There REALLY are reasons...

[BlackOak]

plenty of Dielectric Grease

[jsanton]

Sorry folks, I didn't read the entire thread. But, I am an engineer and understand the technology.

If you solder a connection, it creates a stiffness discontinuity at the edge of the solder. This discontinuity focuses flexing and the attendant work hardening and breakage. If the cable is 100% tied to the same mechanical structure as the terminal, then the problem of work hardening can be avoided. However, this is very difficult to achieve in an environment with vibration.

The thing that makes a crimp different is only visible in your mind's eye or with a microscope and a cross sectioning tool. The crimping die has a curved surface to it. This makes the center of the crimp force the material into a "like solid" compression, but from the center to the edges of the crimp, there's a tapering of the compression load. This effectively avoids the stiffness discontinuity problem mentioned above.

Hopefully, a little bit of academics is of some value here...

[Ballsnall]

Originally Posted by jsanton

But, I am an engineer and understand the technology.

Well that's settled it then.

[Ballsnall]

Originally Posted by AKA-None

I hope everyone here understands that in a proper crimp there is no place for solder to flow as everything is sealed
I guess that’s why they call them gas tight

I don't understand that, and it has not been my experience that you cannot solder a crimp connection. Most of the discussion here has been about crimp v solder but my view is the discussion should be about crimp v crimp + solder, I would never solder alone.

In my experience broken wires from fatigue is a non issue, extremely rare and usually with exceptional circumstances. The most common connection issues with terminals is the green death (corrosion) and it's for this reason that I crimp AND solder which eliminates or at least minimises the issue of corrosion at the terminal. And contrary to claims that the solder doesn't penetrate the crimp, this has not been my experience especially with battery cables. One downside to consider is that the solder does actually increase resistance but it's a very minute amount.

[Lake-Effect]

Originally Posted by Ballsnall

The most common connection issues with terminals is the green death (corrosion) and it's for this reason that I crimp AND solder which eliminates or at least minimises the issue of corrosion at the terminal.

... but there are alternatives that will also minimize crimp corrosion, with less effort and risk to the connection. If you use the adhesive heatshrink type crimp lugs, and after crimping you push a dab of dielectric grease or similar protectant into the lug end of the crimp barrel, then you've also sealed the bare wire and crimped connection from the environment... without the hassle and plastic-melting of soldering.

See also Boeshield T-9 and similar products, discussed on CF over here.

[AKA-None]

Here’s some photos and as you can see a good crimp leaves no place for solder

https://www.etco.com/engineering-guides/

[team karst]

I dont see this mentioned yet: 60/40 solder has close to 10x the resistivity of copper. In case you wanted to hear more reasons not to solder high current lugs.

[Cheechako]

Seems a heavily crimped end fitting is rigid also? I have seen many broken wires at the unsoldered end fitting.
Not to mention the myriad of failures where the exposed wire at the end fitting corrodes and breaks, where flowed solder might help avoid that?
As with anything, where and how you use it is the key.

[team karst]

Originally Posted by Cheechako

Seems a heavily crimped end fitting is rigid also? I have seen many broken wires at the unsoldered end fitting.

Not to mention the myriad of failures where the exposed wire at the end fitting corrodes and breaks, where flowed solder might help avoid that?

As with anything, where and how you use it is the key.

Use closed ended lugs and semi-rigid adhesive lined HS.

[thinwater]

Just like an anchoring thread. Easy to do right, easy to do wrong, and easy to critique.



And FWIW, you are allowed to use solder-only on battery lugs. There are several reasons this exception is permissible.




And yes, even ABYC (IMO) has questionable stuff in it. I watched a truck catch in fire because of the below practice. The truck had been parked for an hour, the battery cable and the fuel both chafed on a frame where they were secured to each other (there was a nice grommet, but it had worn through), and the truck started to burn, while fuel was siphoning from a full 100 gallon tank. The only reason we didn't lose a whole row of trucks is that we were sitting around chatting before going home, and we had the fire out within moments with minimal damamge (other than two guys covered in dry chemical!). I would not secure a wire to a fuel line anywhere chafe is even remotely possible.

[GordMay]

Originally Posted by team karst

I dont see this mentioned yet: 60/40 solder has close to 10x the resistivity of copper. In case you wanted to hear more reasons not to solder high current lugs.

INDEED!


Note: Electrical resistivity [ρ] is not the same as electrical resistance [R]; tho' resistance depends upon resistivity.

Electrical resistance [the reciprocal of electrical conductivity] is expressed in Ohms [Ω]. While resistivity is a material property, expressed in ohm-metre [Ω·m] resistance is the property of an object.
In most conducting metals, including copper, the resistivity increases with increasing temperature.

Copper has the highest electrical conductivity rating, and therefore the lowest resistivity rating, of all nonprecious metals [gold & silver].

Perhaps some basic formulae explain it better:

Resistance:
R = V/I or,
R = ρ(L/A)
V = Voltage, I = Current, ρ = Resistivity

Resistivity:
ρ = (R×A)/L
R = Resistance, L= Length, A = Cross-sectional area

[team karst]

Good followup !

[pbmaise]

Originally Posted by CarinaPDX

When I built Carina I ran a 12VDC power line on each side of the boat, in a PVC conduit just under the deck along the hull. These lines were for lighting and some other small applications. I used PVC tees where I needed, and stripped the wires and wrapped the branch wires around the bus wires, soldering and covering properly. This ensured a reliable through connection as the bus wire was never broken. In order to do this I left a small loop at each tee, and tucked it inside when finished. In the 40 years or so since I did this I have never had a failure, although admittedly a small sample. I would be genuinely interested in how I might have accomplished that job better with crimps, using today's options (extra credit: with options available in 1980).

Greg

Greg, I am very pleased to read about this method. I have been a strong advocate of a bus like wiring method. There were dozens of wires running below my floor boards. That translated into hundreds of feet of wire I didn't believe was needed.

[Lake-Effect]

Originally Posted by pbmaise

Greg, I am very pleased to read about this method. I have been a strong advocate of a bus like wiring method. There were dozens of wires running below my floor boards. That translated into hundreds of feet of wire I didn't believe was needed.

The potential problem with the bus-wiring idea is that the bus will have fuse or breaker overcurrent protection sized for the bus conductors, but if there isn't also protection for smaller-guage branch that are connected to the bus, at the point where the branch connects to the bus, then there is a risk that a short or excess current draw on the branch conductor could heat the branch wiring up to fire-igniting temperature without tripping the bus fuse/breaker.

And I don't much like the method of baring part of the bus wires, wrapping the branch wire around a few times, then soldering it, then taping or tubing it all up, and it gets hidden.

For this reason, I prefer the use of subpanels for distribution where it would be more efficient than running everything back to one panel. This is approved by every electrical code that I'm familiar with.


Crimp/solder battery terminals - lots of opinion on that, for sure.

ABYC E-10.8.2 allows solder as the sole means of attaching battery lugs IF the length of the soldered lug-to-wire area is at least 1.5x the diameter of the wire. The former head of the ABYC electrical committee disagreed with this, but was apparently overruled.

Me - I like'em crimped. Not many people know how to properly solder heavy cable with a torch, and it's pretty easy to find a friend or a marine shop that properly will do the few needed crimps, using good tools.

[team karst]

Highly distributed OCP devices. And switches, unless using networked controller. Consider how to do the nav lights, as one example.