Is it Safe to Put Grease on Your Car Battery’s Electrical Terminals?

batteryterminal

Paul asked: Do you really put grease on a clean battery post before attaching the cable? In the Cleaning a Car Battery section, it says to prevent corrosion, you should put grease on the clean terminal post before you reattach the cable. Won’t this prevent a good electrical connection?


The grease that should be applied is white lithium grease. It is readily available at automotive stores. It will not interfere with the electrical connection, but will help prevent future corrosion by displacing the air in the surrounding space.

The idea is to apply the grease to the terminal after you have connected and tightened the battery cable. This will create a layer of grease between the conducting surfaces and the surrounding air and moisture, and thus, prevent corrosion. Always apply it to a clean terminal for best results.

It is also wise to install a pair of felt washers underneath the terminals. These washers are available in automotive stores, right near the batteries. The help prevent high-resistance shorts across the battery case (when batteries get really dirty, the layer of oil and dirt will sometimes be conductive enough to connect the two terminals electrically)

Comments

  1. Gail says:

    Thank you.

  2. Tye Z says:

    This is the page that says to put petroleum jelly directly on the terminal posts: http://www.howtocleanstuff.net/how-to-clean-car-battery-terminals/. I’ve seen that advice elsewhere, too.

    It’s discouraging to see conflicting advice on this site. Which is correct?

  3. Melanie says:

    Tye,
    Both articles agree that grease should be applied directly on the terminal posts. Petroleum jelly is often used for cuts and wounds because it acts as a seal against oxidation, which is the same reason that people put grease on battery terminals. Some people prefer to use petroleum jelly simply because they have already have it on hand, it is less expensive than lithium grease and they can use it for other purposes. Either product will complete the task of protecting your car battery from corrosion, however white lithium grease is the recommended product that is used by professionals.

    Source: WiseGeek – What is Petroleum Jelly?
    Source: Wikipedia – Lithium soap
    Source: Reader’s Digest – 5 Car Battery Tips and Tricks

  4. Tye Z says:

    Thanks for that info. This article says to do it “after you have connected and tightened the battery cable”, but the other says to do it before. Does it matter?

  5. Melanie says:

    Great catch, Tye! I believe that sentence is written correctly since the following sentence agrees, “between the conducting surfaces and the surrounding air and moisture.” It is the corrosion between the terminal and cable that will interfere with the battery’s efficiency, but either process (applying it with cables on or off) should accomplish the task of preventing corrosion to that area. Strictly corrosion speaking, applying it with the cable attached is likely more effective because it would protect all of the exposed metal, rather than just the connection areas.
    However, there is the also argument that the surfaces of the terminal (post) and cable connector are not completely smooth, so applying the grease between them would allow current to flow more efficiently because the grease would get into all the grooves of the metals and therefore increase the conductive surface area.
    Regardless, the articles do disagree on the process, so I will send a request for the resident Mr. Clean to review all this.

    Source: WiseGeek – How to Clean Car Battery Terminals
    Source: HowCast – How to Treat and Prevent Car Battery Corrosion Problems
    Source: Stackexchange – How do I apply dielectric grease to my battery?

  6. Vincent says:

    Seems to me, unless the product has a conductive component, it will act as a resistance component if applied to the two conductive surfaces prior to connecting the cable on the terminal.

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