Adios
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yes the point has been made and taken, my bad!
Terminating large cables
- Thread starter lustyd
- Start date
PaulRainbow
Well-Known Member
Nothing wrong with welding cable, but it isn't normally tinned (also nothing wrong with using non-tinned cable in appropriate locations).
I don't understand you 2nd paragraph. Welding cable, battery cable, OceanFlex cable, generally have the same stands, the hydraulic crimper works perfectly on all three. Number of strands is surely irrelevant anyway, 35mm cable is 35mm cable, regardless of how many strands are needed to make it 35mm.
noelex
Well-Known Member
The properties of the outer sheath or the insulation of the marine wire does vary with different qualities and brands of cables.
The temperature rating has a significant effect on the current carrying capacity.
Voltage drop is often the prime determinant of wire size in a marine environment, but current carrying capacity can be important in some applications.
For example, depending on what standard you apply, 35mm wire in an engine space is safe for around 130A if the insulation is 75°C rated. This increases to over 200A for 125°C rated insulation. A significant difference. Note: please consult the proper tables. The above is only an illustration. Factors such as if the wire is bundled will effect the recommendations, as well as the standards adopted by various countries.
There are other considerations for wire insulation such as oil and abrasion resistance etc etc.
The temperature rating has a significant effect on the current carrying capacity.
Voltage drop is often the prime determinant of wire size in a marine environment, but current carrying capacity can be important in some applications.
For example, depending on what standard you apply, 35mm wire in an engine space is safe for around 130A if the insulation is 75°C rated. This increases to over 200A for 125°C rated insulation. A significant difference. Note: please consult the proper tables. The above is only an illustration. Factors such as if the wire is bundled will effect the recommendations, as well as the standards adopted by various countries.
There are other considerations for wire insulation such as oil and abrasion resistance etc etc.
PaulRainbow
Well-Known Member
Regarding those anvil type tools, save you money and just thrash the lug with a hammer and punch, or squash it in a vice, it won't be any worse a connection. Soldering would be a better job, if you can solder well.
If battery cables are worth making yourself, please make them properly. Some of the ratchet crimps can make a decent job, if you don't mind putting some effort in. Without doubt, hydraulic crimpers are the best choice, they are easier to use and if you pump them until they won't squish any more you'll be sure of a good joint.
If battery cables are worth making yourself, please make them properly. Some of the ratchet crimps can make a decent job, if you don't mind putting some effort in. Without doubt, hydraulic crimpers are the best choice, they are easier to use and if you pump them until they won't squish any more you'll be sure of a good joint.
pvb
Well-Known Member
I've only done a major battery re-wire once, on my last boat, and I "crimped" the terminals with a Mole wrench and then soldered them using a gas blowtorch. Wet kitchen paper wrapped around the insulation stops it burning. All worked fine for many years.
rogerthebodger
Well-Known Member
The point about soldering is the possibility of the solder wicking up the wire and making the wire rigid so, if subject to vibration could break due to fatigue.
So if no vibration or the wire is clamped to prevent fatigue there should be no issue.
As I said I soldered my battery welding cables as you did and have had no issue.
lustyd
Well-Known Member
I take your points, but it seems to me that if a £20-£30 tool can do the job more easily, more consistently, and in place so I can get the twist on the cable right why would I spend the effort doing differently?
Either way I've ordered my tool now so fingers crossed!
Either way I've ordered my tool now so fingers crossed!
noelex
Well-Known Member
I am a fan of soldering. It produces a great, low resistance electrical connection. The main problem is that in a fault condition the joint can overheat and potentially the solder joint can reach its melting temperature releasing the wire.
Therefore, it is generally better to have a mechanical connection as well as a solder joint.
I use this dual process for most of my marine electrical connections. This is not practical for commercial installations, as it is very time consuming. For a DIY application this “belt and braces” approach is worth considering.
Therefore, it is generally better to have a mechanical connection as well as a solder joint.
I use this dual process for most of my marine electrical connections. This is not practical for commercial installations, as it is very time consuming. For a DIY application this “belt and braces” approach is worth considering.
PaulRainbow
Well-Known Member
Do you solder then crimp, or crimp then solder ?
noelex
Well-Known Member
Always crimp then solder, otherwise in a high temperature fault condition the solder can melt releasing the crimp and therefore defeating the purpose, although the temperatures that produce this will often melt the wire insulation likely creating problems before he solder melting is an issue. Still the combination of a mechanical conection combined with soldered connection is the ideal option.
If the soldering is applied on the connector side of the crimp, assuming a gas tight crimp the solder will not influence the flexibility of the joint but will provide a second and independent electrical and mechanical connection. Belt and Braces.
This is overkill. Crimped connections are perfectly fine on their own, but crimped connections are only ideal with calibrated wire connection terminals and crimping tools. For the amateur crimpted and soldered connections provide some added security and the extra time involved is less of a concern.
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PaulRainbow
Well-Known Member
Agreed
But surely, if the crimp is gas tight, there is nowhere for the solder to go, other than to lightly tin the connector and any exposed wire, which there shouldn't be. So i can't see that providing any independant mechanical strength or additional electrical connection.
Yup, definitely overkill, but if it keeps you happy, who am i to argue.
For the average DIYer, i'd suggest ratchet crimping anything up to about 6mm, then hydraulic crimping anything bigger, using good quality terminals. Both tool can be purchased for less than £40 theses days and it's hard to make a bad connection with the proper tools.
jwfrary
Well-Known Member
The idea of the big cables is to reduce resistance so the charge or discharge is evenly spread. Though there are other ways to do it. Buss bars etc.
Boats are as with all things often a compromise between what’s technical perfection and what’s achievable in a space and with a budget!
(I usually go with interconnects twice the size of the distribution cables)
pvb
Well-Known Member
A bus bar won't ever reduce the voltage drop in an undersized cable.
Gary Fox
N/A
This is the cable I've bought for my windlass, tinned welding cable, 
and I will use those hydraulic crimpers.
and I will use those hydraulic crimpers.
Gixer
Well-Known Member
I bought a hydraulic crimper a few months ago when I rewired some my boat. Was only a cheap £30 tool but I’ve been super impressed, well worth the money. Best thing is you can leave the wire in situ when crimping unlike the anvil type.
I‘m slowly going around my whole boat now replacing all the old connections with new crimps.
I‘m slowly going around my whole boat now replacing all the old connections with new crimps.
noelex
Well-Known Member
If you have a 12v system it is often surprising the size of cables that are needed. If Bavaria are using larger cables than most they are to be congratulated.
For example if we limit voltage drop to 3% ( so 12.5v at the the batteries will be 12.13v supplying the appliance) larger than a 95mm cable would be required if the device has a total cable run of over 7m (one way) and the draw is 120A or higher. This is just one example, but it shows that for modern nedium or large yacht 95mm battey cables are not necessarily overkill, especially when considering battery cables may be required to supply multiple high draw devices.
For example if we limit voltage drop to 3% ( so 12.5v at the the batteries will be 12.13v supplying the appliance) larger than a 95mm cable would be required if the device has a total cable run of over 7m (one way) and the draw is 120A or higher. This is just one example, but it shows that for modern nedium or large yacht 95mm battey cables are not necessarily overkill, especially when considering battery cables may be required to supply multiple high draw devices.
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starfire
Well-Known Member
With the Chinese crimper, I have had some crimps, that were loose, I always give the crimped lug a good pull to check. Using next size down gives a solid crimp, even if there is some 'flash' on the edge.
May be that the dies i have are not particularly well specified.
PaulRainbow
Well-Known Member
I've seen other comments about loose crimps, not sure if some of the dies are a bit iffy or if people are using terminals that vary a bit in size. As you say, if it isn't well crimped, come down a size on the dies
PaulRainbow
Well-Known Member
I've not seen such thick cables on any other mid 30ft production yachts. I suspect that they have a "one size fits all" policy for the wiring harnesses, so a slightly basic model will have battery cables capable of supplying every conceivable extra.
Voltage drop often gets ignored on 12v systems. There was a recent thread about bow thrusters where an industrial electrician insisted 95mm was applicable for a 7m-7.5m one way cable run for a bow thruster drawing 200a.He said it was "more professional" than running two 95mm cables, which the manufacturer recommended.
JumbleDuck
Well-Known Member
At 0.193 ohms/km (BS6346 Cables|Technical Reference) that would be a total voltage drop of 0.6V. Doesn't seem toooo bad.