Show CartA common cause of car battery failure is acid stratification. Acid stratification occurs in your car battery when the electrolytes concentrate at the bottom of the battery, causing the upper half of the battery to be acid poor. This effect is similar to a cup of coffee in which the sugar collects on the bottom of the mug when you forget to stir.
You do not want acid concentration light on top and heavy on the bottom of a car battery. Light acid limits plate activation, promotes corrosion and reduces overall battery performance. Plus, high acid concentration on the bottom artificially raises the open circuit voltage. When this happens, the battery appears fully charged but provides a low CCA. High acid concentration in a battery also promotes sulfation and decreases the already low conductivity further. If unchecked, such a condition will eventually lead to battery failure.
If the acid in your car battery should stratify, allow the battery to rest for a few days, then apply a shaking motion and/or tip the battery unit over.