Environmental Factors

• Certain environmental factors can be a cause of battery terminal corrosion. These can include a saltwater or salty air environment, such as exists near the ocean or other areas. This factor can initiate or accelerate the corrosion of the battery terminals. Pollutants in the air can also be a factor in areas where acid rain and other issues are commonly found.
  
  

Leaking or Venting Battery Gas

• By far the most common cause of battery terminal corrosion is a leaking battery or the venting of the sulfuric acid inside of the battery itself. This acid turns to vapor and can then escape through cracks or other leaks in the battery casing. When it contacts the battery terminals and battery cables, it can cause a white or bluish-white build-up of lead sulfate salts. Over time, this can lead to poor starting, undercharging or failure of the battery or cables entirely.
  
  

Low Battery Water

• Low battery water in the cells of batteries that are not sealed can cause battery corrosion. The acid inside of the battery is more likely to turn into a vapor if it is not mixed with water, so a low water condition can accelerate the leaking or venting of battery acid gases.
  
  

Rust From Cable Fastening Devices

• Rust from battery cable fastening devices and battery tie down straps can also cause battery terminal corrosion. If you notice a reddish-brown rust on the terminals and cable ends of your battery, it is likely rust that is chemically forming on the steel cable bolts or on the tie down, and is reacting with the electromagnetic charges of the battery to affix itself to the lead battery terminals.