VRLA -Valve regulated lead acid battery.
SLA -Sealed Lead-acid
CCV -Closed - circuit voltage.
OCV -Open - circuit voltage
WPC -Watts per cell.
Pb -Chemical symbol for lead.
UPS -Uninterruptible power supply
Ah -Amp hour. The unit of battery capacity
DOM -Date of manufacture.
EOD -End of discharge.
VPC -Volts per cell.
Nc -Number of cells.
Vf -Float voltage.
Vs -Starting voltage.
Iav -Average current.
Sg -Specific gravity
cAn -Is the defined capacity of the battery to
the ¡®n¡¯Time period.
20hr Rate -The capacity a battery will deliver
A Plastic material largely used for the case
and cover of batteries.
The substance which electrochemically reacts
in the electrode of batteries. Lead-acid batteries
adopt lead dioxide for the positive electrode
and spongy lead for the negative electrode.
Average temperature in the vicinity of the
The capacity actually available from a cell/battery.
The available capacity is the capacity when it
discharges at a specified hour rate, and expressed
in hour rate and Ah.
A type of battery terminals, to which lead
wires are connected with bolts.
The built-in thermostat is a reset table switch
built in a battery for temporarily cut off the
battery circuit when the temperature of the battery
exceeds a preset values or when the battery charge/discharge
at a higher rate than predetermined.
The electric capability of a battery. It usually
means ampere-hour capacity expressed in Ah or
The minimum battery unit which composes a storage
battery. Nominal voltage of the cell of the lead-acid
battery is 2V.
The operation of supplying a battery with a DC
current from an external power source to have
the electrode active material conduct chemical
reactions then to store electric energy as chemical
energy in the battery.
Test of batteries to check whether or not they
are adequately recharged after discharge.
General term for ampere-hour efficiency and watt-hour
eficiency. In many cases, however,it means the
CONSTANT CURRENT CHARGE
A method of charging: to charge a battery with
a constant current.
A charge or discharge current rate expressed in
A or mA.It is numberically the same as the hour
rate capacity of a battery expressed in Ah of
the rated capacity.
CUT-OFF VOLTAGE OF DISCHARGE
The terminal voltage of a battery at which discharging
should be discharging should be discontinued.
This voltage depends on discharge current, type
of electrodes and construction of battery.
The number of charge/discharge/rest cycles a cell/battery
can provide. Cycle life is usually expressed by
the number of cycles available before duation
of discharge decreases to a half of the initial
DEPTH OF DISCHARGE
A value to express the state of discharge of a
battery. The depth of discharge is generally expressed
by the ratio of discharge amount to rated capacity
of the battery.
To draw off the electric energy stored in a cell/battery.
The term to express the magnitude of discharge
current. When assuming discharge current and time
to discharge cut-off voltage t hours, this discgarge
is called t-hour rate(tHR) discharge, and the
current is called t-hour rate diacharge current.
When time t is minutes instead of hours, tMR is
Test of batteries in ordinary use including charge,
discharge and rest.
The medium which serves to conduct ions in the
electrochemical reactions in batteries. The lead-acid
battery adopts diluted sulfuric as the electrolyte.
Energy available per unit Approx. mass or unit
volume of a cell/battery. Energy desity is expressed
in Wh/kg or Wh/l.
The system in which a constant voltage is continuously
applied to a battery connected to a rectifier
in parallel with a load to maintain the battery
in charged state: on occurrence of power failure
or load variation, the battery supplies power
to the load without any short break.
GAS RECOMBINATION ABILITY
Capability of a battery to recombine (or absorb)
internally generated oxygen gas at the negative
plate. The greater this capability is, the larger
the available charge current.
HIGH RATE DISCHARGE
A very rapid discharge of a battery. (in many
cases it means discharging at approx.1 CA or higher
The pressure within a sealed battery. Internal
pressure of a battery is increased by oxygen gas
which is generated from the positive plate at
the end of charging.
The resistance within a battery; it is the total
of individual resistances of the electrolyte and
the positive and negative plate. Internal resistance
is simply measured with the current four-terminal
method(1,000Hz) and expressed in the composite
value of resistance component and capacitor component.
Touching of the positive and negative plates within
The time period until a cell/battery loses its
Low maintenance means that no watering norequalizing
charge is requireed in operating batteries.
A circuitry designed to discontinue discharge
of a battery at a predetermined voltage level.
The matallic pieces which are attached to a SLA
battery as the terminals.
A phenomenon where a temporary drop of discharge
voltage is observed during deep discharge of an
alkaline rechargeable battery which has been subjected
to shallow charge/discharge. Cycles or trickle
charging over long time.
The battery electrode into which a current from
the external circuit flows during discharging.
The negative plate has lower electric potential
than the positive plate to the electrolyte. The
negative plate is incorporated with connection
parts such as the electrode pole.
A nominal value of capacity of a cell/battery,
which is a measure of electric capability. Rated
capacity is rather approximate compared with rated
A nominal value to indicate the voltage of a cell
battery. Generally, nominal voltage value of a
battery is somewhat lower than its electromotive
force. Nominal voltage of the lead-acid battery
is 2.0 V per unit cell.
OPEN CIRCUIT VOLTAGE
Measured voltage of a cell/battery which is electrically
disconnected from the external circuit.
Continuted charging of a fully charged cell/battery.
With batteries which require watering, overcharge
causes electrolysis of water, resulting in rapid
decrease of electrolyte. Generally, overcharge
adversely influences battery life.
Discharge of a battery to a voltage below a predetermined
Simultanous charging of two or more batteries
connected in parallel. In cyclic use of batteries,
specifically, the parallel charge tends to cause
an imbalance in charge state among the batteries,
which may shorten their service life.
A plastic material which is often used for the
case and cover of batteries.
The battery electrode from which a current flows
to the external circuit during discharging. The
positive plate has higher electric potential than
the negative plate to the electrolyte. The positive
plate is incorporated with connection parts such
as the electrode pole.
QUICK CHARGE(RAPID CHARGE)
Charging in a short time with a large current.
The stated capacity of a battery; namely, the
ampere-hour amount can be drawn from the battery
in fully charged state at a specified temperature,
at a specified discharge rate, and to a specified
cut-off voltage. The symbole CN may be used to
express the rated capacity of N-hour rate.
The rechargeable battery is a system comprising
two different electrodes and ion-conductive medium,
which is capable of converting chemical energy
to electric energy, and vice versa. It is also
called a secondary battery.
REFRESH CHARGE(AUXILIARY CHARGE)
Charging ogf a battery mainly to compensate for
its self discharge.
Residual capacity of a battery after partial discharge
or after storage for long time.
A method to control flowing electrolyte in a battery
with the retainer mat,etc..
Charging of a battery with its polarity reversed.
Namely, the battery discharges.
Reduction in capacity of a battery while no current
is draw by the external circuit. Self discharge
depends on temperature: amount of discharge approximately
doubles by each (10¡ãC) rise of ambine temperature.
SEALED LEAD-ACID BATTER(SLA BATTERY)
Valve-regulated lead-acid battery.
A porous or microporous liquid-absorbent material
which is installed between the battery electrodes
for preventing short-circuit, securing the separation
of the electrodes and retaining electrolyte. The
separator should be resistant to oxidation and
chicals; it should excel in electric insulation
and liquid-retention;and it should not disturb
diffusion of the electrolyte and ionic conduction.
General term of constant stand-by battery systems.
Batteries are kept charged by trickle/float method
at all times in preparation for unforeseen power
TERMINAL VOLTAGE AT DISCHARGE
The voltage of a battery during discharge.
Such phenomena as an excessively high set-up voltage
in constant-voltage charging of a battery and
a very high battery temperature cause charge current
to increase,which than raises the termperature
further:this vicious cycle is called thermal runaway,which
may,in the worst case,result in breakage of the
battery due to heat.
To charge a battery in the state of disconnection
from the load to compensate for its self discharge.
The service life of a battery in the trickle use.
Usually,the trickle life is the time expressed
in years before the dischargeable time of the
battery decreases to a half of the initial value.
Abbreviation of Underwriters Laboratories Inc.
in USA. The UL establishes various safety standards,
and performs official recognition of material,parts
UPS(Uninterruptible Power Supply)
Equipment or system which is automatically connected
to the load to supply power if the main power
VALVE(ONE WAY VALVE)
a valve on each battery which automatically releases
gas from the battery when internal pressure of
the battery exceeds a predermined value:it prevents
breakage of the battery due to excessive internal
pressure caused by the gas generated by charging
or other reasons. The valve also serves to prevent
outside air from entering batteries.