Active Material
The structure of lead compounds that produce and store electrical energy within a lead-acid battery.

Unit of electrical current strength. Abbreviated as “A” or “Amp”

Ampere-hour (Amp-hour)
Time indication on the ability of a battery to deliver a certain amount of current.



Battery Polarity
A battery has two poles; the positive and the negative pole. The positive pole is usually marked POS, P, or +, while the negative pole is usually marked NEG, N or -.

Base Hold Down
Specific container design with holding hole or cut at the outer bottom side to assure a firm position of the battery in the car.

Base Hold Down type



The amp-hours that the battery deliver at a specific discharge rate and temperature. The capacity of a battery is affected by a number of factors such as: active material weight, density of active material, adhesion of active material to the grid, quantity, design and dimension of the grid, plate spacing, separator design, the quantity of electrolyte and its specific gravity level, grid alloys, final limiting voltage, discharge rate, temperature, internal and external resistance, lifetime of the battery.

The electrochemical current-producing units in a battery, consisting of a set of positive plates and a set of negative plates, separate by separators, and filled with electrolyte. For automotive and motorcycle batteries (specifically in lead-acid battery), there are 6 cells in each 12 volt battery.

Cell lay-out

Central Gas Outlet/Central Venting
A component for centrally drawing off gases formed in the battery via a gas duct (flue) in the battery cover

An electrical circuit is the path followed by a flow of electrons. A closed circuit is a complete path. An open circuit has a broken or disconnected path.

Cold Cranking Amps (CCA)
CCA is the cranking ability of battery. It shows the number of amps a battery can support for 30 seconds at the temperature of 0°F or equals to -18°C, and maintaining the voltage of at least 7.2 V for the 12 volt battery. For example: a 12 V battery with 375 CCA, means the battery will provide 375 amps for 30 seconds at 0 degree before the voltage falls until at least 7.2 V.

In a battery, one discharge plus one recharge equals to one cycle.



When a battery is delivery current, it is said to be discharging.



A Sulfuric Acid solution, acts as the current conductor through the ions movement between the positive and negative plates.



Initial electrical charging for converting the active material into the charged state.



The Lead Alloy framework, supporting the active material of a battery plate, and conducts the current.

The reference potential of a circuit. In automotive use, the result of attaching one battery cable to the body or frame which is used as a path for completing a circuit in lieu of a direct wire from a component. Today, over 99% of autos use the negative terminal of the battery as the ground.



A measurement tool to find out the specific-gravity of the electrolyte in a flooded battery.



A technique applied in the rechargeable battery, in the conservative and low maintenance batteries. The Lead oxide electrode is separated by an electrolyte of sulfuric acid.

Load tester
An instrument that draws current (discharges) from a battery using an electrical load while measuring voltage. It determines the battery’s ability to perform under actual discharge conditions.



Maintenance Free
A battery that normally requires no watering service during its lifetime of use.



An Electrode consisting of the active material and conductive carrier.

The application process of active material pastes to lead grids.

Electrical term for describing the charge or voltage relationship between two electrodes.

Positive Plates
Consist of the grid and the active material from which current flows to the external circuit when the battery is discharging.

Purified water
Distilled or demineralized water for compensating the electrolyte losses in batteries requiring maintenance.



Rated Capacity
The ampere hours of discharge that can be removed from a fully charged secondary cell or battery, at a specific constant discharge rate at a specified discharge temperature and at specified cut off voltage.

Reserve Capacity (RC)
RC is the battery’s ability to sustain a minimum stated electrical load; defines in the number of minutes a battery at 80°F (equals to 27°C) can be discharged at 25 amps, and maintain a voltage of 10.5 V for 12 V battery.

Enforcing a fully-charged state from any charged state.



A certain material (wood, paper, porous plastic, porous rubber, etc.) used between the positive and negative plates to prevent the physical contact that causes the electronic conduction.

SLI Battery
Starting, Lighting, and Ignition battery, a battery designed for conventional gasoline automobile. SLI battery is destined to provide a lot of current during starting, but then to be recharged immediately by the car’s alternator.

Self-discharging is a temperature-dependent permanent chemical reaction process at a cell’s or battery’s electrodes, without connection to the user.

Battery protection against vibration achieved through design measures and separator.

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

Specific Gravity (SP. Gr. Or SG)
Specific Gravity is a measure of the electrolyte concentration in a battery. This measurement is based on the density of the electrolyte compared to the density of the water and is typically determined by the use of a hydrometer. By definition, the SG of water is 1.0 and the SG of the sulfuric acid electrolyte when the battery is fully charged is 1.265 – 1.285.

Applied to the electrolyte; it is the layers of high gravity acid in the lower part of a cell (or a bottle). In a battery, this layer are out of the ordinary circulation touch of the electrolyte and thus of no use.

A term to describe any plate or cell or pole, whose active material contains of an appreciable amount of lead sulfate.

The formation of lead sulfate at the electrodes of a lead accumulator by recrystallization when the battery remains unused for a long time in deep discharge state.

Sulfuric Acid (H2SO4)
The principal acid compound of sulfur. Sulfuric acid of a high purity and in dilute form is the electrolyte of lead-acid storage cells.



Polarity-specific component on the battery to enable connection from the battery to external circuit.

Terminal type



A component that allow gasses to escape when inner pressure is too high, while preventing air from entering.

Venting Valve
Safety valve in the cell which opens in case of overpressure and closes again automatically when normal pressure has been restored

The practical unit of measurement of electro-motive force or potential difference required to send a current of one ampere through a resistnace of one ohm.

The potential difference exist between terminals of each battery or cell, or any two points of electrical circuit.

A tool or instrument for measuring voltage state.



The unit to measure electrical power. The rate of doing work, in moving electrons by, or against, an electrical potential. Formula: Watts=Amperes X Volts.

Filling in the water (demineralized water) to the battery electrolyte to replace any evaporative losses.