I need to extend the power wires to my trolling motor by a few feet. The setup is all new wire but I had to route it a different way causing me to be short.  What's the most appropriate way?  Unfortunately the extension has to be on the top deck somewhere. I was leaning towards an Anderson SB connector.

 

That connector may do fine, but could get wet and be subject to corrosion on deck and could get kicked around as well.

 

Another alternative is to contact your trolling motor company and see if they have a longer power cable that you can go inside the trolling motor housing and maybe quickly swap them out easy enough. If not, I solder my wires. I don't like areas of potential failure when on the water.

 

Another issue with that particular type of connector- its used on wheelchairs as well for their batteries sometimes. And what I have seen with this particular connector is that the plastic housing breaks and splits apart. I removed this very same connector from my elderly mother's wheelchair for this same reason. I had one battery cutting in and out and it turned out to be one of these connectors breaking.

 

And as I recall the contacts or pressure for the contacts to keep the juice flowing depends on the plastic housing to remain intact. If it starts to break and split apart, your connections will begin to fail. So it might work fine at first, but over time this connector could become a problem.

 

If it were me, I would just cut off the wire and depending on size or gauge of the wire dictates solder overlap and thickness, but I would solder my wires.

 

Get some heat shrink. Thickest you can find for durability. Maybe even some heat glue on inside so after you do your connections you can cover them and seal them up somewhat.

 

And due to the large size of the wire, it takes some heat to do a thorough solder job. So locating a soldering iron with more than 50 watts up to 100 watts would make quick work of it and be sure to use rosin for good flow and adhesion.

 

I am not a fan of crimping power wires with this much current flowing through them. That's why I jump straight to soldering them and covering with heat shrink and be done with it.

 

This first image shows the "problem" connector that contacts depend on the plastic housing for making contact. This type of connector can heat up and cause more problems as it slowly fails. Exposing it to the elements will speed up that process.

 

This connector bad:

 

This next connector shows round contacts inside. These do not depend on the plastic housing for making electrical contacts.

 

This connector good:

 

If you choose to solder the wires, make sure you are very careful when stripping off the wire coating.

 

Some people unfamiliar with this invariably cut into the wire strands inside damaging and cutting through some of them reducing the wires overall current carrying capacity leading to heat buildup- if a problem.

 

And make sure to have a decent wire overlap at the solder connection of at least a half inch or so. Here is a video on soldering wires if of any value...

 

 

And its a good thing you said your wire is new. This means soldering to it will be easier. Older trolling motors, their wires get wet over time and the copper begins to corrode. Solder will not stick to it. So at the shop and at home I keep a small glass jar in the solder cabinet with muriatic acid in it that I - and the shop does as well- dip the corroded tips of the wire to be soldered into the acid for a few seconds to let it remove the corrosion back to clean copper wire. Rinse. And add rosin and then solder.

 

I also have a separate little glass jar of rosin on the bench as well to dip those wire tips into to help adhesion and flow. And yes, most solder comes with a rosin core, but I need those wires coated in it before the solder reaches the wire. As soon as it heats up enough the solder will flow like magic.

 

The solder technique for this large of a wire is to strip all 4 wires. Make sure copper is new and clean with no corrosion. If any corrosion is found, use weak acid to clean it. Rinse off acid. Apply external rosin to all 4 wires. Apply solder to all 4 wires separately. I then add in a little bit more solder to each of them so when two are brought together, the solder to make the cross connection is already on the wires. All I gotta do is melt them together.

 

I may or may not add extra solder. Depends on how thick that cross connection is. I like it to bulge out a little bit to be thicker rather than see that cross connection of solder thinner than the wires being connected. The solder is the transfer conductor so plenty needs to  be there. Too much tends to drop out by gravity and the wires will only hold approximately what they need to get the job done.

 

When soldering is finished, check for sharp points or edges and smooth them off and cover with heat shrink. Now you won't have to worry about it.

 

I would crimp the connection but make sure you do it right.   You should not be able to pull the wires apart with all your strength.  You need the right tools to do it right.  If you don't have a good crimper you need to borrow one or buy one.  A good hydraulic crimping tool can create a strong durable connection.

 

I do not like soldering for high current applications like a trolling motor.  Soldered connections have higher resistance and can crack in harsh environments.  

 

Here's good article on soldering vs crimping.

https://whma.org/soldering-vs-crimping-advantages-disadvantages/

 

The worst option is a plug.  I've known a couple of people that had a fire start on their boat.  Both were from trolling motor plugs.

Lots of I got here. As for it getting wet, I planned on putting it under here.  So chances of it getting directly wet are very low.

I would rather not rely just on soldering.  I have heard pros and cons to both. Unfortunately extending the trolling motor wires isn't an option because I have a plug up front.

 

https://www.wholesalemarine.com/ancor-6-gauge-marine-tinned-copper-heavy-duty-butt-connectors/

 

Would this be sufficient?  The trolling motor is 24v uses a 60amp fuse.  This would be a heck of a lot cheaper than the Anderson connectors.

 

 

1 hour ago, Tennessee Boy said:

would crimp the connection but make sure you do it right.

I have a friend who says you should always coat the exposed bare wire with Dielectric grease before you crimp it to reduce rust/oxidation. What do you think of that idea?

Are you running heavier gauge wire for your new trolling motor?  You mention having the plug up front for the trolling motor.  That aluminum plate the plug is in, comes off.  There are about 8 screws that hold it on.  You can access below the front deck a little with it off.  As you probably figured out the existing wiring is under the flotation foam, so none of it is moving.  

 

 

 

38 minutes ago, Bolar said:

Are you running heavier gauge wire for your new trolling motor?  You mention having the plug up front for the trolling motor.  That aluminum plate the plug is in, comes off.  There are about 8 screws that hold it on.  You can access below the front deck a little with it off.  As you probably figured out the existing wiring is under the flotation foam, so none of it is moving.  

 

 

 

Yes I am running heavier gauge wire for a new trolling motor.  I originally planned on going through the existing harness but they really secured that.  My current path is up through the motor battery cable grommet, then up the port gunwale to the grommet up front. I really don't want to drill into every compartment.

1 hour ago, Kirtley Howe said:

I have a friend who says you should always coat the exposed bare wire with Dielectric grease before you crimp it to reduce rust/oxidation. What do you think of that idea?

Good question.  I've heard some say that because Dielectric grease is not conducive, you should not put it between to conductors, only around the connection to keep moisture out after the connection is made.  Others say put it on battery terminals before you connect to them.  I personally do not use it on crimped connections or on metal surfaces that conduct electricity.   I feel like a well crimped connection with heat shrink wrap should be good enough.  I guess putting the grease on after crimping and before the heat shrink could help prevent oxidation but I've never done it.

Square bits are best for those screws.  Phillips tend to strip if really tight.  How do you plan to secure the cables to the underside of the gunnel?  There is not much there.  Not sure about the grommets. You can come off the battery directly, into a breaker, then under the bracing at the  back like you circled, under the gunnel, to the trolling motor itself.  If and where to plug in the trolling motor would be the next step.

5 hours ago, Tennessee Boy said:

I would crimp the connection but make sure you do it right.   

 

I do not like soldering for high current applications like a trolling motor.  Soldered connections have higher resistance and can crack in harsh environments.  

 

 

I have to disagree with some of this. No way a crimped connection has less resistance than a soldered connection. No way! Strongly disagree with this. Even artificial intelligence agrees with me on this one. See below. I included the AI text.

 

Solder bonds with the metal. It is bonded welded metal to metal to each and every strand in the wire. And with at least a half inch overlap that is a good amount of wire bonded to make sure high current can transfer without resistance.

 

Crimping is simply side by side touching and less contact surface area meaning all that current now has to travel through a smaller contact area which can only mean heat buildup. No bonding at all. No way a touching connection has less resistance than a soldered one.

 

And some crimps allow wire to slip out between the gaps in the crimped area of the connector. 

 

I also would say that solder reaches every wire strand. Crimping does not. Its only success at a connection is depending on external pressure to keep the contact. Not good for high current! That resistance will heat it up!

 

And yes, a wire coating for corrosion is a good idea. I use a red can recommended by military and used on ships and planes at sea with U.S. Navy. Best stuff on the market but I am leery of mentioning any brand names.

 

I also do not agree with solder connections can crack. If done right he won't have a problem. Ever. But if not done right, then sure maybe it can crack apart. Key is quality of work.

 

I mentioned I let my connection bulge a little bit. No way that solid blob of metal is gonna break.

 

Either idea will work. As I see it soldering is superior to crimping any day of the week. And if a crimped connection ever gets corroded or loose heat will build up there.

 

The last thing I would want in my boat is a crimped wiring harness. I want solid metal throughout.

 

Even when I crimp on various connectors, once crimped on, I then solder them. Zero issues. Solid is better than patched in my opinion. But to each their own!

 

The problem with soldering and crimping is that both require a learned skill. Most people do not have those skills and may not do it right leading to more problems.

 

And one thing I forgot to say earlier, is that depending on thickness of heat shrink, I would double it up just to be sure.

 

--------------------------------------------------------------

Artificial intelligence response to above claim:

 

Generally, soldered connections tend to have less resistance than crimped connections. This is because soldering creates a more continuous metal-to-metal bond, minimizing resistance, while crimping relies on pressure to create a connection which can sometimes be less conductive. 

 

Soldering:

The process of soldering involves melting a filler metal (solder) onto the wires being connected, creating a strong, low-resistance path for electrical current to flow. 

 

Crimping:

Crimping involves using a tool to compress a connector onto the wire, creating a mechanical bond. While a well-executed crimp can have low resistance, it's more prone to variations in resistance due to factors like proper crimp technique and potential for corrosion. 

 

Resistance Variations:

In high-vibration environments, soldered connections can be more prone to cracking, while crimped connections may be more durable. However, improper crimping can introduce higher resistance due to poor contact between the wire and connector. 

 

Practical Considerations:

While soldering can be more time-consuming, it's often preferred for applications where low resistance and a strong, reliable connection are paramount. Crimping is faster and can be more suitable for applications where speed is critical or where the connection is exposed to harsh environments

17 minutes ago, Bolar said:

Square bits are best for those screws.  Phillips tend to strip if really tight.  How do you plan to secure the cables to the underside of the gunnel?  There is not much there.  Not sure about the grommets. You can come off the battery directly, into a breaker, then under the bracing at the  back like you circled, under the gunnel, to the trolling motor itself.  If and where to plug in the trolling motor would be the next step.

 

Yeah I agree square bits work best. I've already had that off to install the new trolling motor plug.  As for securing the cables.. I have 1" plastic wire loom tubing that the cables are going into and you can jam it under the ledge. It's tight enough that it's not going anywhere.  I have 2 grommets on mine where the red circles are. They lead to under the decking.

I just called my old boss Greg McIntosh who is shop manager and decades-long trolling motor repairman for all major brands in central Florida. He has taught me how to rebuild them and customize them when I worked at the shop. 

 

I asked him point blank- 24v, 60a, need to extend 24 to maybe 30 inches. Crimp or solder? Which is best?

 

Greg: Solder, but crimp is fine as well as long as it is done right.

 

So both work, but myself and Greg at least agree on order of preference.

 

To the OP, it looks like my preference list is 1)new whole wire 2)solder 3)crimp 4)connector 5)move battery or trolling motor (kidding)

 

Someone might start with #3, then after connector fails resort to #2 as quick and easy, and when that has issues, either new whole wire which is still an option here, or solder.

 

All of us just try and offer up our best suggestions. Let us know how it goes.

4 hours ago, Zachary Guyach said:

Lots of I got here. As for it getting wet, I planned on putting it under here.  So chances of it getting directly wet are very low.

 

 

I would not worry about it getting wet. I would be thinking about corrosion on crimped connections and connectors and wire. If it is soldered well and right, then water is not even an issue. Water cannot get into a bonded welded metal connection.

 

We gotta remember we back our boat trailers down into the water with lights on and they keep working because of the low voltage situation. And none of us get shocked either.

 

So a 12 to 24 volt power run on deck with minimal water or moisture exposure, even to direct rain is not going to be an issue really. Shorting out and bad connections and corroded wire and crimps may be more to worry about. I would also use a corrosion inhibitor as someone suggested.

 

Anyone use the red spray can? It keeps our military going at sea. Helps anyway. Its mil spec'd.

If we're relying on AI.  Here is the ChatGPT answer using the Deep Dive function so it did about 10 minutes of research before generating the answer.

 

Question I asked:  

 

Is crimping or soldering  better for extending a 6 awg trolling motor wire with 60 amp circuit breaker?  The wire will be run along the gunwall on the deck of the boat. 

 

 

ChatGPT 4o Deep Research Report:  

Crimping vs. Soldering for Extending a 6 AWG Marine Wire

Introduction

 

Extending a trolling motor’s 6 AWG power cable (feeding a 60 amp circuit breaker) requires a robust, low-resistance connection that can withstand harsh marine conditions. The wire will run along the gunwale on the deck – an area exposed to vibration, moisture, and possibly salt spray. Two common methods for splicing heavy-gauge wires are crimping (using a butt splice connector) and soldering the joint. This report examines the pros and cons of crimping versus soldering for this specific marine application. Key factors include electrical performance, corrosion resistance, mechanical durability under vibration, and ease of installation. We also consider marine safety standards (like ABYC guidelines) and expert recommendations. A summary comparison table is provided, followed by a recommendation for the best approach in this scenario.

Electrical Performance

Crimped connections – when done properly – provide excellent electrical performance for high-current marine wiring. A quality crimp effectively “cold-welds” the wire to the connector, creating a gas-tight metal-to-metal bond with very low resistance . In fact, crimp terminals have been used for decades in critical applications (from automobiles to aircraft and warships) as a proven method for making low-resistance connections without solder . The crimp compresses the strands tightly, which breaks down surface oxides and ensures maximum contact area. As long as the correct size connector and a proper crimp tool are used, the result is a reliable, high-conductivity joint that can handle 60 A current with minimal voltage drop. By contrast, soldered connections can also be electrically sound if executed perfectly – solder itself is a good conductor and can create a solid bond between wires. However, soldering does not guarantee a low-resistance joint unless the technique is flawless. A common pitfall is the “cold solder” joint, where insufficient heat or poor solder flow leaves flux or gaps in the joint, causing high resistance . Such defects may not be immediately obvious but can lead to voltage drop, heating, or intermittent performance under heavy loads. Additionally, unlike a crimp which inherently forms a tight mechanical contact, a solder-only splice relies entirely on the solder for conductivity; if any part of that solder joint degrades, electrical performance suffers. In practice, marine experts assert that a properly crimped connection is equal or superior to solder in conductivity for DC wiring . For a trolling motor’s power cable, where stable voltage and current flow are critical, the consistency of a crimp is a safer bet. It’s telling that American Boat & Yacht Council (ABYC) standards prohibit solder as the sole means of connection, underscoring that a crimp or other mechanical fastening is the primary method to ensure a sound electrical and mechanical link . Overall, while both methods can theoretically yield low resistance, crimping provides more consistent electrical performance in the field, with less risk of hidden flaws.

 

Corrosion Resistance

 

Marine environments are notoriously corrosive due to moisture (often saltwater) and temperature swings. Crimped splices, if done with marine-grade materials, offer excellent corrosion resistance. High-quality marine crimp connectors are made of tinned copper, which resists corrosion, and often come with insulating sleeves that are nylon or polyolefin heat-shrink. When a crimped butt connector is sealed with adhesive-lined heat shrink tubing, it creates a waterproof barrier that keeps out salt and moisture . The result is a gas-tight, sealed connection – the crimping action itself makes the joint air-tight, and the adhesive heat shrink provides an extra layer of protection against water ingress and “green” copper oxidation . Many marine electricians also apply dielectric grease or corrosion-inhibiting spray on the crimp before shrinking for additional protection . In short, a properly executed crimp with tinned conductors and sealed insulation can survive for decades without significant corrosion.

 

Soldered joints, on the other hand, require more care to be made corrosion-resistant. The solder itself (typically a tin-lead or tin-silver alloy) is somewhat resistant to oxidation, but the process of soldering introduces flux – and any flux residues or voids can become a site for corrosion. If acid flux is used (never recommended for electrical work) it will definitelycause copper corrosion; even normal rosin flux, if not fully cleaned, can attract moisture or create mildly acidic residues over time . Moreover, solder tends to wick into the wire strands beyond the joint, under the insulation. If the joint is not perfectly sealed, moisture can creep along the soldered strands, leading to hidden corrosion further up the wire. A soldered splice must therefore be thoroughly sealed with heat-shrink tubing or self-fusing tape to keep out moisture. However, achieving a waterproof seal can be trickier because the soldered section is often irregular in shape and the process of soldering may have shrunk back some insulation. Some installers will coat a soldered connection in liquid electrical tape or epoxy-lined heat shrink to try to exclude water. Despite these measures, many experts warn that soldered connections are more prone to develop the “black wire” or verdigris corrosion over time if any gap in the seal occurs . Crimped joints inherently have less wicking of solder (since none is used) and usually a shorter exposed area, so they present less opportunity for capillary water intrusion. In summary, while both methods can be made corrosion-resistant with proper sealing, crimping with tinned materials and adhesive heat shrink is simpler and more foolproof. Soldered splices carry a higher risk if not meticulously sealed, and any mistake in sealing can lead to creeping corrosion that compromises the connection. For a wire run along a boat’s deck (gunwale), which will see occasional spray and humidity, the safer choice is a well-sealed crimp joint.

 

Mechanical Durability

 

Mechanical durability is often the decisive factor in the crimp vs. solder debate for marine use. Boats endure constant vibration from engines and waves, as well as flexing and movement of cables as the vessel moves. In this regard, crimped connections are far more robust. A proper crimp joint maintains the flexibility of the stranded wire right up to the edge of the connector. The strands are cold-welded inside the crimp barrel but immediately outside that barrel the wire remains flexible. This means the transition from stiff connector to flexible wire is very short and well-contained. Under vibration, a good crimp essentially moves with the wire – there is no extended “hard” section to concentrate stress. Pull-out strength of a correctly crimped 6 AWG butt splice is very high (meeting UL and MIL-spec tensile tests), so the wire is unlikely to pull out of the connector if crimped with the right tool . In contrast, soldering creates a hard, rigid section of wirewhere the solder wicks into the strands. The once-stranded wire becomes a solid rod for some distance past the joint. This “hard spot” is a known point of weakness – vibration and flex tend to concentrate at the boundary between the soldered (stiff) part and the still-stranded (flexible) part of the wire. Over time, flexing at this boundary can cause the copper strands to fatigue and break. As one marine wiring expert bluntly summarizes: “Solder creates a brittle point and will fail before a proper crimp every time” . Indeed, ABYC’s rationale for discouraging solder-only connections is precisely the risk of vibration-induced failure. ABYC Standard E-11 states: “Solder shall not be the sole means of mechanical connection in any circuit.” If solder is used, the connection must be “supported to withstand vibration” – meaning the joint should be secured so it cannot move . This is difficult to guarantee in practice. A soldered splice in a wire run along the gunwale would need to be strapped down tightly on both sides of the joint to prevent any flex at the joint. Even then, the stress riser still exists. By comparison, a crimped butt splice with strain relief is already mechanically stable and can further be secured with clamps, making it highly vibration-resistant without special precautions.

 

Another aspect of mechanical durability is how the connection behaves under extreme conditions, like an overload or high heat. If a heavy current overload or fault were to occur (for example, a short that briefly exceeds 60 A before the breaker trips), a soldered joint could potentially heat up to the solder’s melting point, especially if it had any pre-existing high resistance. Standard 60/40 solder melts around ~188 °C. In a worst-case scenario, a soldered splice could re-melt and come apart under severe overheating. As one boating forum member noted, “Over-current situations can cause solder to melt… you have the potential for a live wire flopping around that could start your boat burning” . While such extremes are hopefully rare (the circuit breaker should protect against sustained overloads), it’s an added failure mode to consider. A crimped connection has no such melting point concerns – the copper will handle very high temperatures (well beyond any safe level for surrounding insulation) without the connection itself failing.

 

In summary, crimping wins decisively on mechanical durability for marine wiring. It produces a strong, vibration-proof joint that retains wire flexibility, whereas soldering introduces a brittle segment prone to failure unless the joint is perfectly supported (and even then, the margin for error is slim). This is reflected in industry practice: marine and aviation technicians overwhelmingly use crimp or bolt connections, not solder, for wire splices due to the superior resilience .

 

Ease of Installation

 

When it comes to practical installation on a boat, crimping is generally faster and more straightforward, provided the proper tools are at hand. To crimp a 6 AWG cable splice, one needs an appropriately sized butt connector and a heavy-duty crimp tool. For large gauge wires, this typically means a ratcheting lug crimper, hydraulic crimper, or at least a hammer crimp tool, since the common hand crimpers for small terminals won’t handle 6 AWG . Acquiring or borrowing a good crimp tool is a one-time effort, and many marine supply stores offer crimping services or tool loans (West Marine, for example, often lets customers use their heavy crimper for battery lugs in-store ). Once you have the right tool, the process is quick: strip the wire, insert it into the butt splice, and compress the crimp until it’s fully tight. A properly crimped connector will hold the wire so firmly that you cannot pull it out by hand . After crimping, you simply heat the insulating tube to seal it. No curing time, no cleanup. The result is immediately strong and serviceable. In tight spaces on a boat, using a crimp tool can still be done – many crimp tools have long handles or hydraulic heads that can fit where a soldering iron might be awkward. The main “challenge” with crimping is ensuring you have the correct size connector and tool for the job, but manufacturers like Ancor make 6 AWG butt connectors readily available, and using the matching die on a crimper will yield a consistent result.

 

Soldering a heavy-gauge marine cable, by comparison, can be more demanding in practice. First, producing a good solder joint on 6 AWG wire requires a very high heat source – typically a large soldering iron (200+ watts) or a small torch. Applying sufficient heat to the joint without melting too much insulation is a delicate balance. On a rocking boat or outdoors (wind can cool the joint, and open flames are risky), this becomes even more challenging. It’s easy for an inexperienced person to underheat (resulting in a cold solder joint that looks dull and weak) or overheat (damaging insulation and charring the wire). As one marine how-to author notes, soldering on a boat “takes practice” and “requires a quality soldering iron”, especially to do it reliably in less-than-ideal conditions . In the context of splicing an in-place wire run, one might have to solder overhead or in a confined compartment, which is far from the ideal bench setup. Additionally, soldering thick wire is time-consuming – you must heat the copper mass evenly and feed solder until it wicks fully through the splice. Any movement of the joint before it cools can ruin the connection. Once soldered, you need to clean any flux residue (to avoid future corrosion) and then apply heat shrink or tape. Overall, soldering is a more skill-sensitive and time-consuming process than crimping for this size of cable.

 

In terms of convenience, crimping also has the edge: no electricity required (useful if the boat’s electrical system is a work in progress or if you’re docked without power), and no open flame. Soldering in a bilge or near fuel lines is obviously a hazard, whereas crimping is cold-work. The only scenario where soldering might seem “easier” is if one does not have the correct crimp tool at all – but given the importance of this connection, investing in the right tool or hiring a marine electrician to do the crimp is well worth it. In fact, some boaters who lack big crimpers will take their cables to a battery shop or marine service center for professional crimping rather than attempt an inadequate DIY crimp or a risky solder job. To summarize, for a one-off splice, crimping with the proper tool is generally easier and more foolproof. Soldering heavy cables is doable but requires much more know-how and care to get right, making it less practical for most boat owners in the field.

 

OK, the first boat picture would require a different approach compared to the second picture.

34 minutes ago, Tennessee Boy said:

If we're relying on AI.  Here is the ChatGPT answer using the Deep Dive function so it did about 10 minutes of research before generating the answer.

 

Question I asked:  

 

Is crimping or soldering  better for extending a 6 awg trolling motor wire with 60 amp circuit breaker?  The wire will be run along the gunwall on the deck of the boat. 

 

 

 

ChatGPT 4o Deep Research Report:  

Crimping vs. Soldering for Extending a 6 AWG Marine Wire

Introduction

 

Extending a trolling motor’s 6 AWG power cable (feeding a 60 amp circuit breaker) requires a robust, low-resistance connection that can withstand harsh marine conditions. The wire will run along the gunwale on the deck – an area exposed to vibration, moisture, and possibly salt spray. Two common methods for splicing heavy-gauge wires are crimping (using a butt splice connector) and soldering the joint. This report examines the pros and cons of crimping versus soldering for this specific marine application. Key factors include electrical performance, corrosion resistance, mechanical durability under vibration, and ease of installation. We also consider marine safety standards (like ABYC guidelines) and expert recommendations. A summary comparison table is provided, followed by a recommendation for the best approach in this scenario.

Electrical Performance

Crimped connections – when done properly – provide excellent electrical performance for high-current marine wiring. A quality crimp effectively “cold-welds” the wire to the connector, creating a gas-tight metal-to-metal bond with very low resistance . In fact, crimp terminals have been used for decades in critical applications (from automobiles to aircraft and warships) as a proven method for making low-resistance connections without solder . The crimp compresses the strands tightly, which breaks down surface oxides and ensures maximum contact area. As long as the correct size connector and a proper crimp tool are used, the result is a reliable, high-conductivity joint that can handle 60 A current with minimal voltage drop. By contrast, soldered connections can also be electrically sound if executed perfectly – solder itself is a good conductor and can create a solid bond between wires. However, soldering does not guarantee a low-resistance joint unless the technique is flawless. A common pitfall is the “cold solder” joint, where insufficient heat or poor solder flow leaves flux or gaps in the joint, causing high resistance . Such defects may not be immediately obvious but can lead to voltage drop, heating, or intermittent performance under heavy loads. Additionally, unlike a crimp which inherently forms a tight mechanical contact, a solder-only splice relies entirely on the solder for conductivity; if any part of that solder joint degrades, electrical performance suffers. In practice, marine experts assert that a properly crimped connection is equal or superior to solder in conductivity for DC wiring . For a trolling motor’s power cable, where stable voltage and current flow are critical, the consistency of a crimp is a safer bet. It’s telling that American Boat & Yacht Council (ABYC) standards prohibit solder as the sole means of connection, underscoring that a crimp or other mechanical fastening is the primary method to ensure a sound electrical and mechanical link . Overall, while both methods can theoretically yield low resistance, crimping provides more consistent electrical performance in the field, with less risk of hidden flaws.

 

Corrosion Resistance

 

Marine environments are notoriously corrosive due to moisture (often saltwater) and temperature swings. Crimped splices, if done with marine-grade materials, offer excellent corrosion resistance. High-quality marine crimp connectors are made of tinned copper, which resists corrosion, and often come with insulating sleeves that are nylon or polyolefin heat-shrink. When a crimped butt connector is sealed with adhesive-lined heat shrink tubing, it creates a waterproof barrier that keeps out salt and moisture . The result is a gas-tight, sealed connection – the crimping action itself makes the joint air-tight, and the adhesive heat shrink provides an extra layer of protection against water ingress and “green” copper oxidation . Many marine electricians also apply dielectric grease or corrosion-inhibiting spray on the crimp before shrinking for additional protection . In short, a properly executed crimp with tinned conductors and sealed insulation can survive for decades without significant corrosion.

 

Soldered joints, on the other hand, require more care to be made corrosion-resistant. The solder itself (typically a tin-lead or tin-silver alloy) is somewhat resistant to oxidation, but the process of soldering introduces flux – and any flux residues or voids can become a site for corrosion. If acid flux is used (never recommended for electrical work) it will definitelycause copper corrosion; even normal rosin flux, if not fully cleaned, can attract moisture or create mildly acidic residues over time . Moreover, solder tends to wick into the wire strands beyond the joint, under the insulation. If the joint is not perfectly sealed, moisture can creep along the soldered strands, leading to hidden corrosion further up the wire. A soldered splice must therefore be thoroughly sealed with heat-shrink tubing or self-fusing tape to keep out moisture. However, achieving a waterproof seal can be trickier because the soldered section is often irregular in shape and the process of soldering may have shrunk back some insulation. Some installers will coat a soldered connection in liquid electrical tape or epoxy-lined heat shrink to try to exclude water. Despite these measures, many experts warn that soldered connections are more prone to develop the “black wire” or verdigris corrosion over time if any gap in the seal occurs . Crimped joints inherently have less wicking of solder (since none is used) and usually a shorter exposed area, so they present less opportunity for capillary water intrusion. In summary, while both methods can be made corrosion-resistant with proper sealing, crimping with tinned materials and adhesive heat shrink is simpler and more foolproof. Soldered splices carry a higher risk if not meticulously sealed, and any mistake in sealing can lead to creeping corrosion that compromises the connection. For a wire run along a boat’s deck (gunwale), which will see occasional spray and humidity, the safer choice is a well-sealed crimp joint.

 

Mechanical Durability

 

Mechanical durability is often the decisive factor in the crimp vs. solder debate for marine use. Boats endure constant vibration from engines and waves, as well as flexing and movement of cables as the vessel moves. In this regard, crimped connections are far more robust. A proper crimp joint maintains the flexibility of the stranded wire right up to the edge of the connector. The strands are cold-welded inside the crimp barrel but immediately outside that barrel the wire remains flexible. This means the transition from stiff connector to flexible wire is very short and well-contained. Under vibration, a good crimp essentially moves with the wire – there is no extended “hard” section to concentrate stress. Pull-out strength of a correctly crimped 6 AWG butt splice is very high (meeting UL and MIL-spec tensile tests), so the wire is unlikely to pull out of the connector if crimped with the right tool . In contrast, soldering creates a hard, rigid section of wirewhere the solder wicks into the strands. The once-stranded wire becomes a solid rod for some distance past the joint. This “hard spot” is a known point of weakness – vibration and flex tend to concentrate at the boundary between the soldered (stiff) part and the still-stranded (flexible) part of the wire. Over time, flexing at this boundary can cause the copper strands to fatigue and break. As one marine wiring expert bluntly summarizes: “Solder creates a brittle point and will fail before a proper crimp every time” . Indeed, ABYC’s rationale for discouraging solder-only connections is precisely the risk of vibration-induced failure. ABYC Standard E-11 states: “Solder shall not be the sole means of mechanical connection in any circuit.” If solder is used, the connection must be “supported to withstand vibration” – meaning the joint should be secured so it cannot move . This is difficult to guarantee in practice. A soldered splice in a wire run along the gunwale would need to be strapped down tightly on both sides of the joint to prevent any flex at the joint. Even then, the stress riser still exists. By comparison, a crimped butt splice with strain relief is already mechanically stable and can further be secured with clamps, making it highly vibration-resistant without special precautions.

 

Another aspect of mechanical durability is how the connection behaves under extreme conditions, like an overload or high heat. If a heavy current overload or fault were to occur (for example, a short that briefly exceeds 60 A before the breaker trips), a soldered joint could potentially heat up to the solder’s melting point, especially if it had any pre-existing high resistance. Standard 60/40 solder melts around ~188 °C. In a worst-case scenario, a soldered splice could re-melt and come apart under severe overheating. As one boating forum member noted, “Over-current situations can cause solder to melt… you have the potential for a live wire flopping around that could start your boat burning” . While such extremes are hopefully rare (the circuit breaker should protect against sustained overloads), it’s an added failure mode to consider. A crimped connection has no such melting point concerns – the copper will handle very high temperatures (well beyond any safe level for surrounding insulation) without the connection itself failing.

 

In summary, crimping wins decisively on mechanical durability for marine wiring. It produces a strong, vibration-proof joint that retains wire flexibility, whereas soldering introduces a brittle segment prone to failure unless the joint is perfectly supported (and even then, the margin for error is slim). This is reflected in industry practice: marine and aviation technicians overwhelmingly use crimp or bolt connections, not solder, for wire splices due to the superior resilience .

 

Ease of Installation

 

When it comes to practical installation on a boat, crimping is generally faster and more straightforward, provided the proper tools are at hand. To crimp a 6 AWG cable splice, one needs an appropriately sized butt connector and a heavy-duty crimp tool. For large gauge wires, this typically means a ratcheting lug crimper, hydraulic crimper, or at least a hammer crimp tool, since the common hand crimpers for small terminals won’t handle 6 AWG . Acquiring or borrowing a good crimp tool is a one-time effort, and many marine supply stores offer crimping services or tool loans (West Marine, for example, often lets customers use their heavy crimper for battery lugs in-store ). Once you have the right tool, the process is quick: strip the wire, insert it into the butt splice, and compress the crimp until it’s fully tight. A properly crimped connector will hold the wire so firmly that you cannot pull it out by hand . After crimping, you simply heat the insulating tube to seal it. No curing time, no cleanup. The result is immediately strong and serviceable. In tight spaces on a boat, using a crimp tool can still be done – many crimp tools have long handles or hydraulic heads that can fit where a soldering iron might be awkward. The main “challenge” with crimping is ensuring you have the correct size connector and tool for the job, but manufacturers like Ancor make 6 AWG butt connectors readily available, and using the matching die on a crimper will yield a consistent result.

 

Soldering a heavy-gauge marine cable, by comparison, can be more demanding in practice. First, producing a good solder joint on 6 AWG wire requires a very high heat source – typically a large soldering iron (200+ watts) or a small torch. Applying sufficient heat to the joint without melting too much insulation is a delicate balance. On a rocking boat or outdoors (wind can cool the joint, and open flames are risky), this becomes even more challenging. It’s easy for an inexperienced person to underheat (resulting in a cold solder joint that looks dull and weak) or overheat (damaging insulation and charring the wire). As one marine how-to author notes, soldering on a boat “takes practice” and “requires a quality soldering iron”, especially to do it reliably in less-than-ideal conditions . In the context of splicing an in-place wire run, one might have to solder overhead or in a confined compartment, which is far from the ideal bench setup. Additionally, soldering thick wire is time-consuming – you must heat the copper mass evenly and feed solder until it wicks fully through the splice. Any movement of the joint before it cools can ruin the connection. Once soldered, you need to clean any flux residue (to avoid future corrosion) and then apply heat shrink or tape. Overall, soldering is a more skill-sensitive and time-consuming process than crimping for this size of cable.

 

In terms of convenience, crimping also has the edge: no electricity required (useful if the boat’s electrical system is a work in progress or if you’re docked without power), and no open flame. Soldering in a bilge or near fuel lines is obviously a hazard, whereas crimping is cold-work. The only scenario where soldering might seem “easier” is if one does not have the correct crimp tool at all – but given the importance of this connection, investing in the right tool or hiring a marine electrician to do the crimp is well worth it. In fact, some boaters who lack big crimpers will take their cables to a battery shop or marine service center for professional crimping rather than attempt an inadequate DIY crimp or a risky solder job. To summarize, for a one-off splice, crimping with the proper tool is generally easier and more foolproof. Soldering heavy cables is doable but requires much more know-how and care to get right, making it less practical for most boat owners in the field.

 

Ok. More words than I used. You win!

 

Let the reader decide...

 

But your point is well taken. AI don't know anything beyond what it is programmed to know!

 

If you use that popular G search thingy, its AI votes same as California does! I sort of figured if it was artificial intelligence it would be smart to vote the right way and provide answers not aligning to a particular side of the aisle? Maybe its not intelligent enough yet? Let the AI baby grow up some. Our future is in deep trouble now! AI should be our best friend but sci-fi movies suggest otherwise.

 

I guess I should learn my lesson right here and not use AI any more. 

1 hour ago, Tennessee Boy said:

As long as the correct size connector and a proper crimp tool are used, the result is a reliable, high-conductivity joint that can handle 60 A current with minimal voltage drop. By contrast, soldered connections can also be electrically sound if executed perfectly – solder itself is a good conductor and can create a solid bond between wires. However, soldering does not guarantee a low-resistance joint unless the technique is flawless.

 

 stable voltage and current flow are critical, the consistency of a crimp is a safer bet. It’s telling that American Boat & Yacht Council (ABYC) standards prohibit solder as the sole means of connection, underscoring that a crimp or other mechanical fastening is the primary method to ensure a sound electrical and mechanical link . Overall, while both methods can theoretically yield low resistance, crimping provides more consistent electrical performance in the field, with less risk of hidden flaws.

 

Overall, soldering is a more skill-sensitive and time-consuming process than crimping for this size of cable.

 

 Soldering heavy cables is doable but requires much more know-how and care to get right, making it less practical for most boat owners in the field.

 

Not gonna debate which is better. What you posted makes it pretty clear that a crimped connection can keep up with solder, and solder has pitfalls which I would like to address 2 things in the above that is if'y.

 

1) I can use a higher temp or different composite solder than the easy to melt version. So if that connection can heat up and melt solder, it can be mitigated to some degree. But this would tend to indicate to me the wire conductor itself is not up to snuff and maybe should be a larger gauge.

 

"High-temperature solders are designed to maintain their structural integrity at elevated temperatures, unlike standard solders that might melt or degrade. These solders are often used in applications where components are exposed to high heat, such as in automotive, aerospace, and power electronics. They typically have a higher melting point and can withstand temperatures above 260°C."

 

But concerning those crimped connections...

 

When I solder good wire is side by side undamaged. But when inexperienced people crimp you know cranking it down as hard as possible is always better right?

 

2) When this happens I can't tell you how many crimps I have seen where they squeezed nearly through the wire itself. Many who crimp do damage the wire strands. And when those are compressed, knicked, etc. the wire breaks off right out of the end of crimp because of that over cranking damage. This damage also reduces current capacity across the connection.

 

"Improperly performed crimping can damage wires, leading to reduced current capacity and potential performance issues. Damaged strands, incorrect crimp height, and poor contact can all increase resistance and heat, ultimately affecting the wire's ability to carry current safely. 

Stripping tools or excessive crimping force can damage or sever individual wire strands. This reduces the overall cross-sectional area of the conductor, increasing resistance and limiting the current flow."

 

Both crimping and soldering have to be done right. I often crimp and then solder but never crimp only.

 

To each their own. Both work if done right. Key is flawless execution of either.

 

I gotta add in we have all made good suggestions here, but the real downfall to all of this is in the hands of the reader(s) who may not have good tool skills.

 

Professionals can make it sound easy, but you ever watch a rookie with a soldering iron? I can see why crimping is preferred is because of ease as mentioned, but wire damage and little to no skill undermine all suggestions.

 

Maybe the best one is to seek a professional to get it done right.

There is a lot of great info in this thread.  Thank you for all who posted. I think what I am going to do for now is wire the trolling motor directly to the cables from the battery since it has 5ft leads.  I want to see how hot the cables get since 6 gauge is technically too small for a 20ft length (24v 80lb).  

On 7/26/2025 at 4:53 AM, FloridaFishinFool said:

 

 

 

This connector bad:

 

 

 

 

 

(unless I am missing your point) your good vs bad connectors are the same connectors.   the round is where the actual wires/conductors go.  they are round shaped now, but once you crimp them - no longer round.

 

the flat side is where they mate up with the other connector flat side make the solid contact.  

 

OP

 

this is an Anderson SC connector and is what I am using.  

 

@Zachary Guyach I think the Anderson route will work for what you are doing, but there are some limitations.  first crimping a SB50 connector - the round end of above - is no joke.  they use a special crimping tool that costs a lot of money.   I used a dulled out bolt cutter super slow and carefully and I got a solid crimp.   the connection is solid!!  second, the Anderson SD50 connector is bulky.  if flies around like a mace in my kayak and is effective as a grappling hook.  it hooks on everything.  if you can tuck it away, good.  the connectors are also kinda expensive.  especially buying in 1-2 as we need.  and you purchase the inserts separately.  buy extras, trust me.  

 

look at Newport Vessels "extension" kit.  comes with a block that you simply bolt two connectors together with brass hardware.  easy peasy, and you can screw that block to a bulkhead easily.   

here are the posts for the insides of the Anderson SD.  you can see the round side and the flat side.  @FloridaFishinFool I do believe your good vs bad are the same connectors - just opposite sides. 

 

oh..there are clones, copies, fakes.  buy the legit ones,  way better than the ones my friend bought.  mine click together with authority.

 

 

Double uni and electrical tape 😁

Since a lot of these responses are so long, I quit reading so I'm just going to give my opinion.  My experience consists of having a degree in electronics, over 50 years working experience in electronics and over 20 years' experience in battery powered material handling equipment and industrial equipment using batteries that weigh as much as a ton and operating at over 600 amps under all sorts of conditions.  By far the Anderson SB connectors is the one normally used.  Also understand, the connector number SB50, SB75, SB350 etc is not the amp rating of the connector, it is the amp load the connector can be unplugged at without causing arcing of the contacts. The SB50 can handle a whole lot more than 50 amps without causing resistance and heating up.   I have always used nothing but SB50's on my TMs connectors.  Back in the days they used to put those three prong AC plugs in the bow for 12/24 uses, and for plugging in the charger.  Since I always ran 24VDC, the first thing I did with one of those is take it out and install an SB50.  And yes, like everything now days there are cheap fakes, so buy from a reputable source.

 

As for dielectric grease on them, while I religiously use it on small, low current connectors, I've never seen a need for it on the Anderson connectors.

 

Installing any connector on a DC circuit, you should always make a good mechanical connection before soldering, so crimp with a proper crimping tool before you solder and always solder after you crimp any connections that's going to be exposed to the elements and use a heat shrink that is self-sealing.  Just squeezing a connector down is not a crimp. On large terminals like the SB connectors as a minimum use something like these. Hammer Lug Indent Crimper Tool, Battery Cable Crimping Tool, Wire Terminal Crimping Tool For 8 To 4/0 American Gauge Wire And Cable (AWG) - Search Shopping

 

 

9 hours ago, Darth-Baiter said:

  

here are the posts for the insides of the Anderson SD.  you can see the round side and the flat side.  @FloridaFishinFool I do believe your good vs bad are the same connectors - just opposite sides. 

 

oh..there are clones, copies, fakes.  buy the legit ones,  way better than the ones my friend bought.  mine click together with authority.

 

 

I used the wrong photo for an example. My point was the connector I consider bad depends on its plastic housing for making electrical contact. If the plastic cracks, the electrical connection will fall apart as well. I have already removed this same connector from a wheelchair for just this very reason. It works fine as long as plastic housing stays intact.

 

There is another type of connector that is not dependent on the plastic housing to make the electrical connection. 

 

These little beauties here are 150 amp. 6 metal on metal pressure contacts. The above connector has 1 contact and uses plastic to be the counter force holding contacts together.

 

In my opinion a "good" connector like this one is far better, and if plastic breaks out in the middle of the lake you won't be without electricity.

 

Bite the bullet and use 2’ longer wire, splices in boats isn’t a good idea!
Tom

22 hours ago, Zachary Guyach said:

There is a lot of great info in this thread.  Thank you for all who posted. I think what I am going to do for now is wire the trolling motor directly to the cables from the battery since it has 5ft leads.  I want to see how hot the cables get since 6 gauge is technically too small for a 20ft length (24v 80lb).  

I disagree that 6 gauge is too small.  I have a 24v 80lb Ultrex.  It draws 41 amps at max speed.  Using standard resistance values for 6 gauge wire found on the internet you would see a 0.65 volt drop in 40 feet of wire (battery to TM and back) at 41 amps.  That's 2.7% if all of my math is correct.  

 

At 60 amps it would be 0.95 volt drop or 3.95%

 

3% drop is the standard for critical application and 10% drop for non critical.  My trolling motor is  below 5 (Max speed 10) 95% of the time and below 3 80% of the time.  It pulls 2.5 amps on 3 speed.  Voltage drop is dependent on amperage so at 2.5 amps the drop is like 0.16%

 

6 gauge wire is pretty standard for trolling motors in bass boats.  I think you're good with 6 gauge.

I have to disagree, 6 ga is too small for most 24V applications with larger TM's.  

Hopefully someone is not running cable small enough to feel it getting warm, but a lot of people run cable too small, and it cause a voltage drop.  On a bow mount 40 - 50amp TM where there's 20' or less of cable, I would run 4ga fine strand marine/battery cable.  However, I usually go ahead and install 2 gauge welding cable for any motor pulling close to 50 amps.  It ain't cheap, but it's the right way to do it and you only have to do it once.   Understand, I said 24VDC, 36VDC  6 gauge would be fine.

If you want to see if the cable is large enough, with TM running on max in the water take, use a good digital volt meter and measure the battery voltage at the batteries, and then at the TM connector.  If the readings are within 3% of each other then the cable is considered large enough. Any more than 3% and you need to use larger cable.  

 

@Way2slow are you saying a 4% voltage drop is dangerous?