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How to clean battery contacts?


Battery contacts and vehicle battery terminals are exposed to many factors than can cause patination, make them dirty or rust over. Those factors include adverse weather conditions and unsealing of battery cells that causes them to leak substances which then patinate contacts and terminals. Learn how to clean vehicle battery terminals and battery contacts.

Keep reading to learn:

Why do terminals and contacts patinate and corrode?

Most naturally occurring metals are oxidised ore—they try to return to this state of permanent oxidation when used in their metallic state. This process is called corrosion. What’s interesting, the more energy is used during the technological process of turning ore (persistent bound form) into its metallic form (unstable free state), the more easily and quickly it will corrode when used.

Corrosion affects surfaces of metallic materials. The process requires electrolyte (moisture, water with dissolved gases and chemical compounds), and a depolariser (oxygen). Electrolyte and depolariser are fundamental external factors that cause corrosion.

The corrosion process is also determined by a metal’s chemical composition, state of its surface, and stress formed during heat treating—all of these are internal factors. Every material’s internal corrosion factors are determined mostly by crystal structure, containing atoms of elements with specific properties and valence electron numbers. Susceptibility to corrosion is also determined by the purity of a material—the less pure the alloy and the lower its electrochemical potential, the higher the probability of corrosion.

Patination affects both non-galvanised and galvanised elements that are not protected against zinc oxidation. Zinc is highly reactive in acidic and alkaline environments. Unprotected zinc surfaces coming into contact with electrolyte are affected by the so-called white rust (wet storage stain). In normal weather conditions, zinc creates zinc oxide, zinc carbonate, and zinc hydroxide that manifest as easy-to-clean white build-up. This build-up prevents corrosion of metal elements, but also dramatically reduces their electrical conductance.

Build-up on vehicle battery terminals may also be caused by unsealing of the battery or its sulfation—the build-up is slightly darker in those cases. Patination can also become an issue when voltage regulator gets damaged, causing overcharging of battery, boiling of electrolyte, and increased emission of gases that react with terminals and, consequently, patinates them. If that happens, you need to properly clean the vehicle battery terminals.

How to clean vehicle battery terminals?

Prior to cleaning battery terminals, they have to be disconnected from the source of power. If the terminals are heavily patinated, you can use a soft wire brush – like the PG MINI 496.82, or a block of sandpaper or soft scouring pad, and a soft cloth. Also, baking soda can be used for cleaning contacts. However, you have to remember to remove the remains from the surface. In addition, strong mechanical abrasion of the surface of contacts and terminals may result in excessive removal of the surface material, leading to an enlargement of the terminal holes or reduction of the diameter of battery posts, which may limit the surface of contact and compromise the correct flow of electricity.

How to clean vehicle battery terminals from hard-to-remove build-up? You can use an IPA isopropyl alcohol – e.g. AG TERMOPASTY KONTAKT IPA+ 60ML. Spirit and other ethyl alcohols won’t be of great help, as they contain salicylate salts that leave white build-up after drying. It’s also a good idea to use dedicated agents for cleaning contacts, e.g. KONTAKT agents.

You need to remember not to use agents or preparations containing water to clean terminals or contacts. Therefore, despite being recommended by some, hydrogen peroxide solutions should be avoided.

After cleaning battery terminals, you need to make sure that their surface does not patinate or corrode again. To do that, you can use a greasy agent that will protect the surface of the contacts from oxidation without decreasing electrical conductivity.

To achieve that, you can use technical petroleum jelly in aerosol or copper lubricant – e.g. COPPER GREASE FROM AG TERMOPASTY. Caution: terminals should be protected after fastening them to battery posts, and then carefully sprayed on the outside. After evaporation, the petroleum jelly will form a shell that will effectively seal the connection without decreasing its electrical conductivity.

How to clean battery contacts?

Battery contacts are cleaned in a similar way to cleaning vehicle battery terminals. Usually, this is done after the so-called battery leak, and the process depends on the type of cells. If the electrolyte is spilt only on the surface of the battery and contacts, it can be removed easily and quickly.

It is considerably more difficult to remove electrolyte that got into an electric or electronic device and is corroding paths and integrated circuits. In such a case, it is necessary to disassemble the enclosure of the device and carefully inspect the condition of its components.

A good way to clean battery contacts from a spilt electrolyte is to use an ultrasonic bath. However, you can also use a cotton cloth or a cotton pledget soaked with vinegar that will remove electrolyte salts.

Next, contacts can be cleaned with water and spirit, but it’s better and safer to use isopropyl alcohol or a dedicated battery contact cleaner. Not only do such cleaners remove the electrolyte and patina, but they also absorb dampness from the system and protect the surface of the contact against corrosion and patination while keeping its resistivity unchanged.

Symbol: Description:
SMAR-CU-100 High-temperature lubricant; spray; Ingredients: copper; can
PG-49682 Brush; steel
IPA-60ML Isopropyl alcohol; 60ml; spray; can; colourless


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