While it's true that Anderson
Powerpole connectors can be soldered, this is usually not a good idea,
for several reasons:
1) Soldering is weaker than crimping
because it interposes a soft metal-- and possible air voids-- between the
copper of the wire and the copper of the terminal. A properly crimped
connection places the wire in compression and the surrounding terminal in
tension, ensuring a mechanically strong joint.
2) Soldering adds resistance to the
connection. In a properly crimped connection, there are no gaps at all between
the wire and the terminal. However low the resistance of solder, it's higher
than nothing. In the extreme case, soldering is completely unacceptable for
joints in lightning protection systems, since the high current of a lightning
strike will hit the extra resistance of the solder, vaporizing it, producing a
small explosion and sending the current in search of a better connection to
ground-- for example, through your radio equipment. Crimping and welding are
the only acceptable options for those connections.
3) Soldering degrades the long-term
reliability of the connection. Some types of solder and flux can trigger
chemical changes that will embrittle copper wire. Solder also has a different
thermal coefficient of expansion than copper, so over time, heat cycles create
stress at the surfaces of the wire and terminal that can produce microscopic
cracks and eventual separation. I've found soldered connections in old radios
where the wires were physically loose within a visually perfect and undisturbed
sleeve of solder.
4) Soldering degrades the long-term
mechanical strength of the wire itself. When solder wicks up into stranded wire
or around solid wire, it makes the wire stiffer. The last point reached by the
solder becomes especially likely to kink and break because the transition from
the soldered section to the unsoldered section concentrates bending stresses at
that point. As with any stress concentration, this can lead to wires being
broken by relatively mild stresses, including simple vibration. Stranded wires
will die faster than solid wires, one strand at a time. I've also found many
soldered connections where the wire was broken off INSIDE the insulation, right
at that point, leaving soldered strands on one side of the break and loose
strands on the other.
Because of this tendency for
soldering to create stress risers, wires that have been soldered to Powerpole
contacts should have a cable clamp installed at some distance from the
connection to prevent the soldered joint from flexing. The Underwriters
Laboratories (UL) standards require such clamps, as Anderson Power Products notes on its own web site,
and when I was doing this kind of work, military and aerospace connectors were
not allowed to use soldered contacts at all.
In amateur radio and similar
applications, Powerpole connectors are almost always used with unsupported
stranded wire, and high-quality crimping tools will absolutely give the best
results. (And the same is true for ring and spade terminals, butt splices, and
similar connections. Crimp all of these, don't solder.)
On the other hand... in an emergency
situation, considerations of strength and long-term reliability can be ignored.
In my vehicle emergency kit, I carry a small butane soldering iron and solder
rather than crimping tools to go with a small assortment of electrical
terminals. - P.N.G.
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