Lead-Acid Storage Batteries
Proper maintenance will prolong the life of a battery and will aid in assuring that it is capable of
satisfying its design requirements. A good battery maintenance program will serve as a
valuable aid in determining the need for battery replacement. Battery maintenance should
always be performed by trained personnel knowledgeable of batteries and the safety
Most of the following material concerns flooded, non-maintenance-free batteries. However, so
called "maintenance-free" and valve-regulated batteries also require some maintenance. They
do not require water addition or checking of specific gravity, but they may require periodic
cleaning, monitoring of cell and battery total float voltage, load (capacity) testing, terminal
resistance measurement, or cleaning and torquing of terminal bolts depending on the
importance of the application.
In general, a good maintenance and inspection program should be based on the
recommendations in ANSI/IEEE Std 450, IEEE Recommended Practice for Maintenance,
Testing, and Replacement of Large Lead Storage Batteries for Generating Stations and
Substations; and in DOE-STD-3003-94, Backup Power Sources for DOE Facilities. Some of
the recommended practices from these and other references are presented in the following
Flooded lead-acid batteries can function for 10 years or longer if properly maintained. The six
general rules of proper maintenance are
Match the charger to the battery requirements.
Avoid overdischarging the battery.
Maintain the electrolyte at the appropriate level (add water as required).
Keep the battery clean.
Avoid overheating the battery.
Provide an equalizing charge periodically to weak batteries/cells.
Matching the Charger to Battery 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