Re: T&T: Soldering Battery terminals
This list generally prides itself on doing things right. I would avoid soldering large terminal lugs. All terminal lug connections should be crimped because the result is an electrically better and physically more durable connection. First, soldering makes the connection into solid wire, which is why the ABYC has the requirement (for the limited exception of battery terminals tat are soldered) that the joint be physically stabilized. Second, these large gauge wires are much harder to solder than that video implies. The trimmed wire must be pristine clean. The use of the liquid flux is essential. If there is the slightest oxidation on the wire strands, the solder won’t bond well, no matter how hot you get it. With inadequate heat for inadequate time, internal cable strands that are not visible may not participate in the bond. Any residual oxidation will result in a high resistance connection and continued oxidation over time. Finally, it takes a lot of heat and not a little bit of experience to make that solder flow. A swage-type crimp is the way to go.
Just my opinion...
Jim
Peg and Jim Healy aboard Sanctuary, southbound at Georgetown, SC
http://gilwellbear.wordpress.com http://gilwellbear.wordpress.com/
Monk 36 Hull #132
MMSI #367042570
AGLCA #3767
MTOA #3436
Jim, after seriously considering soldering vs crimping (swaging, actually), I agree with you 100%. There are just too many variables in soldering.
Larry Cruzen
"Lady Dottie"
42' Heritage East Trawler
Ten Mile, TN
On Nov 3, 2014, at 5:18 AM, Jim Healy gilwellbear@gmail.com wrote:
This list generally prides itself on doing things right. I would avoid soldering large terminal lugs. All terminal lug connections should be crimped because the result is an electrically better and physically more durable connection. First, soldering makes the connection into solid wire, which is why the ABYC has the requirement (for the limited exception of battery terminals tat are soldered) that the joint be physically stabilized. Second, these large gauge wires are much harder to solder than that video implies. The trimmed wire must be pristine clean. The use of the liquid flux is essential. If there is the slightest oxidation on the wire strands, the solder won’t bond well, no matter how hot you get it. With inadequate heat for inadequate time, internal cable strands that are not visible may not participate in the bond. Any residual oxidation will result in a high resistance connection and continued oxidation over time. Finally, it takes a lot of heat and not a little bit of experience to make that solder flow. A swage-type crimp is the way to go.
Just my opinion...
Jim
Peg and Jim Healy aboard Sanctuary, southbound at Georgetown, SC
http://gilwellbear.wordpress.com
Monk 36 Hull #132
MMSI #367042570
AGLCA #3767
MTOA #3436
Jim.
I agree that a solid crimp is essential. But there are three other very
important factors. The first is fine strands. The reason for this is that
in applications like welding for a given gauge the fine strands have a
lower resistance. That is why they are used in welding not just because
they are more flexible. The reason is Faraday's law, current only flows on
the surface of a wire not in it. This small difference in resistance does
make a difference at very high amperage. Also Home Depot wire with few
thick strands puts much more pressure on the lug connection. Tinned wire is
much more corrosion proof. Finally the connection must be sealed and the
lug must be closed at the bottom. If you don't like solder for the seal
Home Depot has a product called liquid tape which is a goo which thoroughly
covers and sticks to the wire over this a shrink tape which has been
carefully sized to make a smooth surface. For good measure I usually put a
final coat of liquid tape which which if nothing else is easy to do.
Peter Denton
On Mon, Nov 3, 2014 at 5:18 AM, Jim Healy via Trawlers-and-Trawlering <
trawlers@lists.trawlering.com> wrote:
This list generally prides itself on doing things right. I would avoid
soldering large terminal lugs. All terminal lug connections should be
crimped because the result is an electrically better and physically more
durable connection. First, soldering makes the connection into solid wire,
which is why the ABYC has the requirement (for the limited exception of
battery terminals tat are soldered) that the joint be physically
stabilized. Second, these large gauge wires are much harder to solder than
that video implies. The trimmed wire must be pristine clean. The use of
the liquid flux is essential. If there is the slightest oxidation on the
wire strands, the solder won’t bond well, no matter how hot you get it.
With inadequate heat for inadequate time, internal cable strands that are
not visible may not participate in the bond. Any residual oxidation will
result in a high resistance connection and continued oxidation over time.
Finally, it takes a lot of heat and not a little bit of experience to make
that solder flow. A swage-type crimp is the way to go.
Just my opinion...
Jim
Peg and Jim Healy aboard Sanctuary, southbound at Georgetown, SC
http://gilwellbear.wordpress.com http://gilwellbear.wordpress.com/
Monk 36 Hull #132
MMSI #367042570
AGLCA #3767
MTOA #3436
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If you'd like to review a very good primer on terminating battery
cables, with lots of pictures, here's a link:
http://www.pbase.com/mainecruising/battery_cables
After being thoroughly disappointed 15 years ago with the work done by
one of my boat builder's employees, I re-did all my large cable ends
with solder, instructed by a pro on how to do it right. Among other key
details: Hold the tinned cable end in a vise or some such, pointing
upward, and set the perfectly-fitted lug onto the cable end. Heat the
lug with a butane torch, with solder touching where the wire meets the
end of the lug, until solder is drawn completely upward into the lug.
This does a particularly good job of ensuring that solder fills the lug.
Despite having done what I thought was a really good job, and which
worked really well for some years, after 15 years I noticed that
starting the diesel had become more difficult. Upon close inspection,
at least 2-3 lugs (out of more than two dozen) seemed to have loosened
up somewhat. I read MaineSail's writeup, bought the recommended FTZ
crimper and all new top quality lugs, correctly sized to match the cable
and posts they were used on, and carefully re-did all ends per his
instructions. It was relatively easy, and I'm pretty sure now that they
were done in a superior manner. BTW the engine starts very well now.
Richard Cook
New Moon (Bounty 257, Volvo KAD44P)
On Nov 3, 2014, at 5:18 AM, Jim Healy gilwellbear@gmail.com wrote:
This list generally prides itself on doing things right. I would avoid soldering large terminal lugs. All terminal lug connections should be crimped because the result is an electrically better and physically more durable connection. First, soldering makes the connection into solid wire, which is why the ABYC has the requirement (for the limited exception of battery terminals tat are soldered) that the joint be physically stabilized. Second, these large gauge wires are much harder to solder than that video implies. The trimmed wire must be pristine clean. The use of the liquid flux is essential. If there is the slightest oxidation on the wire strands, the solder won’t bond well, no matter how hot you get it. With inadequate heat for inadequate time, internal cable strands that are not visible may not participate in the bond. Any residual oxidation will result in a high resistance connection and continued oxidation over time. Finally, it takes a lot of heat and not a little bit of experience to make that solder flow. A swage-type crimp is the way to go.
Just my opinion...
Jim
Peg and Jim Healy aboard Sanctuary, southbound at Georgetown, SC
Just to set the record straight - DC current flows uniformly throughout
the cross section of a conductor. AC current flow tends to migrate to
the surface as frequency increases. At the relatively low frequency of
60Hz, current flow is roughly uniform throughout the conductor. It is
at higher frequencies such as those of sideband radio that the current
flow is essentially purely on the surface of the conductor. So rest
assured that the heavy solid buss bar you are using on your DC
distribution panel could not be replaced with a thin shim of copper. DC
current is flowing throughout the entire bar, not just on the surface.
Tom Collins - Misty Sea
Hi Peter,
Observations and opinions...
One, I think we’re talking about DC battery cables here, so Faraday’s skin effect does not apply. It really doesn’t apply at 60Hz AC until you’re talking about long - very long - 500 mile long - transmission lines. This discussion is strictly an issue of Ohm’s Law, strength of materials and fabrication techniques.
Two, Big Box and hardware store residential equipment and wiring DOES NOT belong on boats. These materials are not made for marine environments, and the insulations (temperature, chemical and abrasion resistance) are not rated for marine environments. There is an extensive table of acceptable tinned and untinned wire types in the ABYC E11 standard; none of the residential-use materials are included.
Third, ABYC ONLY allows sealed terminals, never open end terminals, for battery cables.
I know people use these materials and downplay the value of the ABYC standards. The more familiar with the electrical standards that I become, the more respect I have for their content and the professionals who develop them. If you follow them, you not only improve the safety of the vessel, but you also improve the likelihood of long and reliable service life.
Again, only stating my own opinion…
Jim
Peg and Jim Healy aboard Sanctuary, southbound at Charleston, SC
http://gilwellbear.wordpress.com http://gilwellbear.wordpress.com/
Monk 36 Hull #132
MMSI #367042570
AGLCA #3767
MTOA #3436