| Word | Description |
| 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. |
| AC | Alternating Current - An electric current that varies periodically in magnitude and direction. A battery does not deliver alternating current. This periodic variation is counted in hertz. |
| Active Material | The chemical paste that adheres to the positive (+) and negative (-) electrodes in a battery and reacts with the sulfuric acid. |
| AGM | Absorbent Glass Mat - 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. |
| AH | Amp-Hour : 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. |
| 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 | (ANSI) - 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. |
| 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. |
| Amperage | The amount of current flow within a circuit, expressed in amps. |
| Ampere | (Amp) - The unit of measure for the amount of current that is flowing through a circuit. |
| Anode | The positive (+) terminal of an electrolyte battery. The negative (-) terminal of a primary cell battery. |
| ANSI | 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. |
| Application | The equipment in which a battery is used. |
| Automotive Battery | A battery designed to start an automobile, also known as a Starting, Lighting, and Ignition (SLI) battery. |
| 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. |