Battery Glossary | Batteriesnorthwest.com

Acid: Sulfuric acid, used to describe the electrolyte or liquid in a cell.

AGM: (Absorbent Glass Mat) A lead-acid battery that incorporates a sponge glass mat separator to immobilize the electrolyte. Because of the immobilized electrolyte, AGM batteries will not leak or spill.

Alloy: A combination of two or more metals. See Antimonial Lead Alloy and Calcium Lead Alloy.

Alternating Current: A pulsating electric current in which direction of flow is rapidly changed, so the terminal becomes in rapid succession positive, then negative. Abbreviated AC.

Alternator: Alternating current generators (alternators) produce alternating current that must be "rectified" (converted into direct current) before it can be used in an automobile.

Ambient Temperature: The surrounding temperature, usually refers to room temperature.

Ammeter: An instrument for measuring electrical current.

Ampere-Hour: A measure of the volume of electricity, being one ampere for one hour. It is used to express battery capacity, and is registered by an ampere-hour meter it can be obtained by multiplying the current in amperes by length of time that the current is maintained.

Ampere-Hour Meter: An instrument that registers the quantity of electricity in ampere-hours.

Anode: An electrode through which current enters any non-metallic conductor. Specifically, an electrolytic anode is an electrode at which negative ions are discharged, positive ions are formed, or at which other oxidizing reactions occur.

Antimonial Lead Alloy: The most commonly used alloy in battery castings. The percentage of antimony varies from 1/2% to 12%. Other substances are present in small quantities, either as inescapable impurities or by design to improve the properties of the cast part.

Atom: The smallest part into which an element can be divided and still retain the behavior of the element. Atoms consist of a positively charged nucleus and negatively charged electrons that constantly orbit the nucleus.

BCI: (Battery Council International) An association of battery industry companies whose members establish policy and standards for the industry.

BCI Group Number: The BCI Group Number defines a battery by describing the following characteristics:

Cadmium: A metallic element highly resistant to corrosion, used as a protective plating on certain parts and fittings.

Calcium Lead Alloy: A lead base alloy that is sometimes used for battery parts in place of antimonial lead alloys.

Capacity: The ability of a fully charged battery to deliver a specified quantity of electricity (Amp-Hr, AH) at a given rate (Amp, A) over a definite period of time (Hr) is defined by its capacity. The capacity of a battery depends upon a number of factors such as: active material weight, density, adhesion to grid, number, design and dimensions of plates, plate spacing, design of separators, specific gravity and quantity of available electrolyte, grid alloys, final limiting voltage, discharge rate, temperature, internal and external resistance, age and life history of the battery.

Capacity Test: A test that discharges the battery at constant current at room temperature to a cutoff voltage of usually 1.70 volts/cell.

Cathode: An electrode through which current leaves any non-metallic conductor. Specifically, an electrolytic cathode is an electrode at which positive ions are discharged, or negative ions are formed, or at which other reducing actions occur.

Cell (Primary): A cell designed to produce electric current through an electrochemical reaction that is not efficiently reversible and hence the cell, when discharged, cannot be efficiently recharged by an electric current.

Cell (Storage): An electrolytic cell for generation of electric energy, in which the cell after discharge may be restored to a charged condition by an electric current flowing in a direction opposite to the flow of current when the cell discharges.

Charged: A storage cell at maximum ability to deliver current. The positive plates contain a maximum of lead oxide and minimum of lead sulfate, and the negative plates contain a maximum of sponge lead and a minimum of sulfate, and the electrolyte is at maximum specific gravity.

Charged and Dry: A battery assembled with dry, charged plates and no electrolyte.

Charged and Wet: A fully-charged battery containing electrolyte and ready to deliver current.

Charging: The procedure to convert the chemicals in a storage battery to their original conditions by passing a higher voltage electrical current through the plates and electrolyte. Charging reverses the discharge of a battery and attempts to restore it to a useful state of charge.

Charging Rate: The current, expressed in amperes, at which a battery is charged.

Circuit: A system of electrical components through which an electric current is intended to flow. The continuous path of an electric current.

Cold Cranking Amp (CCA) Rating: The number of amperes a battery a 0^o Fahrenheit (-17.8^o) can deliver for 30 seconds and maintain at least a voltage of 1.2 volts per cell (7.2V for 12 V lead-acid batter).

Constant Current Charge: A charge that maintains the current at a constant value. For some types of batteries this may involve two rates, called a starting and a finishing rate.

Constant Voltage Battery Charger: A battery charger whose maximum voltage is limited and causes a decrease in charging current as the battery state of charge increases.

Continuity: The indication that a circuit is complete between two points. The opposite of an "open" circuit (infinite resistance).

Conventional Theory: A theory of current movement developed in the eighteenth century that assumed a current flows from the positive pole through the external circuit to the negative pole. The conventional theory has been accepted by the automotive industry and is still the prevalent theory taught to automotive technicians.

Corrosion: The chemical action of electrolyte on a metal that forms a new compound e.g., dilute sulfuric acid on steel forms the corrosion compound, rust. Battery terminals can be subject to corrosion.

Cranking Amps (CA): A test similar to Cold Cranking Amps but conducted at 32^o F. this test leads to higher ratings for the same battery and should not be confused with the original equipment manufacturer's specifications given in "Cold Cranking Amps". To convert CA at 32^oF to CCA, multiply CA by .8 or divide CA by 1.25.

Creepage: Travel of electrolyte up the surface of electrodes of other parts of the cell above the level of the main body of the electrolyte.

Current: The time rate of flow of electricity, normally expressed as amperes, like the flow of a stream of water.

Cycle (Battery): A battery discharge followed by a complete recharge.

Cycling: The repeated charge/discharge cycle of a storage battery. some batteries are rated as to their ability to withstand repeated, deep discharge cycles.

Deep Cycle Batteries: Batteries that are designed to withstand repetitive deep cycling and continue to provide their rated capacity even after hundreds of cycles. They are used primarily in Marine/RV applications.

Deep Discharge: Removal of up to 80% of the rated capacity of a cell or battery.

Direct Current: A one-direction current. Abbreviated DC.

Discharge: Conversion of a battery's chemical energy into electrical energy.

Discharge Rate: Batteries discharged to meet any time rate between 3 and 8 hours are considered as having been normally discharged.

Discharged: A storage cell when, as a result of delivering current, the plates are sulfated, the electrolyte is exhausted, and there is little or no potential difference between the terminals.

Dry Charged: A negative plate that has been subjected to the dry charging process.

Electricity: The flow of electrons through conductive materials and devices.

Electrolysis: The process of chemically breaking down the water in electrolyte. This breakdown causes hydrogen to be given off at the negative plates and oxygen at the positive plates.

Electrolyte: In a lead-acid battery, the electrolyte is sulfuric acid diluted with water. The approximate volume proportion of sulfuric acid to water in a fully charged liquid electrolyte battery is 25% sulfuric acid and 75% water (1.265 specific gravity). A lead-acid battery may have a liquid, gelled, or immobilized electrolyte. The electrolyte is a conductor and plays a key role in the chemical reaction that produces the electricity required for the battery to supply energy.

Electromotive Force (EMF): Most often called "voltage" (symbol E). It is the pressure applied to move electrons in a complete circuit. In a storage battery, EMF is the difference in potential between the positive and negative poles. Potential is limited by the number and type of cells and the strength of the electrolyte. EMF or voltage is measured by using a "voltmeter" connected in parallel tot he circuit being measured.

Electron: Negatively charged particles in orbit within an atom. Electrons in some atoms (conductors) can be made to move by applying electromotive force (voltage).

Electron Theory: This theory describes the movement of free electrons from the negative pole through an external circuit to the positive pole. It is the opposite of an earlier "conventional theory". The direction of electron movement is important when technicians study "electronics".

Equalizing Charge: An extended charge given to a storage battery to ensure complete restoration of active materials in all the plates of the cells.

Float Charging: A recharge at a very low rate, accomplished by connection to a buss whose voltage is slightly higher than the open circuit voltage of the battery.

Flooded: Describes a type of lead-acid battery filled with liquid electrolyte and vented to the atmosphere.

Formation or Forming Charge: An initial charging process that electrochemically converts the raw paste of the plates into charged active material, lead peroxide in the positive plates and sponge lead in the negative plates.

Fuse: A component of a circuit placed in series and designed to melt "open" at a specific level of current. Fuses protect circuits from dead shorts and/or a rapid increase in circuit current.

Fusible Link: A type of fuse consisting of short strands of wire held together by solder. Color coded outer layers identify the level of current at which they will "open". Fusible links may be located anywhere in a circuit.

Gassing: Bubbles from gases being released at one or more of the electrodes during electrolysis.

Gel Cell Battery: A lead-acid battery in which the electrolyte is immobilized by adding a gelling agent. This battery has the advantage of being non-spillable. A gel cell battery is totally sealed, valve regulated, with no possible access to the cells.

Glass Mat: Fabric made from glass fibers with a polymeric binder such as styrene or acrylic which is used to help retain positive active material.

Grid: A metallic framework used in a battery for conducting electric current and supporting the active material.

H₂SO₄: Sulfuric Acid

Hydrometer: A device used to measure density or specific gravity of electrolyte solutions.

Immobilized Electrolyte: An electrolyte made motionless by use of a gel additive or AGM separator.

Impedance: The term that describes resistance in an AC circuit.

Internal Resistance: Resistance within a cell or battery to the flow of electric current, measured by the ratio of the change in voltage to a specified change in current for a short period of time.

Kilovolt: One thousand volts.

Kilowatt: One thousand watts.

Kilowatt Hours: A measure of energy or work accomplished, being 1000 watt hours.

Lead Oxide: A general term for any of the lead oxides used to produce batteries.

Lead Sponge: The chief component of the active material of a fully-charged negative plate.

Lead Sulfate: A compound that results from the chemical action of sulfuric acid on oxides of lead or on lead metal.

Lead-Acid Battery: A storage battery using lead (Pb) and lead peroxide (PbO₂) as the "active" materials and an electrolyte solution of water and sulfuric acid (H₂SO₄). A storage battery is a series of secondary cells that can be repeatedly discharged and recharged. Maintenance Free, Low Maintenance and Gel Cells are types of lead-acid batteries.

Load: The "built in" resistance in a circuit. The load is the motor, lamp or resistor in a circuit. Loads are carefully designed to control the circuit current.

Load Tester: An instrument that draws current from (discharges) a battery using an electrical load while measuring voltage. A load tester determines the battery's ability to perform under actual operating conditions.

Low-Maintenance Battery: A battery that does not require periodic water addition under normal service conditions. it typically uses a low antimony lead alloy in the positive grid and a calcium lead alloy in the negative grid. It can be referred to as a dual alloy battery.

Maintenance-Free Battery: A battery that requires no added water or boost charges. Typically composed of a grid design that minimizes antimony and includes seals-cell design or low-loss venting.

Marine Cranking Amps (MCA): An industry recognized test to rate the current output of marine batteries at 32^o Fahrenheit. This rating is only acceptable in ads if the CCA rating appears in equal prominence.

Millivolt: One thousandth of a volt.

Motive Power Battery: A cycle service battery designed to provide energy necessary to electrically-powered industrial trucks.

Negative Plate: The grid and active material that current flows to from the external circuit, when a battery is discharging.

Negative Terminal: The terminal that current flows toward in the external circuit from the positive terminal.

OHM: A unit of electrical resistance.

OHM's Law: An equation that expresses the relationship between voltage, current and resistance in an electrical circuit. The equation can be expressed as follows: Volts (E) = Amps (I) X Ohms (R)
If any two of the three values are known, the third value can be calculated.

Ohmmeter: An instrument used to measure resistance in an electrical circuit.

Open Circuit: The state of a battery when not connected to either a charging source or a load circuit.

Open Circuit Voltage: The voltage at a battery terminal when no appreciable current is flowing.

Parallel Circuit: A circuit in which the current has more than one path to follow.

Pb: Chemical symbol for lead.

PbO₂: Chemical symbol for lead peroxide.

Photovoltaic: Material that generates voltage when exposed to light. Used to produce solar cells.

Plate: A pasted grid.

Polarity: The quality of an object characterized by two opposite charges, as in the positive and negative poles of a battery.

Polarization: Change in voltage at terminals when a specified current is flowing equal to the difference between the actual and the equilibrium (constant open circuit condition) potentials of the plates, exclusive of the internal resistance drop.

Porosity: The ratio of open spaces or voids in a material to the volume of its mass.

Positive Plates: The grid and active materials of a storage battery from which current flows tot he external circuit tot he negative terminal when the cell discharges.

Post: Terminal or other conductor that connects the plated group strap to the outside of the cell.

Primary Battery: A non rechargeable battery. A storage battery is a secondary battery that is rechargeable.

Random-Access Memory (RAM): That part of a microprocessor or computer into which information can be written and from which information can be read. The term also designates read/write memory.

Read-Only Memory (ROM): Pre-programmed, permanent memory used by the computer's processor.

Rectifier: A device that converts alternating (ac) current into unidirectional (dc) current because of a characteristic that permits appreciable flow of current in only one direction.

Reserve Capacity Rating: The time in minutes that the battery at 80^o Fahrenheit will deliver 25 amps until it falls below 1.75 volts per cell (10.50volts for 12 v battery).

Resistance: The opposition of a conductor tot he passage of an electrical current, usually expressed in ohms.

Resistor: A device used to introduce resistance into an electrical circuit.

Scrap: Pre-cast or cast-on piece of lead or lead alloy used to connect plates into groups and to connect groups to the post.

Secondary Battery: A battery that can store and deliver electrical energy and can be recharged by passing direct current through it in a direction opposite to that of discharge.

Sediment Space: The portion of a container beneath the element sediment from the wearing of the plates collects here without short-circuiting.

Self Discharge: Loss of charge due to local action.

Semiconductors: Materials that are neither good conductors nor insulators.

Series Circuit: A circuit in which the current has only one path to follow.

Series Parallel Circuit: A circuit containing elements of both a series circuit and a parallel circuit.

Short Circuit Current: The current that flows when the two terminals of a cell or battery are inadvertently connected to each other.

Side Terminal: SLI battery design with two through-the-container current connections on one side instead of two posts on top.

Sine Wave: A representation of an alternating current cycle.

SLI Battery: A battery for automotive use in starting, lighting and ignition.

Smelting: The primary process for recovering lead and antimony from scrapped batteries and scrap from battery manufacture.

Solenoid: (1) A term used to mean coil or inductor.

Specific Gravity (Sp. Gr.): The specific gravity of battery electrolyte is the weight of the electrolyte compared to the weight of an equal volume of pure water.

Sponge Lead: (Pb) A porous mass of lead crystals and the chief material of a full-charged negative plate.

State of Charge: The amount of electrochemical energy left in a cell or battery.

Sulfated: A plate or cell whose active materials contain an appreciable amount of lead sulfate.

Sulfation: Formation of lead sulfate on a plate or cell as a result of discharge, self-discharge or pickling.

Sulfuric Acid: (H₂SO₄) The principal acid compound of sulfur, sulfuric acid in dilute and highly pure form is the electrolyte of lead-acid storage cells.

Treeing: Growth of a lead dendrite or filament through a crack or hole of a separator, short-circuiting the cell.

Trickle Charge: A low-rate continuous charge approximately equal to a battery's internal losses and capable of maintaining the battery in a fully-charged state.

Vent: An opening that permits the escape of gas from a cell or mold.

Vent Plug: The seal for the vent and filling well of a cell cover, containing a small hole for escape of gas.

Vented Cell: A cell in which the gaseous products of electrolysis and evaporation are allowed to escape into the atmosphere as they are generated. These cells are commonly referred to as "flooded" cells.

Volt: The unit of measurement of electromotive force, being the force needed to send a current or one ampere through a conductor with a resistance of one ohm.

Voltage Drop: The net difference in the electrical potential (volts) when measured across a resistance or impedance (ohms). Its relationship with current is described in Ohm's Law.

Voltage Regulator: A device designed to limit the charging voltage in a vehicle or to provide a specific voltage in a discrete circuit. Most electronic regulators use "zener" diodes for regulation.

Voltage Spike: A high voltage surge created by the collapse of an electromagnetic field in a relay or coil.

Voltmeter: The meter or instrument used to measure the amount of voltage in a circuit.

Watt: The unit of measurement for electrical power. The algebraic symbol of a watt is "W".

Watt-Hour (Watt-Hr, Wh): The unit for measuring electrical energy that equals Watts X Hours.