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


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)


  1. Thank you.

  2. This is the page that says to put petroleum jelly directly on the terminal posts: I’ve seen that advice elsewhere, too.

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

  3. 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. 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. 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. 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.

  7. I agree with Vincent; if the grease is not conductive, you should only apply it after connecting to the post. If you applied a non-conductive grease to the post prior to connecting the wiring, it will form an insulation layer between the electric connections.
    The idea is to insulate the terminals from the air moisture, which will create the the salt and corrosion later on, and that could be achieved by applying the grease after making a good electric connection (by connecting a clean terminal to a clean post).
    Electrical Power Engineer

  8. What about flammability of these greases? Are the fiber washers flame retardant? We handle these on production bases and wonder if they should be stored in a flame-proof cabinet?

  9. The conductivity of grease is irrelevant when you’re dealing with the 100 + Amp cranking current. All electrical joints – mains or automotive – require clean, dry mating surfaces for low resistance. Putting any sort of grease on terminals before connection will increase it. It’s often not explained clearly by people who should know better – even manufacturers.

    Clean the terminals and clamps as people describe, secure the clamp, then apply grease all over the joint to keep air and moisture out. The grease can’t penetrate between the two conductive surfaces if they’re firmly secured.

  10. I’ve found the best way to care for post terminal batteries is to pour the baking soda solution on the terminals and battery top, wait until it quits foaming, then rinse with hot water. Next, disconnect the ground terminal (neg.), then the positive. Since good terminal and cable end cleaner tools are not available anymore, I use an old pocketknife to carefully ream the cable ends to shiny metal. I then use a strip of shop cloth to clean the posts. Once everything is back together, I spray battery terminal protector on each connection. Lastly, I clean the top of the battery with window cleaner and a paper towel.

  11. Hello all. After reading the posts, it came back to me; when I had older cars and corrosion on the battery terminals, I used Coke (the soda) and it would dissolve the acid corrosion and help in the cleaning of the posts and cables. I also remember using boric acid for the same cleaning. Coke is good also for cleaning out battery compartments of items that use reg. batteries e.g. AA, C, D… Just use it sparingly and don’t drown the compartments. Also, after cleaning the car battery posts, I would coat the terminals as well as the attaching the ends of the cables with either Vaseline (don’t remember if it was clear or petroleum) or lithium grease. One other thing comes to mind and that is I think I used to check the other ends of the cables (those that were attached to a “negative ground” and those that were attached to their “positive source” for corrosion build-up. Never had any problems after that. Hope this imparts some useful information. HAPPY HOLIDAYS!

  12. I have been using the grease that electricians use on aluminum wire. It’s a conductive grease that keeps corrosion away from aluminum wire. My ex-brother-in-law (an electrical contractor) told him to use it on battery cables that they would stay clean and it helps contact. It can be bought at any place that sells electric wire.

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