Power-Sonic Sealed Lead Acid Batteries - Technical Manual - Manual (Page 26)

Glossary
Active Material
The active electro-chemical materials used in the manufacture of
positive and negative electrodes.
Ambient Temperature
The prevailing surface temperature to which a battery is exposed.
Ampere
Unit of measurement for electric current.
Ampere-Hour
The product of current (amperes) multiplied by time (hours).
Used to indicate the capacity of a battery. Also Amp. Hr. or A.H.
Battery
Two or more cells connected together, most typically in series.
C
Used to signify a charge or discharge rate equal to the capacity
of a battery divided by one hour. Thus C for a 1600 mAh battery
would be 1.6 A. C/5 for the same battery would be 320 mA and
C/10 would be 160 mA.
Capacity
The electrical energy available from a cell or battery expressed in
ampere-hours.
• Available capacity: ampere-hours that can be discharged
from a battery based on its state of charge, rate of
discharge, ambient temperature, and specified cut-off
voltage.
• Rated capacity (“C”): the discharge capacity the
manufacturer states may be obtained at a given discharge
rate and temperature.
• Capacity fade: the loss of capacity due to inadequate
recharging.
Cell
The basic building block of a battery. The nominal voltage of a
lead-acid cell is 2 volts.
• Cell reversal: the act of driving a cell into reverse polarity by
excessive discharge.
• Primary cell: cell or battery that can be discharged only
once.
• Secondary cell: the process is reversible so that charging
and discharging may be repeated over and over.
Charge
The conversion of electrical energy to chemical energy; the
process which restores electrical energy to a cell or battery.
• Charge retention: a battery’s ability to hold a charge. It
diminishes during storage.
• Charge acceptance: quantifies the amount of electric
charge that accumulates in a battery.
• Float charge: maintains the capacity of a cell or battery by
applying a constant voltage.
Charge (Continued)
• Trickle charge: maintains the capacity of a cell or battery by
applying a small constant current.
• Charge equalization: brings all of the cells in a battery or
string to the same state of charge.
Closed Circuit Voltage Test
A test method in which the battery is briefly discharged at a
constant current while the voltage is measured.
Cutoff Voltage
The final voltage of a cell or battery at the end of charge or
discharge.
Cycle
A single charge and discharge of a cell or battery.
Deep Cycle
A cycle in which the discharge continues until the battery
reaches it’s cut-off voltage, usually 80% of discharge.
Direct Current (DC)
The type of electrical current that a battery can supply. One
terminal is always positive and the other always negative.
Discharge
The process of drawing current from a battery.
• Deep Discharge: the discharge of a cell or battery to
between 80% and 100% of rated capacity.
• Depth of Discharge: the amount of capacity - typically
expressed as a percentage - removed during discharge.
• Self Discharge: the loss of capacity while stored or while
the battery is not in use.
• Self Discharge Rate: the percent of capacity lost on open
circuit over a specified period of time.
Drain
The withdrawal of current from a battery.
Electrode
Positive or negative plate containing materials capable of
reacting with electrolyte to produce or accept current.
Electrolyte
Conducts ions in a cell. Lead acid batteries use a sulfuric acid
solution.
End of Charge Voltage
The voltage reached by the cell or battery at the end of charge,
while the charger is still attached.
Energy Density
Ratio of battery energy to volume or weight expressed in watt-
hours per cubic inch or pound.