Battery Cable Repair

How To Repair A Battery Cable

When repairing a battery cable it is best to remove the cable from the vehicle. If you have the battery lug crimper you can perform an on vehicle service which in some situations can be very helpful. This tutorial will show you a way to do the repair without a battery lug crimper, but requires removal of the battery cable.lugcrimper

After removal of the battery cable, cut back as much cable needed to rid of the corrosion. If you leave ANY of the corrosion it will spread like cancer and you will eventually replace the cable anyways! You can also get bulk battery cable for replacement or even use a  battery lug butt connector to add and extension to cable if needed after cutting back the corrosion. Regardless of what you have to do cut back as much cable as needed to completely rid of thebrokenterminal corrosion also known as sulfating. This particular repair we will only be replacing the negative battery cable end, positive and negative battery terminals. On Subaru’s  the negative battery terminal is part of the battery cable and it is cracked. Subaru will only sell the battery cable as a positive and negative cable assembly and could cost you over $100.00 and this repair will cost under $20.00.

I am going to use the bench vise to pres the battery lug onto the cable. Make sure you have a good solid crimp. I recommend to solder the cable to the lug after crimping. A small propane torch and some solder should work fine. Finally you use a heat gun and heat shrink the cable to give it a good insulated seal. I have had best luck using factory Subaru positive terminals and factory Toyota negative terminals. The positive and negative battery terminal posts are different size and are not interchangeable unless you’re using those universal battery terminals win which I do not recommend. Any other style battery terminal with a bolt on style lug will work.

You have know have repaired the cable and it’s important to clean all corrosion off battery or it will just spread to the cable again. Another thing to keep in mind is sometime when testing a battery it will pass all test and perform how it is supposed to but the battery is old and sulfating. In this situation if you don’t replace the battery it will ruin all your new components over a prolonged period of time. So if you cannot afford a new battery right away it’s ok just keep that in mind. When cleaning battery I always use baking soda and water. They sell different battery cleaning solutions, baking soda and water works fine for me. Always clean the battery surface and hold down along with servicing the terminals. If hold down is corroded through the paint clean and re-paint or replace. The corrosion going through the hold down is known as surface discharge. The battery voltage is actually finding a path to ground through the dirty battery surface, battery hold down and fasteners. There is a way to test the battery surface discharge but I am not going into that because I feel that it’s an irrelevant test. Just remember to keep the surface of the battery clean and you should be fine.

The last part of this service will be to seal the battery terminals from corrosion. They have a lot of different type of battery cable/terminal sealant through aerosol cans and what not. They usually claim to fight and stop corrosion better but in my opinion are inefficient. You can also get felt looking battery sealing washers which are helpful. For me, over experience of using all these different types of sealers I have learned that using die-electric grease is the cheapest and the MOST effective way to seal the battery terminals and cable ends. Go to blog post electrical system testing for specifics on testing your battery and battery cable connections. Thank you again and hope you learned something from this….

This post was written by: Martin Hand

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Martin Hand

About Martin Hand

ASE Certified L1 Advanced Mastertech. Martin Hand has over 15 years experience in Asian and European Import Auto Repair. Specializing in electrical diagnosis, engine performance, AT/MT transmission repair/rebuild. Martin is also pursuing a degree in Computers Science & Information Systems starting at Portland Community College while he plans to transfer to OIT. Certified in Java application level programming, experienced with other languages such as PHP, Ruby, JavaScript and Swift. Martin has future plans of automotive diagnostic software development.

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