What causes a battery to corrode?

Corrosion of the car battery’s terminals happens during the charging process.

In the battery’s acid fumes and the condensate that forms can react with the battery terminals to create the white powdery substance on the battery terminals.

Corrosion may result from:

  • overcharging of the battery
  • crack in the battery case that leaks acid.

Effects of corrosion on car batteries

When the battery terminals are corroded, you may experience any of the following:

  • The car may fail to start, either because the powdery substance that forms is a poor conductor of current or part of the battery terminal has been eaten away.

    Either of these conditions results in a high resistance between the battery terminal(s) and connecting wire(s) which starves the engine starter from the current needed to start.
  • The car battery fail to charge fully because of the high resistance between the battery terminal(s) and connecting wire(s) which restricts current flow from the alternator to the battery.
  • A damaged battery. Severe corrosion eats away at the battery terminals affecting its ability to safely store energy in effect killing the battery. When this happens, the battery needs to be replaced.
  • Damaged wires connecting to the battery

How do you clean corrosion off car battery terminals?

First, disconnect the connecting wires from the battery terminals. For more information on which battery terminal to remove first,

[bg_collapse view=”button-orange” color=”#4a4949″ icon=”eye” expand_text=”Show More” collapse_text=”Show Less” ]To reduce the risk of an accidental short-circuit, the negative battery terminal should be disconnected first. This way, in the event of the positive wire touching the car’s body which serves as the negative wire, there is a minimal spark. This contrasts with the larger sparking and possible damage to the battery that can result if the positive wire is disconnected first and the wire accidentally touches the car’s body.[/bg_collapse]

To clean corrosion off battery terminals, mix baking soda with warm water or any other good quality battery cleaning solution then pour over the battery terminals.

Using a wire brush, old toothbrush, or scouring pad scrape off the powdery residue until the battery terminals are free of the powdery substance.

Make sure to clean the powdery residue off the connecting wires by pouring baking soda mixture over the terminals and brushing it off.

Finally, apply dielectric grease or vaseline on the clean battery terminals to protect the metal from fumes. before reconnecting the wires back to the battery terminals.

For more information on which battery terminal to connect first,

[bg_collapse view=”button-orange” color=”#4a4949″ icon=”eye” expand_text=”Show More” collapse_text=”Show Less” ]When connecting the battery wires to the battery, always start with the positive wire followed by the negative wire.[/bg_collapse]

To keep car battery terminals from corroding, periodically inspect the battery terminals for any corrosion and repeat the cleaning process above if you see any signs of corrosion.

Related Questions

Is it OK to put Vaseline on battery terminals?

Some people have reported using vaseline to prevent the build-up of corrosion successfully. I would recommend a professional auto care battery terminal corrosion inhibitor or terminal grease.

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