Battery Terms: A

ANSI - American National Standards Institute.

Absorbent Glass Mat (AGM) - A separator technology used in some sealed lead-acid batteries in which the glass-mat separator absorbs 100% of the electrolyte. Because of the immobilized electrolyte, an AGM battery will not leak or spill and does not require water addition. This battery is used in deep-cycle and specialty applications such as telecommunications, wheelchairs and security alarm systems, as well as in automotive starting applications.

Active Material - The chemical paste that adheres to the positive (+) and negative (-) electrodes in a battery and reacts with the sulfuric acid.

Alkaline Battery - A nonrechargeable, dry-cell battery — such as a AA, AAA, C, D or 9-volt battery — that uses alkaline aqueous solution for its electrolyte. It has a greater capacity than some other types of dry-cell batteries.

Alloy - A mixture of different types of metals or a mixture of a metal and a nonmetal.

Alternating Current (AC) - An electric current that varies periodically in magnitude and direction. A battery does not deliver alternating current. This periodic variation is counted in hertz.

Alternator - An alternating-current generator that produces and rectifies current so that it can be used in an automobile.

American National Standards Institute - An organization, sponsored by the National Electric Manufacturers Association (NEMA), that establishes policy and standards regarding cell sizes, terminals and testing procedures.

Ammeter - An instrument that measures the flow of current in amps. Ammeters can be made to read DC (Direct Current) and AC (Alternating Current.)

Amp - Short for ampere, it is the unit of measure for the amount of current that is flowing through a circuit.

Amperage - The amount of current flow within a circuit, expressed in amps.

Ampere - amp.

Amp-Hour (AH) - The unit of measure for a battery's electrical storage capacity, obtained by multiplying the current in amps by the time in hours of discharge. Example: A battery delivering 10 amps for 20 hours = 10 amps x 20 hours = 200 AH.

Anode - (1) The positive (+) terminal of an electrolyte battery. (2) The negative (-) terminal of a primary cell battery.

Application - The vehicle or equipment in which a battery is used.

Automotive Battery - An SLI battery. (illustration)

Average Drain - The average current withdrawn — i.e., the drain — from a cell or battery during discharge, usually approximated by calculating the current at 50% depth of discharge.