BATTERY CHARGER
SHORT CORSE
PREPAIRED BY
NASIR GHAURI
A.M TSG
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COMPONEMTS OF D.C SYSTEM
i)
BATTERY
ii)
BATTERY CHARGER
iii)
D.C DISTRIBUTION BOARD
BATTERIES
TYPES OF BATTERIES
i)
PRIMARY BATTERIES
ii)
SECONDRY BATTERIES
PRIMARY BATTERIES
Non rechargeable cells known as Primary cells.
SECONDRY BATTERIES
Battery cells can be recharged because the chemical reaction that occurs
during discharge can be reversed by applying a reverse current into the
cell. The cell can be discharged and recharged many times (often many
thousand times) before it is degraded to the point where it can no longer
provide reliable service.
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LEAD-ACID BATTERIES
It is also called a ‘wet-cell’ or ‘flooded-cell’ battery because the
electrolyte is in a liquid form. They are vented batteries because the
charging process can produce gasses of hydrogen and oxygen which
needs to be able to escape from the confines of the battery case. In its
charged state the (positive plates) are lead peroxide, the (negative
plates) are lead, and the electrolyte is dilute sulphuric acid. As the cell is
discharged the plates are converted to lead sulphate and the electrolyte
becomes water. The chemical reaction looks like this
PbO2 + Pb + 2H2SO4 ↔ 2PbSO4 + 2H2 + ½O2
Sealed Lead Acid (SLA) Batteries
Type of lead acid battery which is more common because of the reduced
maintenance requirements. More correctly, Called a valve regulated leadacid battery, because they do have a valve to release internal gas build up
which can result from overcharging. The electrolyte has been jellified
making the battery more resistant to extreme temperatures, vibration and
shock. This is also why they are sometimes called ‘Gel Cells’. They also
have calcium included in the plate construction which reduces the gassing
effects, minimising loss of electrolyte.
CHEMICAL COMPOSITION OF LEAD-ACID BATTERIES
i)
POSITIVE PLATE
PbO2
ii)
NAGETIVE PLATE
Pb
iii)
SULPHURIC ACID AS AN
H2SO4
ELECTROLYTE
CHEMICAL REACTION LEAD-ACID BATTERIES
PbO2 + Pb + 2H2SO4 ↔ 2PbSO4 + 2H2 + ½O2
Lead acid batteries have reduced life expectancy if they are left in a
discharged condition. Ordinarily they do not deal well with deep
discharge cycles
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CHARGING REQUIRMENTS OF BATTERIES
i)
INITIAL / AFTER CAPACITY TEST CHARGING
ii)
FLOAT CHARGING
iii)
BOOST CHARGING
iv)
PERIODIC / EQUALIZING CHARGING
INITIAL / AFTER CAPACITY TEST CHARGING
CHARGING RATE SHOULD BE MANTINED AS PER
MANUFACTURER INSTRUCTION WHICH IS APPROXIMATLLY 7%
OF AMPER HOUR CAPACITY
FLOAT CHARGING
CHARGING VOLTAGE THAT COUNTERACTS SELF DISCHARGE
A battery is said to float when charging voltage is slightly greater than
the open circuit voltage of the battery.
Note:
Charge batteries continuously at the float voltage
recommended by the manufacturer
BOOST VOLTAGE
AFTER DISCHARGE, THE BATTERY IS RECHARGED AT HIGHER
CHARGING RATE
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Condition For Boost Charge
1.
Following heavy discharge.
2. If specific gravity (corrected for temperature) of any cell is more
than 10 points
(0.010) below the full charge value while on float.
3. If the voltage of any cell is more than 0.04 volt below the average cell
voltage when the battery is on float.
4. If the level in any cell or cells falls at or near the minimum fill line a
lot of distilled water must be added to restore the level to the maximum
fill line. If this condition occurs, an equalizing charge must be
performed to
restore specific gravity.
PRIODIC / EQUALIZING CHARGE
CORRECTIVE TYPE OF CHARGE THAT BRINGS ALL CELLS UP TO
FULLY CHARGE CONDITION.
IT IS APPLIED AFTER INITIAL CHARGE, CAPACITY TEST AND A
SPACIFIC PERIOD. THE VOLTAGE LEVEL IS KEPT EQUIVALENT
TO THAT OF BOOST CHARGE.
The purpose of the equalizing charge is to ensure that every plate in
every cell is brought with certainty to a state of full charge by a slight
overcharge.
TEMPERATURE
Higher temperatures reduce the operational life. Lower temperatures
reduce the available capacity. If the battery operating temperature is
different from 77°F, a correcting factor is to be applied to capacity
value taking into account discharge time. (Reference IEEE-450-2010)
The permissible operating temperature range is 5°F to 130°F, The
recommended operating temperature range is 68°F to 77°F. This will
maximize life and minimize maintenance.
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Operating Temperature Recommended Applied Float Voltage VPC
(Haze Battery)
Temperature
Voltage Range
0-9
10-14
15-19
20-24
25-29
30-34
35-40
2.33 - 2.35
2.30 - 2.33
2.27 - 2.30
2.27 - 2.30
2.25 - 2.27
2.23 - 2.25
2.21 - 2.23
All technical data relates to a rated temperature of 77°F( 25°C).
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ELECTROLYTE
Electrolyte is a diluted sulfuric acid. The nominal S.G. of the electrolyte
at 77°F. The maximum deviation is +/-.01g/cm3.Higher temperatures
will decrease electrolyte density, while lower temperatures increase
electrolyte density. The correction factor is .001 for each 3°F. For each
3°F over 77°F, add .001 to the S.G. reading. For each 3°F below 77°F,
subtract .001 from the S.G. reading.
Storage
Store the batteries in a dry, clean and preferably cool and frost-free
location. Do not expose the cells to direct sunlight.
►Note: Failure to observe these conditions may result in reduced
capacity and service life as well as voiding the battery warranty.
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BATTERY CHARGER
A DEVICE WHICH IS USED TO MAINTAIN BATTERY AND LOAD
UNDER ALL OPERATING CONDITIONS
PARTS OF BATTERY CHARGER
i)
ii)
iii)
iv)
v)
vi)
vii)
viii)
MAIN TRANSFORMER
BRIDGE RECTIFIRE
LC FILTER
BLOCKING DIODE
FREE WHEELING DIODE
LOAD VOLTAGE CONTROL CIRCUIT
FIRING CIRCUIT
PROTECTION CIRCUIT
Main Transformer
Main purpose of transformer is isolation between AC to DC and
also used to reduce voltage
Bridge Rectifier
Converts A.C into D.C
Half-wave
Rectification
0.405
ratio – η
Centre-tap
0.81
Bridge
0.81
3Ø Bridge
0.968
LC Filter
Purpose of LC Filter is Harmonic suppression
Blocking Diode
Used to protect from Reverse Power
Free Wheeling Diode
Used for Reverse Recovery
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DRAWINGS
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D.C DISTRIBUTION BOARD
HOLDS ALL PROTECTIONS, CONTROLS AND OPERATIONS
TYPE-A
Battery
Battery
Charger
Distribution
Board
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TYPE-A
Battery
Battery
Charger
Distribution
Board
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│
█Coupler C.B
│
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Battery
Battery
Charger
Distribution
Board
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