AMPERE HOUR The product resulting from multiplication of amperes flowing by time of flow in hours, e.g., a battery supplying 10 amperes for 8 hours gives 80 ampere hours. See note under "Volt?' for more complete explanation of current flow.

BATTERY Two or more electrical cells electrically connected in series so that combination furnishes current as a unit.

BATTERY CHARGER See rectifier.

BATTERY TERMINALS The battery terminals are the means to access the stored electrical energy in the battery. There is a minimum of one positive and one negative terminal.

CAPACITY The number of ampere hours a battery can supply at a given rate of current flow after being fully charged, e.g., a battery may be capable of supplying 10 amperes of current for 8 hours before it is exhausted. Its capacity is 80 ampere hours at the 8 hours rate of current flow. It is necessary to state the. rate of flow, since same battery if discharged at 20 amperes would not last for 4 hours but for a shorter period, say 3 hours. Hence, its capacity at the 3 hour rate would be (3 x 2O = 60) ampere hours.

CASE The container in which the battery cells are housed.

CELL The battery unit, consisting of an element complete with electrolyte, in its jar with cover. Lead acid battery cells are nominally 2-volts. Two volts is the minimum nominal voltage for a lead acid cell.

CHARGE Passing direct current through a battery in the direction opposite to that of discharge, in order to put back the energy used on discharge.

CHARGE RATE The proper rate of current to use in charging a battery from an outside source. It is expressed in amperes and varies for different sized cells.

CORROSION The attack of metal parts by acid from the electrolyte; it is the result of lack of cleanliness.

COVER The cover forms a lid on each individual cell. It is usually tongue and groove flange for a more effective seal.

CYCLE One charge and discharge.

DENSITY Specific gravity.

DISCHARGE The flow of current from a battery through a circuit, opposite of "charge."

DISCHARGE RATE The current flow measurement for discharge or charge of a battery rated in Amps.

DRY Term frequently applied to cell containing insufficient electrolyte. Also applied to certain conditions of shipment of batteries.

ELECTROLYTE The conducting fluid of electro-chemical devices; for lead-acid storage batteries it consists of about two parts of water to one of chemically pure sulphuric acid, by weight.

ELEMENT Positive group, negative group and separators.

EQUALIZATION The result of circulation and diffusion within the cell which accompanies charge and discharge. Difference in capacity at various rates is caused by the time required for this feature.

EQUALIZING Term used to describe the making uniform of varying specific gravities in different cells of the same battery, by adding or removing water or electrolyte.

EVAPORATION Loss of water from electrolyte from heat or charging. Finishing Rate. The current in amperes at which a battery may be charged for twenty-four hours or more. Also the charging rate used near the end of a charge when cells begin to gas.

FORMING Electro-chemical process of making pasted grid or other plate, types into storage battery plates.

FOREIGN MATERIAL Objectionable substances.

FRESHENING CHARGE A charge given to a battery which has been standing idle, to keep it fully charged.

GASSING The giving off of oxygen gas at positive plates and hydrogen at negatives, which begins when charge is something more than half completed-depending on the rate.

GRAVITY See "specific gravity”.

GRID The metal framework of a plate, supporting the active material and provided with a lug for conducting the current and for attachment to the strap.

GROUP A set of plates, either positive or negative, joined to a strap. Groups do not include separators.

HYDROMETER A glass barrel enclosing a hydrometer and provided with a rubber bulb for drawing up electrolyte.

JAR See “Case”.

LEAD BURNING A term used to describe the operation of joining two pieces of lead by melting them at practically the same instant so they may run together as one continuous piece. Usually done with mixture of oxygen and acetylene gases or LPG and oxygen gases. This process is used to join the plates to the bus-bar and the bus-bar to the terminals. It is also used to connect cell to cell in some applications.

LUG The extension from the top frame of each plate, connecting the plate to the strap.

MAXIMUM GRAVITY The highest specific gravity which the electrolyte will reach by continued charging, indicating that no acid remains in the plates.

MUD Loosened or worn out particles of active material fallen to the bottom of cells, sometimes referred to as sediment.

NEGATIVE The terminal of a source of electrical energy as a cell, battery or generator through which current returns to complete circuit. Generally marked "Neg".

OHM The unit of electrical resistance. The smaller the wire conductor the greater is the resistance. Six hundred and sixty-five feet of No. 14 wire (size used in house lighting circuit) offers I ohm resistance to current flow.

OVER-DISCHARGE The carrying of discharge beyond proper cell voltage; shortens life if carried far enough and done frequently.

PASTE The mixture of lead oxide or spongy lead and other substances which is put into grids.

PLATE The combination of the cast alloy grid, pasted with active material of lead oxide, sulphuric acid and other ingredients. The positive plate reddish brown and negatives slate gray.

POLARITY An electrical condition. The positive terminal (or pole) of a cell or battery or electrical circuit is said to have positive polarity; the negative and negative polarity.

POSITIVE Generally marked "Pos" or + on top of the battery next to the terminal. This denoted positive polarity.

POST The battery post is what delivers the electrical energy from the internal bus-bar to the outside terminal. This is usually cast from lead alloy.

POTENTIAL DIFFERENCE Potential difference is the difference in voltage levels between two sources. If a battery charger connected to a battery has a higher voltage than the battery then current will flow into the battery from the charger.

RAPS Remote Area Power Supply.

RATED CAPACITY This is the capacity in ampere hours of a given size battery when discharged to a safe voltage. Rectifier. Apparatus for converting alternating current into direct current. Also called a battery charger.

RESISTANCE Material (usually lamps or wire) of low conductivity inserted in a circuit to retard the flow of current. By varying the resistance, the amount of current can be regulated. Also the property of an electrical circuit whereby the flow of current is impeded. Resistance is measured in ohms. Analogous to the impediment offered by wall of a pipe to flow of water therein.

RHEOSTAT An electrical appliance used to raise or lower the resistance of a circuit and correspondingly to decrease or increase the current flowing.

REVERSAL Reversal of polarity of cell or battery, due to excessive discharge, or charging in the wrong direction.

SEDIMENT Loosened or worn out particles of active material fallen to the bottom of cells; frequently called' "mud".

SEDIMENT SPACE That part of jar between bottom of the plates and top of container bridge.

SEPARATOR An insulator between plates of opposite polarity; usually of wood, rubber or combination of both. Separators are generally corrugated or ribbed to insure proper distance between plates and to avoid too great displacement of electrolyte.

SHORT CIRCUIT A metallic connection between the positive and negative plates within a cell. The plates may be in actual contact or material may lodge and bridge across. If the separators are in good condition, a short circuit is unlikely to occur.

SPECIFIC GRAVITY The density of the electrolyte compared to water as a standard. It indicates the strength and is measured by the hydrometer.

SULPHATE Common term for lead sulphate. (PbSO4).

SULPHATED Term used to describe cells in an under-charged condition, from either over- discharging without corresponding long charges or from standing idle some time and being self discharged.

SULPHATION Forming lead sulphate on the surface of the positive plate is a natural part of lead acid battery operation however this needs to be reconverted by the charge phase of the battery. If the battery is not fully charged then this lead sulphate can harden and crystalize. This blocks off part of the plate and locks up the acid needed in the electrolyte for battery operation. This will result in loss of capacity and if not corrected permanent damage to the battery.

TERMINAL Part to which outside wires are connected.

UPS Uninterrupted Power Supply.

VENT, VENT PLUG OR VENT-CAP Hard or soft rubber part inserted in cover to retain atmospheric pressure within the cell, while preventing loss of electrolyte from spray. It allows gases formed in the cell to escape, prevents electrolyte from spilling, and keeps dirt out of the cell.

VOLT The commercial unit of pressure in an electric circuit.Voltage is measured by a voltmeter. Analogous to pressure or head of water flow through pipes. NOTE. - Just as increase of pressure causes more volume of water to flow through a given pipe so increase of voltage (by putting more cells in circuit) will cause more amperes of current to flow in same circuit. Decreasing size of pipes is increasing resistance and decreases flow of water, so also introduction of resistance in an electrical circuit decreases current flow with a given voltage or pressure.

WATT The commercial unit of electrical power, and is the product of voltage of circuit by amperes flowing. One ampere flowing under pressure of one volt represents one watt of power.

WATT HOUR The unit of electrical work. It is the product of power expended by time of expenditure, e.g., 10 amperes flowing under 32 volts pressure for 8 hours gives 2560 watt hours.