Acid Corrosion – Causes and Cures.

Have you ever lifted your hood and found corrosion on your battery terminals? Yuck! Not only is it unsightly, but corrosion build up can also build up between your terminals and wires – causing hard starts and dead batteries. (fig.1)

What causes this build up? 

As you know from our Anatomy of a Battery article, automotive batteries are filled with sulfuric acid. (fig.2) As your battery heats and cools with your motor, hydrogen gasses are released from the battery through the vents in the battery. (fig.3) These gasses mix with other particulates around the battery. That mixing produces corrosion which forms on electrical connections – which is why we find it on our battery terminals.

How can we get rid of corrosion?

There’s no easy way to get rid of the corrosion – it just needs a good cleaning. To get those terminals clean, there are a couple of avenues you can follow. Ideally, you’ll have a wire brush (fig.4) handy and some battery cleaner. (fig.5) If these aren’t available to you, some baking soda mixed with a little water will take the place of battery cleaner, and a toothbrush works in place of a wire brush. Just be prepared to scrub a little harder!

How can we prevent corrosion?

There are multiple ways to prevent corrosion from building up on your battery terminals. These solutions should always be applied to freshly cleaned or new batteries!

  • Use a spray battery protector. This applies a protective layer to the terminals and connectors. (fig.6)
  • Apply an anti-corrosion gel to your terminals before connecting the battery cables. This may not protect the rest of the connector, but corrosion won’t build on the terminal. So no more worries about hard starts. (fig.7)
  • Use felt terminal protectors. These are impregnated with a corrosion inhibitor. They’re fairly popular because they prevent corrosion without the mess of sprays or gels. (fig.8)

Next time you get stuck replacing the battery in your car or truck, consider implementing these preventative measures to stop corrosion before it becomes a problem.

Thanks to Becky C. for the question!