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Replace Battery Cable

Product Guide & Information

Learn how to replace battery cable. Understand the benefits of soldering and crimping of the battery cable terminations.
replace battery cable

Replace Battery Cable

Whenever something goes wrong with any electric machine, it is a problem with the current. Either electric power is not getting to where you want it to go or, if it is, it is not in the right amounts [is this always the case?]. The current can be too high, too low, going to the wrong places, or there is no current. There are different ways these problems come up, but as far as wiring goes you will need to check both the cables themselves and their connections. Sometimes just cleaning the connections is enough, so you may not actually need to replace battery cable. If both the cables and their connections appear to be in good working order, then the problem is probably with the machine components themselves. View more information on car battery wires durability, to see if you need to replace your battery cable.

Safety first

When you are going to check or replace battery cable in your automotive vehicle, please take the following precautions:

Always wear safety glasses - Harmful chemicals can get into your eyes while brushing off dirt and corrosion from your connections, or when you forget and rub your eyes without washing your hands.

Wear gloves - If it were just oil and grease, bare hands would work, but working around automotive lead-acid batteries means you will likely be exposed to dangerous chemicals. At least wear some thin nitrile or latex gloves, especially when working around batteries that use harmful chemicals for the reactions that strip electrons from the metal core. If you are working with big trucks or other equipment that has more space, then using thicker gloves that offer more protection is more of an option.

replace battery cable

Wash your hands thoroughly - Many mechanics choose not to wear gloves because they like having their hands and fingers free to feel around under the hood. For small cars, getting fingers into tight spaces is often an issue as well (e.g. tightening a screw or bolt), and bulky gloves that dull tactile senses in your hands can get in the way. However, even mechanics who refuse to wear gloves know that you need to wash your hands thoroughly, often with special chemical cleaners.

Do not work near flames or sparks - Automotive lead-acid batteries produce hydrogen gas, which is explosive.

Always disconnect the negative terminal of the battery first and connect it last - This has to do with the direction DC electric currents flow through metal. Electrons flow from the negative to the positive end (though conventional notation shows an imaginary current going from positive to negative). When you are about to replace battery cable, if your wrench happens to touch a metal part of the car or battery with the negative ("ground") cable still connected, current may travel through whatever the other end of the wrench is touching. This will also create sparks that may ignite the hydrogen gas in the battery.

How often should I check my connections?

If you know what to look for, then a great time to check the electrical connections in your car or truck is during every or every other oil change, since you can check your cables and connections while waiting for the oil to drain.

How do I replace battery cable?

First determine if you need to replace the cable or if it is enough to clean the connections.

If you find that you really do need to replace battery cable because of damages, undersizing, or you just prefer using a different cable:

Should I solder or crimp my connections?

replace battery cable crimp

Crimping is favored as the standard form of connection in the automotive, aviation, and marine industries. However, people who work a lot with circuit boards and other small electronic devices favor and use soldered connections as the standard. Below is information about crimping and soldering to help you understand what each method is, the tools you will need, and their advantages and disadvantages.

Soldered terminals are not really used for cables in automotives because of their poor mechanical properties. Solder, which essentially acts like a strong glue, is more vulnerable to damage from high noise, vibrations, and harshness (NVH) applications. Soldering is more common on circuit boards and other small "light service" wiring where mechanical stresses are not as great as in an automotive engine.

Each method has its advantages and disadvantages. Both methods can work well or quickly fail depending on the quality of the connection. Regardless of the method, what matters for any electrical joint is that there is a secure mechanical connection that has protection against damage and corrosion with as large a contact area as possible between the (copper) conductor and the connecting terminal or lug. The joints where connections occur are often weak points in a circuit. Secure mechanical connections provide strain and stress relief from vibrations. Good insulation and coatings protect against corrosion and dirt, and having a larger contact area reduces electrical resistance.

There is also the connection between the cable end (i.e. terminal or lug) and whatever it is connected to (e.g. car frame, battery post, or other device), so make sure to buy the right terminals that are corrosion resistant too. Make sure your connections are secure, clean, and tight. Sometimes vibrations will loosen connections, especially if they are poor solder connections (e.g. the "cold joint").

Crimp first and solder

This method is meant to provide the strong and sturdy electrical connection of a crimp with corrosion protection from applying the thinnest layer of solder, also known as "tinning." Adding heat shrink tubing or tape finishes the insulation. However, because your cable will most likely be stranded, the solder will seep into the strands and make the soldered points more brittle. Thus, make sure to only apply a very thin layer of solder to "tin" the wires, and fit some sort of protective sleeve on them after. The purpose of soldering in this case is only to provide corrosion protection.


Crimping Soldering
Advantages
  • A good crimp will be a "cold" weld, and welds are stronger than solders.
  • Mechanical connection as strong as the metals being crimped.
  • Little added resistance since properly crimped joints will be welded together.
  • No heat needed. In fact, you can crimp in the cold.
  • Few safety issues.
  • Easy to perform. The hardest part is selecting the right terminals and crimping tool.
  • No clean up needed.
  • Can be done with low levels of surface oxidation because crimping should cold weld surfaces together and break past thin surface oxidation. Of course, clean and oxidation free metal surfaces improve any connection (crimp or solder).
  • Manual crimpers can be used in circumstances where soldering may not be an option (e.g. no electricity available).
Advantages
  • Superior protection against corrosion.
  • Solder itself conducts electricity, though its resistance is higher than copper.
  • Can be used regardless of wire gauge.
  • Favored for use in very small connections, such as on circuit boards.
  • Reversible. If you make a mistake, there is a desoldering tool that lets you remove the solder and start over.
Disadvantages
  • Little to no protection against corrosion. (Using heat shrink tubing or tape helps)
  • Everything depends on selecting a quality crimper that suits the kind of terminals and cables you are using (e.g. open vs closed barrel, wire gauge, insulated or uninsulated, etc.). Remember, a good crimp will actually weld the metals together.
  • If you make a mistake and get a bad crimp, you will have to cut off the cable end, discard it along with the used terminal, and try again with the now shortened cable. Thus, you want to be sure to have a longer cable in case you get a bad crimp.
Disadvantages
  • Heat from the soldering iron can damage components around the joint.
  • Connection is only as strong as the solder.
  • Solder has a lower melting point and higher resistance than copper.
  • More brittle mechanical connection.
  • Need to make sure the metal surfaces being soldered are clean.
  • Solder will not work if there is any layer of oxidation on the metal surfaces because oxidation prevents contact between the solder and the metal. This is why solder wire has flux cores (rosin or acid) to help prevent oxidation caused by the hot soldering iron itself.

Call us at 877.474.8209 to speak with an application engineer about your project.