Battery Glossary

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.

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.

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.

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.

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

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.

Battery

A device that produces and stores electrical energy as a result of a chemical reaction. A 12-volt battery has six individual 2-volt cells that contain positive (+) plates and negative (-) plates that create electrical current. A fully charged 12-volt battery produces at least 12.66 volts.

Battery Charge

See State of Charge.

Battery Council International (BCI)

An association of battery industry companies whose members establish policy and standards for the industry.

Battery Group Size

See Group Size.

BCI

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

BCI Group Number

See Group Size

Boost Charging

Charging at an extremely high rate of 50-300 amps, this method is primarily used to rapidly charge a battery in order to start a vehicle in a matter of a few seconds to five minutes.

Button Cell

A single-cell, miniature battery, such as a watch battery, that is the size and shape of a button.

cranking amps

Capacitor

A device that can store a charge on conducting plates, it is most frequently called a condenser, as in "points and condenser," in an automobile.

Capacity

The ability of a fully charged battery to deliver a specified quantity of electricity (AH) at a given rate (amps) over a definite period of time (hours).

Carbon-Zinc Battery

A general-purpose battery, made of a carbon-zinc alloy, such as a AA, AAA, C, D or 9-volt battery. It typically has a lower capacity than alkaline batteries but is used in the same applications, e.g., flashlights.

Cathode

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

CCA

cold-cranking amps

CCV

closed-circuit voltage

Cell (Dry)

The basic unit that converts chemical energy directly into electric energy. Typically consists of two electrodes of dissimilar material isolated from one another electronically in immobilized electrolyte. See also Dry-Cell Battery.

Cell (Flooded)

The basic unit that converts chemical energy directly into electric energy. Typically consists of a set of positive (+) plates, negative (-) plates, liquid electrolyte, separators and casing. A 12-volt battery has six cells.

Cell Mismatch

The condition of a battery pack that contains cells with significant variations in voltage or capacity. In a liquid-electrolyte battery, cell mismatch may be determined using a hydrometer.

Cell Reversal

See Reversed Polarity

CEMF

counter electromotive force

Charging

The process of supplying electrical energy to a discharged battery for conversion to stored chemical energy.

Charging Voltage

The voltage used to overcome a battery's internal resistance and to recharge the battery.

Circuit

The path followed by a current. See also Open Circuit, Parallel Circuit and Series Circuit.

Closed-Circuit Voltage (CCV)

The voltage of a battery when the cell or battery is under a specific discharge load and time interval. See also Open-Circuit Voltage.

Coin Cell

A miniature battery - typically a single-cell - such as a keyless-remote or camera battery, that is the size and shape of a coin.

Cold-Cranking Amps (CCA)

A rating that is used to define the battery's ability to start an engine under low-temperature conditions. BCI defines it as "the number of amps a lead-acid battery at 0ºF (-17.8ºC) can deliver for 30 seconds and maintain at least 1.2 volts per cell (7.2 volts for a 12-volt lead-acid battery)". See also CA and HCA.

Conditioning

(1) The process of restoring capacity to a nickel-cadmium or nickel-metal-hydride battery by deeply discharging and recharging the battery multiple times. (2) The process of preparing a lead-acid battery for a set of standard electrical tests by a precise charge regime.

Conductance

The ability of a circuit to conduct current. It is the mathematical reciprocal of electrical resistance.

Conductor

A material that allows the movement of electrons (current), such as the metals used for wire and contacts. The best conductors are gold, silver and copper, followed by lead, aluminum and steel.

Constant Current

Charging or discharging method in which current does not change appreciably in magnitude regardless of battery voltage or temperature.

Constant Resistance

A situation during discharge in which the resistance of the application remains constant.

Constant-Current Battery Charger

A battery charger with output current that stays relatively constant as the battery state of charge increases.

Constant-Current Discharge

A discharge in which the current drawn from the battery remains constant.

Constant-Voltage Battery Charger

A voltage-regulated battery charger that allows a decrease in charging current as the battery state of charge increases.

Continuity

The indication that a circuit is complete between two points; continuity does not exist in an open circuit.

Continuous Test

A battery test in which the battery is continuously discharged until it reaches a predetermined voltage.

Corrosion

A destructive chemical reaction with a reactive metal that forms a new compound. Saltwater or dilute sulfuric acid on steel, for example, forms the corrosion compound, rust. Battery terminals can be subject to corrosion.

Counter Electromotive Force (CEMF)

The voltage that is produced within the battery, mainly by chemical means, that opposes the charging voltage.

Cranking Amps (CA)

A rating that is used to define the battery's ability to start an engine in moderate temperature conditions. BCI defines it as "the discharge load in amps that a new, fully-charged battery at 32ºF (0ºC) can continuously deliver for 30 seconds while maintaining a terminal voltage equal to or higher than 1.20 volts per cell." This artificially high rating should not be confused with CCA, which is conducted at 0ºF (-17.8ºC).

Cranking Battery

An SLI battery

Current (I)

The rate that electricity flows through a conductor, such as the wire in a battery cable. Current is measured in amps. See also Alternating Current and Direct Current.

Current Drain

The current withdrawn from a battery during discharge. See Drain

Cutoff Voltage

The voltage at the end of useful discharge. When battery voltage is below this level, the connected equipment will not operate and operation is not recommended.

Cycle

One sequence of battery activity, which is a battery discharge followed by a complete recharge.

Cycle Life

The total number of cycles a battery can undergo before it no longer performs at a predetermined minimum rated capacity.

Cycling

The repeated charge/discharge cycle of a battery. Some batteries are rated according to their ability to cycle.

Cylindrical Battery

(1) A battery that has a height greater than its diameter. (2) A battery made up of cylindrical cells.

Cylindrical Cell

A battery cell design in which the positive (+) plates and negative (-) plates are rolled up and placed into a cylindrical-shaped container. In Interstate's Extreme Performance batteries, this construction is called Spiralcell® technology.

direct current

Deep Discharge

The discharge of the battery to below the specified cutoff voltage before the battery is replaced or recharged.

Deep-Cycle Battery

A battery that is designed to withstand repetitive discharges to a 20% depth of discharge or more and to continue providing its rated capacity after hundreds of cycles. Deep-cycle batteries are often used in marine/RV and industrial applications.

Depth of Discharge (DOD)

The percent of rated capacity to which a cell or battery is discharged. It is the reciprocal of a battery's state of charge. Example: a battery that has a depth of discharge of 45% has a state of charge of 55%.

Digital Voltmeter (DVM)

See voltmeter

Diode

A semiconductor device that acts like a one-way valve for current. Today's alternators use diodes to rectify current.

Direct Current (DC)

An electrical current that flows in one direction only. A battery delivers direct current, discharging the battery, and is recharged with direct current.

Discharge Rate

The rate at which current is drawn from a battery, usually expressed in amps.

Discharged

The state of a battery when it has less than a 100% state of charge. Levels of discharge are shown in the Open-Circuit-Voltage Chart.

Discharging

The withdrawal of electrical energy from a cell or battery, usually to operate connected equipment. A battery is discharging when it delivers current.

Distilled water

If the water level in your battery is low, Interstate Batteries recommends adding nothing but distilled water to a vehicle battery. No other additives have been proven to extend battery life and may actually decrease it.

Drain

Withdrawal of current from a cell or battery. Often referred to as discharging. See also Average Drain and Initial Drain.

Dry Battery

A battery in which the electrolyte is immobilized, being either in the form of a paste or absorbed into the separator material.

Dry-Cell Battery

A cylindrical-cell battery, typically nonrechargeable and disposable, such as a standard alkaline, heavy-duty or general-purpose battery. See also Cell.

Dual-Alloy Battery

See Low-Maintenance Battery.

Dual-Terminal Battery

An automotive battery with top terminals and side terminals.

Duty Cycle

The time duration and use frequency during which a battery is drained. It is affected by such factors as charge and discharge rates, depth of discharge, length of cycle, and length of time in standby mode.

volt

Electricity

The flow of electrons through conductive materials and devices.

Electrode

A conductor used to establish electrical contact with a nonmetallic part of a circuit

Electrolysis

The chemical process that breaks down the water in the electrolyte, releasing hydrogen from the cathode and oxygen from the anode.

Electrolyte

The dilute solution of approximately 25% sulfuric acid (H2SO4) and 75% water by volume in a lead-acid battery, it conducts electricity required for the battery to supply energy. A lead-acid battery may have a liquid, gelled or immobilized electrolyte.

Electromechanical

Of, relating to, or being a process or device that converts electrical energy into mechanical movement. A starter motor and an alternator are electromechanical devices.

Electromotive Force (EMF)

voltage

Electron

A negatively charged particle that orbits the nucleus of an atom.

Element

In a battery, a set of positive (+) plates and negative (-) plates along with separators.

EMF

electromotive force, which is another term for voltage

Energy Density

The ratio of a battery's energy-delivery capability to its weight or volume, measured in watt-hours per kilogram or watt-hours per cubic centimeter.

Equalizing Charge

A charging method that equalizes the specific gravity or voltage levels of individual cells in a battery or a group of batteries connected in series.

Fast Charge

A high rate charge — typically above 20 amps — for one to five hours that provides a quick blast of energy. It is often used to get the battery to a recharge level that can restart a vehicle. Repeated fast charges overcharge the battery and reduce service life.

Float Charge

A low, constant-current or constant-voltage charge that compensates for the self-discharge of a battery normally used in a standby application.

Flooded Battery

A type of liquid, lead-acid battery. See Vented Battery.

Frequency

The number of times that a periodic function, such as current or voltage, repeats the same sequence of values within a unit of time. It is measured in hertz.

Fuse

A safety device in a circuit that melts "open" at a specific level of current in order to protect the circuit from shorts circuits and current surges.

Fusible Link

A type of fuse in a circuit consisting of a reduced number of strands of wire held together by solder.

Gassing

The production of gas in a battery due to the chemical reaction during recharging

Gel-Cell Battery

A recombinant-chemistry, lead-acid battery in which the electrolyte is immobilized by adding a gelling agent. Totally sealed and valve-regulated, it is nonspillable and does not require water addition. Gel-cell batteries are used in special applications such as telecommunications, wheel chairs and security alarm systems.

General-Purpose Battery

The least expensive of the typical dry-cell batteries, it has the lowest capacity and is suitable only for low-drain applications, such as TV remote controls, clocks and keyless remotes.

Grid

A lead-alloy framework that supports the active material of a battery plate and conducts current. In SLI batteries, it may contain antimony or calcium to make it more rigid.

Ground

A large conducting body, such as the metal frame of a vehicle, used as a common return for an electric circuit and as an arbitrary zero of potential. When jump starting or installing a battery, it is important to identify the ground cable to avoid damage when attaching the cable to the ground. The negative (-) terminal of the battery is used as the ground in 99% of automotive applications today.

Ground Cable

The cable which connects the ground - e.g., the metal frame of the vehicle - to the battery, normally to the negative (-) terminal.

Group Size

The physical dimensions of a battery. BCI assigns letters and numbers for North American battery size types. All group-size-24 batteries, for example, have similar container dimensions, terminal orientation and terminal types.

Hazardous Waste

Waste that is classified by the government as potentially harmful to the environment. Lead and cadmium are examples of chemicals that are particularly hazardous.

HCA

hot-cranking amps

heavy duty

Heavy-Duty Battery (Commercial)

A lead-acid, liquid-electrolyte, starting battery used in medium and heavy-duty trucks, construction vehicles and other off-road vehicles.

Heavy-Duty Battery (Dry-Cell)

A dry-cell battery used in low-to-medium-drain applications, such as flashlights and radios. A lower-priced alternative to an alkaline battery, it has less capacity and is unsuitable for high-drain applications.

Hertz (Hz)

A unit of frequency equal to one cycle per second.

Hot-Cranking Amps (HCA)

A rating similar to CCA that is used to define the current output of a storage battery at 80°F (27°C). These inflated ratings should not be confused with CCA.

Hourly Rate

See amp-hour

Hydrometer

An instrument — normally a mechanical float type device but can be electronic — used to determine the state of charge of a battery by measuring the specific gravity of its electrolyte.

hertz

current

IEC

International ElectroChemical Commission

Immobilized Electrolyte

An electrolyte made motionless by use of a gel additive or AGM separator. See also Gel-Cell Battery and Recombinant.

Impedance (Z)

The total opposition that a battery offers to the flow of alternating current. Impedance is a combination of resistance and reactance.

Initial Drain

The current that a cell or battery supplies when first placed on load. Also referred to as starting drain.

Insulator

A material — such as rubber, some plastics and glass — that is highly resistant to conducting electricity.

Internal Resistance (Ri)

The opposition to direct current flow within a battery, which causes a drop in closed-circuit voltage proportional to the battery's discharge rate.

International ElectroChemical Commission (IEC)

A worldwide organization that establishes standards in the electrical and electronic fields.

Key-Off Drain

An electrical discharge, such as that caused by a vehicle computer memory or alarm system, that draws power from the car battery when the vehicle is not running. See also Drain.

Kilowatt (kW)

One thousand watts.

kilowatt

Lead-acid Battery

A storage battery with an active material of lead and lead peroxide and with an electrolyte solution of water and sulfuric acid. Maintenance-free, low-maintenance and gel-cell batteries are types of lead-acid batteries.

LeClanche

A carbon-zinc battery with slightly acidic electrolyte consisting of ammonium chloride and zinc chloride in water.

Li-Ion

lithium-ion battery

Lithium Battery

Lithium primary batteries are non-rechargeable batteries used in devices requiring long life and low, steady power, such as digital watches, computers and smoke detectors. Some types of lithium batteries are specifically designed for applications with high power requirements, such as wireless microphones and flash units.

Lithium-Ion Battery (Li-Ion)

A rechargeable battery with a very high capacity for its size and weight compared to other rechargeable batteries. It is used in portable devices such as laptops, cellular phones and camcorders.

Load

A circuit's built-in resistance — e.g., the starting motor, headlights or resistor — that discharges the battery when operating.

Load Tester

An instrument that discharges a battery using an electrical load while measuring voltage. It determines the battery's ability to perform under actual operating conditions.

Low-Maintenance Battery

Normally a lead-acid battery, it may require periodic water addition under normal service conditions. A dual-alloy battery, it typically uses a low antimony lead alloy in the positive (+) grid and a calcium-lead alloy in the negative (-) grid.

MilliAmp

mAH

Milliamp-hour

Maintenance-Free Battery

A battery that does not require water addition under normal service conditions. Both positive (+) and negative (-) grids are made of lead/calcium.

Marine-Cranking Amps (MCA)

A rating that is used to define the number of amps that a lead-acid marine battery at 32°F (0°C) can deliver for 30 seconds and maintain at least 1.2 volts per cell (7.2 volts for a 12-volt lead-acid battery). This artificially high rating should not be confused with CCA.

MCA

marine cranking amps

Memory Effect

A condition that is created when a NiCad or NiMH battery is partially discharged and recharged repeatedly, causing a loss of capacity.

MilliAmp (mA)

One one-thousandth of an amp

Milliamp-hour (mAH)

One one-thousandth of an amp-hour

Miniature Battery

A button- or coin-shaped battery — i.e., a button cell or coin cell — with a diameter greater than its height. The term miniature is also used to describe batteries made up of miniature cells.

Multimeter

Also known as a volt-ohm-meter (VOM), it is an instrument designed to do a variety of electrical testing, including voltage, amperage and resistance.

Negative (-)

Normally refers to the negative (-) battery terminal, which is the point from which electrons flow during discharge. The negative (-) terminal cap or cable is typically black, designating negative (-). See also Ground.

Negative (-) Plate

The negative (-) electrodes of a battery composed of "spongy" lead on a grid. See also Active Material.

NiCad

nickel-cadmium battery

Nickel-Cadmium Battery (NiCad)

A form of rechargeable battery used in portable devices such as camcorders, cell phones, cordless phones and power tools. Compared to nickel-metal-hydride and lithium-ion batteries, it can provide a higher constant discharge rate but has a lower capacity.

Nickel-Metal-Hydride Battery (NiMH)

A form of rechargeable battery used in portable devices such as camcorders, cell phones, cordless phones and laptops. It provides a higher capacity than a nickel-cadmium battery but is designed to perform at a lower discharge rate.

NiMH

Nickel-metal-hydride battery

Nominal Voltage

The rated voltage of a battery

OCV

open-circuit voltage

Ohm

The unit of measure for resistance within an electrical circuit. Its symbol is the Greek letter omega.

Ohmmeter

An instrument used to measure resistance in an electrical circuit

Ohm's Law

An equation — E (Volts) = I (Current) x R (Resistance) — that expresses the relationship between volts, amps and ohms in an electrical circuit with resistance.

Open Circuit

A circuit that has a broken or interrupted path, preventing current flow

Open-Circuit Voltage (OCV)

The no-load voltage of a cell or battery measured with a voltmeter. See also Closed-Circuit Voltage

Overcharging

The forcing of current through the battery after it is fully charged. Overcharging reduces service life and can damage the battery.

Parallel Circuit

A circuit in which the current has more than one path to follow. In this configuration, two batteries of equal rating are wired together positive (+) to positive (+) and negative (-) to negative (-). In parallel, the RC (Reserve Capacity) and CCA (Cold Cranking Amps) double while the voltage remains the same as the weakest individual battery.

Photovoltaic

Of, relating to or utilizing the generation of a voltage when radiant energy falls on the boundary between dissimilar substances, such as two different semiconductors.

Plate

A composite of a grid framework and the chemical active material. See Positive Plate and Negative Plate.

Polarity

The particular state of a battery terminal, either positive (+) or negative (-)

Polarization

The electrical potential reduction of electrodes, typically arising from prolonged or rapid discharge of the battery

Positive (+)

Normally refers to the positive (+) battery terminal, which is the point to which electrons in the external circuit flow during discharge. Sometimes the positive (+) terminal cap or cable is red, designating positive (+)

Positive (+) Plate

The positive (+) electrodes of a battery composed of lead peroxide on a grid. See also Active Material

Potential Difference

Voltage or electromotive force (EMF)

Power

The rate at which work is done. Power is measured in watts. P (Power) = E (Voltage) x I (Current)

Primary Battery

A cell or battery designed to deliver its rated capacity once and then be discarded; it is not designed to be recharged. Primary batteries include alkaline, heavy-duty and general-purpose batteries

resistance

Rapid Charge

The charging of a battery, typically a NiCad, to its capacity in a short period of time

Rapid-Charge Battery

A battery pack that is designed to accept a high amount of current in a short amount of time, such as a radio-control battery

Rate Sensitivity

Typically refers to battery performance under various discharge loads with operating voltage being the defining characteristic

Rated Capacity (Dry Cell)

The average capacity delivered by a cell or battery on a specified load and temperature to a cutoff voltage, as designated by the manufacturer. Rated capacity is usually determined by an accelerated test approximating the cell or battery's capacity in typical use.

Rated Capacity (Flooded)

The CCA, RC or amp-hours that a battery can deliver at a given rate of discharge, end voltage and temperature. These ratings are often displayed on the outside of the battery

reserve capacity

Rechargeable Battery

A cell or battery capable of being recharged. Refers to secondary batteries

Recharging

See charging

Recombinant

The process in which the oxygen formed at the positive (+) plate diffuses to the negative (-) plate, reacts with the lead and suppresses water loss. In a recombinant (immobilized electrolyte) chemistry battery, gassing is recombined within the sealed battery so that water addition is unnecessary

Reconditioning

See Conditioning

Rectifier

Device that changes alternating current to direct current

Rectify

To convert alternating current into direct current

Reserve Capacity (RC)

BCI defines it as "the number of minutes a new, fully-charged battery at 80ºF (27ºC) can be discharged at 25 amps and maintain a voltage equal to or higher than 1.75 volts per cell" (i.e., 10.5 volts for a 12-volt battery). This rating represents the time the battery will continue to operate essential accessories in the event of a charging system failure.

Resistance (R)

The opposition to the free flow of current in a circuit. Resistance is measured in ohms. See also Internal Resistance

Resistor

A device, with electrical resistance, that is used in an electrical circuit for current control and efficient operation.

Reversal

See Reversed Polarity

Reversed Polarity

The changing or reversing of the normal polarity of a battery, which commonly occurs when battery cables or charging cables are connected backwards

internal resistance.

Sealed Battery

A maintenance-free battery with nonremovable vent caps

Secondary Battery

Any battery that is designed to be recharged, such as lead-acid, NiCad and nickel-metal-hydride batteries

Self-Discharge

The discharge that occurs in a battery while it is not in use. The higher the temperature, the greater the rate of self-discharge

Self-Discharge Rate

The rate at which a cell or battery loses its capacity when standing idle

Separator

An insulative divider between the positive (+) plates and negative (-) plates of an element that allows the flow of current to pass through it and prevents positive (+) and negative (-) electrodes from touching and creating a short circuit. Interstate's lead-acid batteries generally use polyethylene separators

Series Circuit

A circuit in which the current has only one path to follow. In this configuration, two batteries of equal rating are wired together positive (+) to negative (-). In series, the battery voltage increases while the RC and CCA remain the same as the weakest individual battery

Series/Parallel Circuit

A circuit in which some of the terminals are connected in series to increase total voltage, and some are connected in parallel to increase total capacity. The amount of voltage and capacity depends on the exact number of series and parallel connections

Service Life

The length of time a battery can be used in a given application

Shelf Life

The amount of time a cell or battery will retain a specified percent of its rated capacity, typically under ambient storage conditions. Interstate's superior rotation service ensures that batteries are fresh on the shelf

Short Circuit

An unwanted electrical connection between a negative (-) ground and a positive (+) source. A short circuit in a battery cell may be permanent enough to discharge the cell and render the battery useless

Silver-Oxide Battery

A small, nonrechargeable battery used in devices such as watches and calculators

SLI

Starting, Lighting, and Ignition - A battery primarily used to start a vehicle and to provide power for lights and accessories. SLI batteries include automotive, deep-cycle and heavy-duty commercial starting batteries.

Slow Charging

Charging at a rate of about 5-10% of a battery's rated capacity. Example: 50 AH battery x 10% = 5-amp charge

Smart Battery

A battery with internal circuitry designed to communicate information, such as capacity remaining, to the user or to other parts of the application's circuit

Smart Charger

A charger that fully discharges a NiCad battery and/or an NiMH battery before recharging it to prevent a memory effect from occurring

Solenoid

(1) A term used to mean coil or inductor. (2) A type of relay that switches the starter current "off" in an automobile after the engine engages

Specialty Battery

Any battery other than an SLI battery

Specific Gravity

In a lead-acid battery, the weight of sulfuric acid compared to the weight of an equal volume of pure water

Standby

A backup power supply. See also Float Charge and Uninterrupted Power Supply

Standby Time

The number of hours a cell phone can be left "on" and unused before its battery's capacity is depleted. See also Talk Time

Starting Battery

A starting-lighting-and-ignition battery (SLI) used to crank the engine or motor and power accessories while the motor/engine is running.

Starting-Lighting-and-Ignition Battery (SLI)

A battery primarily used to start a vehicle and to provide power for lights and accessories. SLI batteries include automotive, deep-cycle and heavy-duty commercial starting batteries

State of Charge

The condition of a battery in terms of rated capacity remaining at a given point in time. See also Open-Circuit-Voltage Chart, Specific-Gravity Chart and Depth of Discharge

Stratification

A condition in which the concentration of acid is greater at the bottom of the battery than at the top. Normally caused by continued undercharging.

Sulfation

The accumulation of lead sulfates on the plates of a lead-acid battery. When enough plate area has sulfated, the battery will not be able to provide enough current and will normally need to be replaced

Switch

A mechanical device used for opening and closing a circuit

Talk Time

The number of minutes that a cell phone can be used before its battery's capacity is depleted. See also Standby Time.

Temperature Cutoff

A device, such as a thermostat, that senses battery temperature and opens the battery circuit when the temperature reaches a certain point.

Terminal

A connection point on a device or component, e.g., a battery terminal.

Terminal Voltage

The voltage at the battery terminals

Trickle Charging

Charging at a very slow rate of 1-2 amps, this is typically used for smaller batteries — e.g., motorcycle, lawn and garden — or occasionally is erroneously used for keeping large automotive batteries fully charged when they are not in use.

Uninterrupted Power Supply (UPS)

It is a battery-powered system that provides standby power if the primary power is interrupted.

Unwanted Resistance

Any resistance — e.g., corrosion and inadequate connections — found in a circuit that is not designed into the circuit.

UPS

uninterrupted power supply

Valve-Regulated Lead-acid Battery (VRLA)

A lead-acid battery that is sealed with the exception of a one-way valve that opens to the atmosphere when the internal gas pressure in the battery exceeds the atmospheric pressure by a pre-selected amount. VRLA batteries are sometimes called recombinant batteries

Vented Battery

A battery in which the gaseous products of electrolysis and evaporation are allowed to escape into the atmosphere as they are generated. These batteries are commonly referred to as flooded batteries

Venting

When gas or electrolyte escapes through a valve or vent

Volt (E)

The unit of measure for electrical potential or pressure, which is also called electromotive force (EMF). Volts = Amps x Ohms

Voltage

Also called electromotive force (EMF), it is the electrical pressure that forces electron flow in a complete circuit

Voltage Drop

The net difference in the electrical potential (voltage) when measured across a resistance (ohms). Its relationship with current is described in Ohm's Law

Voltage Regulator

A device that limits the charging voltage in a circuit

Voltmeter

An instrument used to measure the voltage in a circuit or the state of charge of a battery by measuring its open-circuit voltage

Volt-ohm-meter (VOM)

multimeter

VOM

Volt-ohm-meter See Multimeter

VRLA

valve-regulated lead-acid battery

watt

Watt (W)

The unit of measure for electrical power. W = Amps x Volts.

Watt-Hour

The unit of measure for electrical energy. Watt-Hour = Watts x Hours.

impedance

Zinc Chloride

A chemistry used in some heavy-duty batteries.

Zinc-Air Cell

A dry-cell battery system that uses oxygen and catalyzed carbon as the cathode and zinc as the anode to produce electricity.

Finding Your Batteries

Battery Glossary