ACPI (Advanced Configuration and Power
Interface) - A specification that allows
the Operating System to control power
management. Hardware information is made
available to the operating system, and ACPI
turns peripherals on and off for improved
power management. ACPI also makes power
management available for notebook PCs and
allows the keyboard or mouse to bring the PC
out of sleep mode.
Aging - the irreversible loss of
capacity in rechargeable batteries.
Alternating Current (AC) - An
electrical current which changes or reverses
the direction of its flow. A notebook PC is
running on AC power when its power cord is
attached and plugged in.
Ampere, or Amp - The basic
unit of measurement for electrical current.
One volt flowing across one ohm resistance
will create a current of one Amp.
Amp Hours - A unit of measure for a
battery's storage capacity, this is
calculated by multiplying the current in
amperes by the time in hours of discharge.
For example, a battery rated at 100 amp
hours can dispense 20 amperes for 5 hours
(10 amps X 5 hours = 100 amp hours).
Battery - A device that stores energy
for later use. Most batteries consist of a
group of two or cells connected together
which transform chemical energy into
Cycle - The process of one complete
discharge and recharge for a rechargeable
Cycle Life - The number of times a
battery can be charged and discharged during
Direct Current (DC) - An electrical
current that flows in one direction only. A
notebook PC is running on DC power when it
is running on its battery.
Energy density - The amount of energy
stored in a unit of weight or volume,
expressed in watt hours per kilogram or watt
hours per liter.
Energy storage - The amount of
energy, expressed in watt hours, that is
stored in a battery or battery pack.
Fast Charge Time - Typical fast
charge time for a NiCd is 1 to 3 hours. The
fast-charger detects the state-of-charge and
switches to trickle charge when full-charge
Full Charge Capacity (FCC) - the
actual capacity of a battery over time,
expressed as a percentage of the initial
rated capacity of the battery.
Lithium Ion, or Li-Ion - A
rechargeable battery technology introduced
in 1991 and currently used in notebook PCs.
Li-Ion batteries are lighter, last longer,
and discharge slower than previous battery
Memory effect - A phenomenon
associated with some rechargeable batteries
that sometimes occurs when the battery is
recharged without first being fully
discharged. Memory effect shortens battery
life and reduces run-time between charges.
Ohm - A unit of electrical
resistance. One volt flowing across one ohm
resistance will create a current of one Amp.
Self discharge - The rate at which a
battery loses energy when not in use. This
can be expressed as a percentage loss per
day or month.
Smart battery - Also known as an
'intelligent battery.' A battery pack
containing internal circuitry that enables
communication between the battery and the
Volt - The unit of measurement of
electrical potential. One volt is the amount
of electrical potential between two points
on a conductor carrying a current of one
ampere while one watt of power is dissipated
between the two points. A single cell is two
Watt - A unit used to measure total
electrical power. It is calculated by
multiplying amps by volts.