soldering a battery lead

[sarabande]

I went on board yesterday for the first time on a couple of weeks. Job #1 is to reconnect the batteries, as I always disconnect them when leaving (), and then to run the voltmeter over them.

Generator batt (Single 12v 110 AHr) OK at 12.6

Domestic batts (serial 2x110 AHr) OK at 12.5v each

Engine Batts (serial 2x110 AHr) OK at 12.5 ish each, but when checked across the 24v terminal - OOPS ! zero, nada, 0 volts at all.

A little bit of investigation came up with this: the small + to - connection had come unsoldered.

Now I have a small soldering iron (which is clearly not going to be tough enough/have enough heat), and a butane gas jet/torch. What I don't know - as I have soldered anything on this scale before) is how to get the heat into the pinch clip and the cable, and what sequence (i.e. do I heat them separately, join them and then apply the solder core; or join them, heat them and then add solder.) My other concern is not burning the insulation.

All advice gratefully received ! Thanks.

 

[SimbaDog]

The way I have done that before is to make sure the components are clean, insert the lead onto the connector, snug it up with pliers if needed & then gently heat the connector with the blow torch, feeding solder in the top seam as soon as it is hot enough. Tricky & best done if you can clamp things in place as they get pretty warm!
Good luck

 

[Bilgediver]

The way I have done that before is to make sure the components are clean, insert the lead onto the connector, snug it up with pliers if needed & then gently heat the connector with the blow torch, feeding solder in the top seam as soon as it is hot enough. Tricky & best done if you can clamp things in place as they get pretty warm!
Good luck

I suspect that this assembley is the actual problem and not really fit for purpose.

You need to get two decent clamp connectors and use a short U loop of starter cable between the batteries. This will prevent the vibration from the batteries getting to the soldered joint.

 

[VicS]

Bilgediver is probably right. A decent loop of cable with terminals ( the battery clamps even) properly crimped on.

but I would re-solder it.

Degrease and clean it all up, then get it cleaner!

Fit the lug on the cable using some soldering flux paste suitable for electrical work.
Heat the lug until you can feed some solder into the joint.

The secret I think will be to use sufficient heat to be able to work quickly so as not to affect the other end. cool quickly without moving the joint.
Holding the terminal at the other end in a vice ( without jaw protectors) will help to keep it cool.

I think I would also critically inspect the other end and if in any doubt re-solder that too.

Follow Bilgediver's advice.

 

[elton]

To avoid damage to the insulation, grip the terminal firmly with pliers just next to the insulation. The pliers will act as a 'heat sink'. When you see the solder flow throughout the joint, remove the heat source. It's very important not to move anything until the solder has cooled to the point of being solid, otherwise you'll end up with a brittle or 'dry joint' which will probably fail very soon. The good joint should appear bright and shiny, rather than a dull gray.

 

[savageseadog]

I would crimp it or get it crimped by an auto electrician

 

[ccscott49]

This is not the sorrect way of doing things, get new terminals, with wing or normal nut connections and a short piece of flexible battery cable, with crinped on eye ends. Which wont snap with vibration.
That connection is an accident waiting for somewhere to happen, probaly at sea. Do it once, do it right.

 

[ShaunG]

I would go for crimps.

in fact, as there seems to be lot of questions on here regarding this issue, if any one is in the region of the chichester area they are more than welcome to borrow my poper battery cable crimpers (makes a hexagonal crimp in the terminal) or i will happily do it for you when i am around at the weekends (no cost of course). The crimpers will crimp upto 55mm2

 

[Scotty_Tradewind]

When I crimp I now also solder. (even though some throw scorn on this practice I find it bullit proof)
If soldering terminals of that size I would use a small gas flame to spread heat quicker.( heat sink....good idea to stop spread of heat if req'd)
When I solder I use flux to help the solder run and to help any non super clean surface take the solder.
When you solder you need a loop of cable to absorb vibration.
good luck
S.

 

[Networks]

I would not solder, you need to crimp using a calibrated crimp tool and the correct size lug for the cable. Now I bet you dont have that kind of kit in your back pocket do you?
If you PM me with the details, i.e. bolt size + cable length required (allow for a "U" to minimise vibration) and I can send you a short link made up.
If you are quick I could do that today, later this evening I will be on my way to Plymouth. Failing that it will be Tuesday next week before I could send it.

 

[elton]

The difference between a soldered joint and a crimped joint is that whereas a crimped connection is simply a mechanical, contact joint, a soldered joint is a molecular bond. The soldered connection being far more resilant to vibration and electrolytic corrosion failure. Maybe someone with more expertise than myself, a one-time electronics technician qualified to work on RN battleships, could correct me if this isn't so.

 

[ccscott49]

I will correct you, a soldered joint is more likely to fail on battery leads, than a crimped joint, but of course you dont need to believe me, maybe your training is a bit out of date? Crimps have replaced many soldered joints, due to stress/fatigue fractures and most certainly on battery connections.

 

[elton]

I will correct you, a soldered joint is more likely to fail on battery leads, than a crimped joint, but of course you dont need to believe me, maybe your training is a bit out of date? Crimps have replaced many soldered joints, due to stress/fatigue fractures and most certainly on battery connections.

Show us some evidence please. I'm not after an argument. If I'm wrong I'd rather not be giving duff info.

 

[nedmin]

soldering

whats all this about soldering,if its done properly it will last forever.I would trust a good soldered connection any time against a crimped one.If its that bad why do they solder armatures on motors.these whirl round at 1000,s of revs a minute and carry amps at the same time.I,ve seen too many bad crimped joints in my working life to get too keen on them,especially on aluminium cables.

 

[nedmin]

soldering

ps if there is any green(copper oxide) on the cables you are trying to solder,pour some boiling water on it, might also not be a bad idea if there isnt, because it will get rid of any grease for you.

 

[ccscott49]

No worries, I understand you are not looking for an argument.
The reason I was taught, was the soldered joint, especially on battery/starter cables, was the hard end of the wire, due to soldering, failed due to vibration/flexing work hardening the joint or similar which caused first cracks, then corrosion, (stress crack corrosion failure) then total failure, This was on mainly vehicle wiring, but also on aircraft wiring, as I was an aircraft tech first then artificer vehicles (long story). Of course as the other poster said, armatures etc are still soldered, I would love to see a method of crimping an armature! or circuit board, But the joints themselves are not subject to flexing and work hardening.
Cant quote any more detail than that, given time, I'm sure I could find something, but I'm at anchor in Puerto Soller, Majorca and cant really be that fussed! Cold beer, aft deck etc.

 

[philip_stevens]

I went on board yesterday for the first time on a couple of weeks. Job #1 is to reconnect the batteries, as I always disconnect them when leaving (), and then to run the voltmeter over them.

Generator batt (Single 12v 110 AHr) OK at 12.6

Domestic batts (serial 2x110 AHr) OK at 12.5v each

Engine Batts (serial 2x110 AHr) OK at 12.5 ish each, but when checked across the 24v terminal - OOPS ! zero, nada, 0 volts at all.

A little bit of investigation came up with this: the small + to - connection had come unsoldered.

Now I have a small soldering iron (which is clearly not going to be tough enough/have enough heat), and a butane gas jet/torch. What I don't know - as I have soldered anything on this scale before) is how to get the heat into the pinch clip and the cable, and what sequence (i.e. do I heat them separately, join them and then apply the solder core; or join them, heat them and then add solder.) My other concern is not burning the insulation.

All advice gratefully received ! Thanks.

I have just had to re-solder a 16mm earth wire into a tag on a ship. To prevent burning the insulation, I wrapped a wet rag around the outer insulation.

To prevent de-soldering the other end, allow it to rest in water. This way, it will not de-solder - even the wet rag should prevent de-soldering. Apply heat (maybe from a small blowtorch) to the outer end of the tag with the wire in place (as VicS says, make sure it is clean and then clean again). Apply some plumbing flux to the cable end and inside the tag before mating the cable to the tag - it is better than soldering flux. Apply heat, and as soon as the original solder starts to liquefy, add some more solder to fill the tag. Allow to cool naturally - don't plunge it into the water. After it has cooled to solid, but before it is completely cooled, wash any excess flux from the joint.

It is sometimes necessary to solder when crimping gear is not available, and connections must be made soonest.

 

[Bobobolinsky]

Hi a brand new one is only £4.50- £8.75 (depends on length, you can buy them from 50 to 300mm) from your local truck parts factors.

Robin

 

[Bilgediver]

The difference between a soldered joint and a crimped joint is that whereas a crimped connection is simply a mechanical, contact joint, a soldered joint is a molecular bond. The soldered connection being far more resilant to vibration and electrolytic corrosion failure. Maybe someone with more expertise than myself, a one-time electronics technician qualified to work on RN battleships, could correct me if this isn't so.

The reason for not soldering has nothing to do with the electrical properties.

When a thick multistrand wire is soldered in the way we are suggesting then the solder will form a sudden stress raising location at its surface.

This may not be a problem in this instance though to get it right the way Vic suggests is not for the inexperienced and faint hearted. The job is made difficult also as the lug has a vent hole in it through which the solder will escape unless plugged as the solder will be in the lug like a pool of mercury trying to escape.

Yes it can be done but might take the inexperienced a few goes before the plug of solder totally attains the correct temperature by which time the plastic will probaly have gone up in flames. Not even enough wire unless a big loop is formed to slip on heat shrink to use to cover the damage to the insulation....Yep Vic can no doubt do it and yes I have installed systems in this way but not where there may be vibration at the lug as in this case the wire will fail, IE lugs on the big terminal of starters.

 

[elton]

the solder will form a sudden stress raising location at its surface.

I don't know what that means

This may not be a problem in this instance though to get it right the way Vic suggests is not for the inexperienced and faint hearted. The job is made difficult also as the lug has a vent hole in it through which the solder will escape unless plugged as the solder will be in the lug like a pool of mercury trying to escape.

What does that matter? The intent is to wet the surfaces of the two components (the terminal and the wire) with solder and then to keep them in contact until the solder 'freezes'. There's no need to encase the components in a blob of solder.

Yes it can be done but might take the inexperienced a few goes before the plug of solder totally attains the correct temperature by which time the plastic will probaly have gone up in flames. Not even enough wire unless a big loop is formed to slip on heat shrink to use to cover the damage to the insulation....Yep Vic can no doubt do it and yes I have installed systems in this way but not where there may be vibration at the lug as in this case the wire will fail, IE lugs on the big terminal of starters.

A suitable heat sink will prevent damage to the insulation.

I'd agree that experience will produce a better joint, but an inexperieced solderer can detect a bad joint simply by looking for the symptoms as I described. This isn't necessarily so for a crimped union. Most failures of crimped connections that I've seen have been due to use of the incorrect tool and/or bad technique. A bad crimp is unlikely to appear so to a novice, whereas the symptoms of a badly soldered joint are pretty obvious.