What Is Car Battery Acid Stratification And How Does It Cause Premature Battery Failure?

car battery acid stratificationCar battery acid stratification is a possibility all motorists should be aware of, which is a phenomenon that can cause cells to fail in lead-acid batteries. But what is acid stratification? We will go through the basics of it to hopefully help you be better equipped to prevent it.

While there have been regular advancements in vehicle batteries’ performance, their general components have been the same since the 1880s. A standard lead-acid battery contains a liquid mix of sulfuric acid and water. This mixture is called the electrolyte.

Stratification occurs when the electrolyte solution in a lead-acid battery becomes uneven, with a higher concentration of sulfuric acid at the bottom and a lower concentration at the top.

This can happen when a battery is not used frequently or is charged improperly, leading to reduced battery performance and a shorter lifespan. To prevent stratification, it’s recommended to regularly use the battery and maintain proper charging techniques.

The electrolyte should be evenly distributed between the top and bottom of a battery. An even concentration within the liquid is vital for the optimum performance of cells. If the acid concentration settles on the bottom of the battery, this is called car battery acid stratification. It causes sulfation in the plates located in the bottom half, significantly reducing a battery’s lifespan due to accelerated corrosion.

car battery acid stratification

Which drivers are more prone to experience this battery condition?

Anyone that does short-distance driving every day, has irregular car usage or has a faulty under-charging alternator. It is a common problem with city dwellers who live in proximity to their amenities. The result is, that the alternator is not allowed to give sufficient daily charge to the battery.

Owners of classic or sports cars, and industrial or farm equipment that sits idle for long periods of time also suffer from stratification.

How Do You Prevent Car Battery Acid Stratification From Forming?

Equalization charge

Stratification can occur if a battery is undercharged. You must make sure that the charger voltage is high enough to charge the battery properly and spread the electrolyte solution evenly. To prevent stratification, you can perform an equalization charge with a CTEK charger, which balances the electrolyte’s voltage and specific gravity in your vehicle’s battery. Specific gravity refers to the ratio of the liquid solution’s weight to the water’s weight at a specific temperature. Equalization also prevents the build-up of sulfate crystals.

Which Fully Automated CTEK Charger Do We Recommend?

For the enthusiast looking for the following features with a 5 Year Warranty:

  1. Diagnose the battery’s condition to determine if it can take charge due to deep discharging and sulfation.
  2. Suitable for lead-acid, AGM and Stop-Start batteries.
  3. Patented Float-Pulse maintenance to keep batteries at an optimum charge, therefore increasing longevity.
  4. A fully automated process protects the electronics of the vehicle, spark-free and reverse-polarity protected and proofed from short-circuiting.
  5. Ready to check out even more features at an affordable price?


ctek car battery charger

ctek mxs 5.0 charger


If you are a driver who makes short trips frequently or doesn’t use your car often enough, get your battery checked regularly. Keep your battery at optimum charge at all times to get its maximum starting and auxiliary life cycles.

We highly recommend a great resource on common frequently asked battery questions. (Opens in new window)

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