Battery Charging Requirements

Poor charging practice is responsible for shortening the life of a battery more than any other cause. Charging may be accomplished by various methods, but the objective of driving current through the battery in the opposite direction of discharge remains the same. The most important aspect of charging is matching the charger to the battery application. When choosing a charger, it is necessary to consider the type of battery, the way in which the battery will be discharged, the time available for charge, the temperature extremes the battery will experience, and the number of cells in the battery (output voltage). It is important to consult the battery manufacturer at the time of purchase to determine the appropriate charging method.

In general, lead-acid batteries may be recharged at any rate that does not produce excessive gassing, overcharge, or high temperatures. Discharged batteries may be recharged at a high current initially. However, once the battery approaches its full charge the current must be decreased to reduce gassing and excessive overcharging.

A wide variety of schemes exist for charging lead-acid batteries. Although a complete discussion of various charging techniques is beyond the scope of this Primer, a general description of the more common methods follows.