable sizes, and how carefully you do the job, count for as much as everything else. Meantime...I've been thinking about having some 1/2" plate machined down with hex cuts in it, couple of big bolts, and making up my own "proper" crimping tool to use that way. Kinda amazing that there's "amateur night" junk out there, and $300 professional crimpers designed for thousands of uses, but nothing in between!

Originally Posted by GordMay

An electrical termination must exhibit both of two important qualities:
1. Low electrical resistance.
2. High mechanical strength (pull-out force)

Hammer-Crimped terminations may exhibit a high enough pull-out resistance through small, but very tight, point contact.
A point contact will provide a small contact (lug/wire) surface area, resulting in increased resistance.
Hence, a termination could be “strong”, and still exhibit an unacceptably high (& potentially dangerous) resistance.

So... with the addition of solder to the mechanically strong but electrically marginal hammer connection, what's to go wrong? Especially since my load testing seems to show a very low resistence?

Originally Posted by GordMay

BTW: 150 Lbs pull-out force is the minimum specified for 2/0 AWG cables
(see ABYC “E8", Table IV or my Wire Sizing Chart (far right column) at http://www.cruisersforum.com/gallery...age.php?i=1321 )

Trust Gord to have the reference handy! I'm at the office and don't have the boat books to hand... Thanks Since the largest cables on my boat are 2/0 it seems my test method is about right.

Originally Posted by GordMay

Solder-Only terminations are only permitted on Battery Lugs, not all larger guage cables.

Of course, I should have been more specific in my comment, and if I remember correctly the battery lugs have to be 1.5 times longer than the cable's diameter and need additional support becuase of the loss of flexibility.

[Bradley]

Are there any reasonably good and not horribly expensive solutions for being able to make crimps on the boat. It always seems like that when I need to make a crimp, I am someplace where no crimping tools are available.

About a year or so ago another boater loaned me a tool that was a lot like an old style flaring tool. It seemed to work really well. I can't seem to find one of them.

Any suggestions would be greatly apreciated.

[btrayfors]

I assume you're talking about crimping lugs onto battery cables, or other large-size wiring.

One solution which works well is to use a NicoPress tool. These are sold at West Marine and other chandleries. They come in two sizes; the larger one can handle most battery lugs nicely. You just need a 5/8" box wrench to operate the tool.

Two other things are important: (1) quality lugs; and (2) quality heat shrink.

Some of the best lugs I've found are carried by GenuineDealz.com - Marine Electrical, Boat Wire & Cable, Custom Battery Cables

You can find heavy adhesive-lined heat shrink at Plastic Heat Shrink Tubing : Braided Wire Sleeving : Nylon Cable Tie : BuyHeatShrink.com : Expandable Sleeving : Gun : Tube : Printer

There are a couple of crimping tools operated by hitting them with a hammer, but IMHO these are inferior to the NicoPress tool solution, and grossly inferior to a proper hex crimp tool (like the Greenlee).

Bill