What to put on battery terminals to stop corrosion

To stop corrosion and oxidation, put NANOPROTECH Dielectric on battery terminals: it displaces moisture, restores contact conductivity and leaves a non-drying, water-repellent film that protects for up to 1 year. Before treatment, remove the oxidation with Electrical contact cleaner. For machinery that works in damp and aggressive environments, there is the industrial coating Electric.

What you need

Dielectric innovative protection

Innovative protection for electrical equipment

Sizes: 210 ml, 400 ml, 650 ml

Industrial electric

Dielectric coating for electrics

Sizes: 210 ml, Bulk

Cleaner for electrical contacts, 210 ml

For electronics and contacts

Why battery terminals oxidise

Terminals oxidise under the action of moisture, condensation, road de-icing chemicals and electrolyte. A layer of oxides forms on them, often a furry crust. It worsens the contact: the voltage drops, the battery charges less well and the engine may be hard to start. A protective film keeps out moisture and oxidation, so terminals are treated after every cleaning.

How to treat battery terminals — step by step

1. De-energise the circuit and remove the terminals. Stop the engine, switch off the ignition and all consumers, and let hot parts cool. Battery terminals stay live even with the ignition off, so remove them: negative first, then positive.
2. Clean the terminals and posts. Brush off thick deposits first. Then shake the can of Electrical contact cleaner and spray the terminals and battery posts.
3. Let the cleaner evaporate. It evaporates completely, so there is nothing to rinse off. If oxidation remains, repeat the treatment.
4. Apply Dielectric. Shake the can and spray a thin layer from 20–30 cm onto the terminals and posts, including their mating surfaces: when the terminals are tightened, the film is squeezed out of the contact point.
5. Wait 10 minutes. Wipe off any excess that could collect dust with a cotton cloth — the protective layer remains.
6. Reconnect the battery. Fit the terminals — positive first, then negative — and tighten them firmly. Wipe off any drips after assembly.

What should you put on battery terminals if the vehicle works in damp, frost or road chemicals? Instead of Dielectric, you can apply Electric: it contains more antioxidants and anti-corrosion additives. It is applied in the same way, to removed and cleaned terminals, at −20 °C to +35 °C and from 20–30 cm, and left for 15 minutes to start working. The operating temperature of the coating is −80 °C to +250 °C.

To clean oxidation off other contacts — connectors, sensors, circuit boards — see how to clean oxidised contacts.

Why it may not work

• Protection was applied over oxidation. Protective sprays go on a clean surface. Remove the deposits with a brush and the cleaner first and wait until it has evaporated; if deposits remain, repeat the treatment.
• The terminals were not tightened enough. The protective film is no substitute for a tight contact. After treatment, tighten the terminals securely on the battery posts.
• The excess was not wiped off. On exposed surfaces the non-drying film collects dust. Wipe off the excess with a cotton cloth after the 10-minute wait.

Safety precautions

• Treat terminals removed from the battery, with the ignition off. The products are flammable: do not spray them near live equipment, open flames or hot parts.
• Do not spray the products near a battery while it is charging or just after: during charging it gives off flammable gas.
• The cans are pressurised: do not heat them above +50 °C or leave them in the sun, and do not puncture or burn them, even when empty.
• Work in a well-ventilated area.
• In case of eye contact, rinse with water; on skin, wash with soapy water. Keep the cans out of the reach of children.

Frequently asked questions