Battery Failure Mode: Undercharging
If either the negative or positive plate is continually undercharged, a premature decline in capacity will occur because of Sulfation. Undercharging is on the rise across the world in vehicles of every type. Undercharging can be caused by defective charging or persistent Partial State of Charge (PSOC) operation. Defective charging can happen as a result of faulty equipment or as a result of some of the other battery failure modes discussed in this document. PSOC operation is a growing trend due to the growing number of vehicle systems that rely on the battery to properly function and the deep and micro-cycling that occurs in start-stop vehicles.
In addition, battery failure due to undercharging is accelerated by the effects of acid stratification. For this reason and the others discussed in this document, it is not surprising that average battery life is declining for the first time since the beginning of the 20th century.