TITLE PAGE
CONSTRUCTION OF
12 VOLTS BATTERY CHARGE WITH 75 AMP HOURS BATTERY
BY
ENG/107150115 IGHOJOSEWE THOMPSON ONORIODE
A PROJECT WORK SUBMITTED TO THE DEPARTMENT OF
ELECTRICAL/ELECTRONICS ENGINEERING, AUCHI POLYTECHNIC, AUCHI, EDO STATE
IN PARTIAL FULFILLMENT OF THE REQUIREMENT FOR THE
AWARD OF NATIONAL DIPLOMA (ND) IN ELECTRICAL/ELECTRONICS ENGINEERING.
NOVEMBER 2017.
CERTIFICATION
This
is to certify that this technical report “Construction
Of 12 Volts Battery Charge With 75 Amp Hours Battery” was carried out and
submitted by
ENG/107150115 IGHOJOSEWE THOMPSON ONORIODE
________________________ _________________
Project Supervisor Date
MR.
USIDAME IMUZEZE
________________________ _________________
Program Co-ordinator Date
ENGR. AJAYI ADEBAYO
DEDICATION
We dedicate this project work to Almighty God for
his mercies, grace, strength, guidance, protection and loving kindness shown
unto us throughout our academic pursuit in the polytechnic.
ACKNOWLEDGEMENT
My special gratitude goes to Almighty God for
making it possible for us to successfully complete our programme.
I also sincerely appreciate the effort of my Head
of Department, Electrical Electronics Engineering: Engr. Abdulazeez Isah
Watson, my project supervisor Engr. Usidame Imuzeze, and all lecturers
Electrical Electronics Engineering whose guidance and suggestion made this
project a successful one.
My profound gratitude also goes to my Parents and all my family
members and those who have one way or the other help in my academic pursuit. May
the Almighty God richly bless them all.
ABSTRACT
In the world of today, there are different types of
battery chargers by different manufacturers but all ends up performing the same
function. A battery charger is electronic device used to induce energy into a
battery. It changes the A.C. voltage from the supply into a suitable D.C
voltage for the battery charging. The battery charger is usually made up of
step-down transformer which reduces the high A.C voltage to a low D.C voltage
and a bridge rectifier for converting the A.C. voltage to D.C voltage. The
rectified voltage then goes into a smoothening circuit for filtering away of
the ripple component of the rectified voltage and also for limiting the charger
current to prevent the flow of excessive charging current into the battery
under charge. The battery charger is centered around a LM350 integrated, 3 amp,
adjustable stabilizer IC. It’s a precision voltage source and it contains a
temperature sensor with a negative co-efficient. This particular circuit has
undergone different tests and found to be very advantageous. The advantages
includes (1) It is easy to understand and use
(2) It is up to both domestic and industrial standard. Other major
advantages include the fact that it can be used as a normal battery charger. It
is a perfect circuit to “Constant Charger” a 12-Volt Acid Battery and keeps it
in optimum charged condition.
TABLE OF CONTENT
TITLE PAGE. i
CERTIFICATION.. ii
DEDICATION.. iii
ACKNOWLEDGEMENT. iv
ABSTRACT. v
CHAPTER ONE. 1
1.0 INTRODUCTION.. 1
1.1 BACKGROUND OF
STUDY.. 1
1.2 VARIOUS SECTIONS
OF THE CHARGER.. 2
1.3 THE TRANSFORMER
UNIT. 2
1.4 THE ROLE OF THE
TRANSFORMER.. 3
1.5 THE RECTIFICATION
UNIT. 4
1.6 TYPES OF
RECTIFIERS. 4
1.7 THE FULL-WAVE
BRIDGE RECTIFIER.. 4
1.8 ADVANTAGES OF FULL
WAVE BRIDGE RECTIFIER.. 5
1.9 CHARACTERISTICS. 8
1.9 FORWARD CHARACTERISTICS. 9
1.9.2 REVERSE
CHARACTERISTICS. 9
1.10 BRIDGE RECTIFIER.. 10
1.11 RECTIFICATION
UNIT. 11
1.12 FILTER CIRCUIT
UNIT. 12
1.13 THE LOAD UNIT. 14
1.14 LEAD-ACID
ACCUMULATOR.. 14
CHAPTER TWO.. 16
2.0 THE STRUCTURE OF
THE BATTERY CHARGER.. 16
2.1 THE CASING.. 16
2.2 FABRICATION.. 16
2.3 THE COVER.. 17
2.4 THE BOTTOM OR CHASSIS. 18
CHAPTER THREE. 22
3.0 COMPONENTS OF THE
BATTERY CHARGER.. 22
3.1 THE CIRCUIT. 22
3.2 THE IC.. 23
3.3 RESISTOR.. 23
3.4 CAPACITOR.. 26
3.5 TRANSISTOR.. 27
3.6 THE
WIRING/MOUNTING OF THE COMPONENTS. 30
CHAPTER FOUR.. 32
4.0 TESTING AND RESULT. 32
4.1 THE FUSE. 32
4.2 CAPACITORS. 32
4.3 RESISTOR.. 32
4.4 TRANSFORMER.. 33
4.5 LED.. 33
4.6 THE IC.. 33
4.7 TRANSISTOR.. 33
4.8 THE BRIDGE RECTIFIER.. 34
4.9 THE CABLES. 34
4.10 TESTING CIRCUIT. 34
4.11 PROBLEMS
ENCOUNTERED.. 35
CHAPTER FIVE. 36
5.1 CONCLUSION.. 36
5.3 RECOMMENDATION.. 37
5.3 RECOMMENDATION.. 37
REFERENCES. 39
CHAPTER ONE
1.0 INTRODUCTION
1.1 BACKGROUND OF STUDY
This
project researches into the construction or making of a simple circuit or
device for the purpose of charging batteries.
These
batteries are secondary batteries which are called “Lead-Acid Batteries
Accumulators” and they require a great deal of care and maintenance, since they
are of great importance to the industrial world.
The
construction of the charger is such that it reduces the main supply voltage to
a considerable required voltage and then rectified. Then to eliminate any
ripples from the already rectified voltage, it is passed through a filter
circuit and finally to the battery to top of its voltage to the normal working
voltage of the battery.
The
battery charger is very useful to car owners since it helps to restore lost
energy to car batteries, which are Lead-Acid Batteries. It also finds its
usefulness in telecommunication and other industries where Uninterrupted Power
Supply (UPS) is desirable.
In
charging the battery, the positive of the charging supply should be connected
to the positive of the battery and it’s negative to the negative terminal of
the battery. This makes the induced voltage goes into the battery in the
opposite direction as at when is it in used. If no connected in the right
manner, it endangers the accumulator.
1.2 VARIOUS SECTIONS OF THE CHARGER
The
battery charger consists of or better still divided into four major parts.
These are;
Ø The
Transformer Unit.
Ø The
rectification Unit.
Ø The
filter Circuit Unit.
Ø The Load Unit.
These unit are
further discussed below.
1.3 THE TRANSFORMER UNIT
The Transformer
used is called a charger transformer. It is usually a step-down transformer. It
steps-down the supply voltage from about 240V (AC) to about 15V (A.C).
Basically,
the transformer consists of two windings whose coils have resistance. The
primary winding has a greater number of coils than the secondary winding and
not all the flux produced in either windings link each other. These windings
are enclosed in a core. The core has some reluctance and this causes hysteresis
and eddy current losses (core loss). These losses reduce the efficiency of the
transformer. So it is not 100% (one hundred) per cent efficient. However, the
transformer still work well since the percentage of efficiency is still
relatively high (about 85-97%) and as such, the losses experienced by the
transformer, pose little or no problem to the working of the charger.
1.4 THE ROLE OF THE TRANSFORMER
The
transformer helps to reduce the voltage to a level that the rectification unit
can rectify the A.C voltage to a corresponding D.C. voltage safely, without
burning out any of its components.
Note:
A switch (Toggle Switch) is placed before the transformer to close and open the
circuit depending on whether it is use or not.
1.5 THE RECTIFICATION UNIT
This unit has a rectifier which converts the
stepped down A.C. voltage to a D.C. equivalent voltage. This is done by
elimination of the sinusoidal waveform for the light A.C. signal. There are
various rectifier circuits arrangement.
1.6 TYPES OF RECTIFIERS
There
are basically two types of rectifiers, they are;
i.
Half wave Rectifier:- This involves the
use of a single diode.
ii.
Full Wave Rectifier:- The full wave
rectifier is further divided into two types;
v The
Reactive Centre-Tapped full wave rectifier which involves the use of two diodes
and a centre-tapped transformer.
v The
full wave bridge rectifier otherwise called the bridge rectifier. It involves
the use of four similar diodes arranged in a bridge circuit. For the purpose of
this project, we are using the full wave bridge rectifier system.
1.7 THE FULL-WAVE BRIDGE RECTIFIER
This
is the most commonly used rectifier in the electrical/electronic world for D.C.
power supply. It requires four diodes but the transformer is not centre-tapped
and it has a maximum voltage. The full wave bridge rectifier comes in 3 (three)
distinct physical forms, namely;
v Four
(4) discrete diode.
v One
device inside a four terminal case.
v As
part of an array of diodes in an I.C.
v The
full bridge rectifier was chosen for this project work because of some
advantages it has over the others.
1.8 ADVANTAGES OF FULL WAVE BRIDGE RECTIFIER
After
the advent of low-cost, highly reliable, small size, semi-conductor diodes. The
bridge circuits are used more often than before, because a much smaller
transformer is required for the same output.
This is due to the fact that it utilizes the secondary winding of the
transformer continuously unlike the two-diode rectifier which uses the two
halves of the secondary winding alternately and therefore requires a larger transformer.
The
advantages of the bridge rectifier are given below;
i.
No Centre-tap is required on the
transformer.
ii.
Much smaller transformer are required.
iii.
It is suitable for both high and low
voltage applications.
iv.
It has less peak inverse voltage (PIV)
rating per diode.
The
only disadvantage associated with this type of rectifier is that it requires
twice as many diodes used for the centre-tapped transformer version. But this
has been taken care of by the introduction I.C technology where the four diodes
could be integrated into one suitable chip.
Note:
I.C. means Integrated Circuit.
We
are going to further discuss the major components of the rectifier, which is a
diode.
THE DIODE:- As earlier stated, the
diode is the major component of the bridge rectifier. Four of the diodes are
arranged in a bridge circuit to do the rectification.
The
diode is a two terminal semiconductor device consisting of a PN junction formed
from their Germanium (Ge) or silicon (Si) crystals. Its circuit symbols are
shown below:
P-N Junction Diode
Fig. 1.2 Diode Symbol
The
P and N type regions are referred to as anode and cathode respectively. The
arrowhead lead in fig (ii) above indicates the conventional direction of
current flow when forward biased.
There
are two major types of diodes namely:
i.
Junction Diode.
ii.
Light emitting diode (LED).
Another
important type of diode is the Zener diode. The junction diode is used in
circuits for various purposes eg. In a bridge circuit for rectifications while
the LED is used in circuit mostly to indicate the presence of power and also
for signaling. The Zener diode resembles the junction diode appears to be
smaller than the junction diode. They are also different in circuit symbols.
The Zener diode is mostly used in circuits as voltage stabilizers.
Fig 1.3 Diagram of PN Junction Diode
Fig. 1.4 Diagram of a LED
Fig. 1.5 Diagram of a Zener Diode.
The
P-N junction diode is a one-way device offering very low resistance when
forward biased and behaving almost as an insulator when reversed biased.
1.9 CHARACTERISTICS
The
characteristics of the diode is shown in fig. 1.6.
Current µA, mA
Fig. 1.6 Diode Characteristics
Graph.
1.9 FORWARD CHARACTERISTICS
When
the diode is forward biased and the applied voltage is increased from zero,
hardly any current flows at first. This is caused by the external voltage being
opposed by the internal barrier voltage VB whose value is 0.70V for
Silicon and 0.30V for Germanium.
As
soon as VB is neutralized or reached, current begins to flow through
and the current increases rapidly with an increase in the applied voltage. It
is observed that as little observed that as little as a voltage of 1.00V
produces a forward current of about 50mA. A burnout is likely to occur if the
forward voltage is increased beyond a certain safe unit.
1.9.2 REVERSE CHARACTERISTICS
When
the diode is reverse biased, majority carriers are blocked and only a small
current (due to minority carriers) flow through the diode. As the reverse
voltage is increased from zero, the reverse current varies quickly, reaches its
maximum or saturation value IO, which is also leakage current. It is
of the order of nano amperes (nA) for Silicon and microamperes (µA) for germanium.
The
value of IO is independent of the applied voltage, but depends on
the following.
a) Temperature
b) Degree
of doping and
c) Physical
size of the junction.
In
the field of engineering (Electrical/Electronics), the properties of diode are
utilized for rectification purpose. The diodes are mostly of small sizes with
different voltages and power rating as for the battery charger. Diodes are
arranged as rectifiers in different forms.
i)
Half wave rectifier – Single diode used.
ii)
Centre-Tapped full wave rectifier – Two
diodes used.
iii)
Full wave bridge rectifier – four diodes
used.
1.10 BRIDGE RECTIFIER
During
the positive half cycle of the input signal end A of the transformer secondary
becomes positive while end B becomes negative. This makes diode D2
& D4 forward biased, while D1 & D3 are
revered biased. Hence, diode D2 & D4 conduct the
positive half cycle alone.
During
the negative half cycle of the input A.C. signal, end B becomes positive and
End A negative. This makes diode D2 & D4 reverse
biased and D1 & D3 conducts the negative half circle.
See fig 1.7.
Fig
1.7 Bridge Rectifier Circuit.
The
input A.C. voltage and the corresponding output D.C. voltage which was due to
the rectifier action is as shown in fig 1.8.
Fig.
1.8 Rectifier Input and Output Wave form.
1.11 RECTIFICATION UNIT
Batteries
require D.C Voltage for their charging condition. Since the readily available
voltage and current sources are in the A.C form, it has to be converted to D.C
which is used for charging the battery. The work or role of the rectifier
(Rectification Unit) is to convert the A.C voltage signal to its equivalent D.C
voltage signal for the battery charging.
In
the rectification process (conversion of A.C. to D.C.), there is a term called
ripple factor. This is defined as the ratio of the r.m.s value of the A.C.
components to the value of the D.C component is also considered due to the fact
that the rectified D.C. voltage is a pulsating D.C.
1.12 FILTER CIRCUIT UNIT
The
main function of the filter circuit unit is to minimize the ripple content in
the rectifier output. As earlier stated, the output of the rectifier is a
pulsating D.C. voltage. It has a D.C. value and some A.C. components called
ripples. This type of output/voltage is not useful for driving gadgets like batteries.
In fact, these gadgets require a very state D.C. output that approaches the
smoothness of a battery’s output.
Fig. 1.9 Filter Circuit
Fig. 1.10 Filter Output
This
circuit smoothing out the pulsating output from the rectifier into a very
steady D.C. level. It is called a filter circuit because it filters out the
ripples or smoothing the pulsation of the input voltage.
This
circuit comprises of:
i)
Capacitor.
ii)
Resistance and Potentiometer.
iii)
Transistors.
iv)
An I.C.
v)
A light emitting diode (LED).
All
of the above work together to smoothen the voltage from the rectifier for the
purpose of charging the battery.
1.13 THE LOAD UNIT
The
load here refers to the battery which is being charged. A battery can either be
a primary or secondary type depending on whether it can be recharged or not.
Those that cannot be recharged are called secondary batteries or accumulator.
Examples of primary batteries are Layer batteries, Le Clanche batteries and
others. The secondary batteries are of two types:
·
Lead-Acid Battery of Accumulator.
·
Nickel- Cadmiun Alkaline Battery or
Accumulator.
1.14 LEAD-ACID ACCUMULATOR
Lead-Acid
battery is the most widely used battery in the industrial world. They are used
for ignition and lighting on motor cars and also as source of spare power on
ships. Their main advantage is that they have low internal current resistance
and hence can give large current with a very drop in terminal potential
difference.
The
Lead-Acid battery is made up of the following;
·
The container.
·
The plate(s)
·
The separator.
·
The electrolyte.
Fig. 1.11 Lead Acid Accumulator
The
current from charger usually run into the battery through a series connection.
CHAPTER TWO
2.0 THE STRUCTURE OF THE BATTERY CHARGER
2.1 THE CASING
The casing of the
battery was made of Aluminum and it was well earthed. This was used to enclose
the components of the charger for easy carriage and to avoid the exposure of
the components to hazards and the earthing was done to prevent or reduce the
risk involved when there is leakage current. The casing is easy to carry and
portable.
The casing is
fabricated in such a way that it was divided into two parts;
v The
cover or top.
v The
bottom or chassis.
These two were joined
together by the use of screws.
The components, both
internal and external were all positioned on the chassis while the cover was
used to secure them inside.
2.2 FABRICATION
As earlier stated, the
casing is divided into the cover or top and the bottom or chassis. Their
description and developments are separately dealt with below;
2.3 THE COVER
The development pattern and physical
nature of the cover/top is as shown in fig. 2.1.
DIMENSIONING
Height
of cover/top ----- 152mm.
Length
of cover/top ------ 220mm.
Width of cover/top
------- 124mm.
The development of the casing is explained below;
Ø Diagram
A is the plan.
Ø Diagram
B is the top view.
Ø Diagram
C is the view when the cover is flattened out.
From the diagram, A and
C are the two sides of the cover while B is the top of the cover. When A and C
were folded towards B, the shape of the cover was achieved.
The holes for the
nut/screws were then located on it and it was perforated on the two sides to
allow ventilation in other to prevent over heating of the components.
2.4 THE BOTTOM OR CHASSIS
The development and
physical nature of the chassis are shown below. Its dimensions are the same with
the cover.
Fig.
2.4 Parts of the Bottom Cover
Like the cover, the
development of the chassis/bottom has;
Diagram A – The plan.
Diagram B – The top
view or bottom view.
Diagram C – The view
when it is flattened.
Also, in diagram C, A
& C are the two sides while B was the bottom. When A and C are folded
towards B, the shape of the chassis was achieved.
Although
the ideal dimension are given in the development, in practical case the
dimension are increased by 10mm on each of the four corners, so that when the
additional lengths were bent, they provided the space for the screw to be bored
in.
The
holes for the screws were located and also for the external components (i.e
those components that are seen outside) such as, the meter, the switch, the
supply cable, the output terminals etc the position of all these were located
and about four holes were bored on the bottom to provide space to screw the
vero-board on.
After
all the above listed activities were carried out, the casing was then painted
to insulate it in order to reduce the risk of electric shock, if any is
possible, then handling the charger.
A
rubber handle was attached to the top of the cover for easy handling and four
rubber cushions were fixed to the bottom of the chassis to serve as stands to
the chargers. These stands help to separate the charger from the ground and
thus reduce the possibility of rust which may result from moisture that
accumulates at the bottom of such a material as due to heat effect when the
material is left in contact with the floor for some times. By the inclusion of
the standings, there is enough ventilation and so the heat minimized if not eliminated.
Due
to the fact that the dimensions were increased, the shape of the material used
for the chassis is given fig. 2.5.
Fig.
2.5 Diagram of the Chassis
CHAPTER THREE
3.0 COMPONENTS OF THE BATTERY CHARGER
3.1 THE CIRCUIT
The
circuit of the battery charger consists of the following components;
COMPONENTS
|
QUANTITY
|
LM317 IC
|
1
|
120Ω Resistor
|
1
|
82Ω Resistor
|
2
|
10kΩ Resistor
|
3
|
33kΩ Resistor
|
4
|
22kΩ Resistor
|
5
|
470Ω Resistor
|
6
|
2k Potentiometer
|
1
|
100µf/50v Capacitor
|
1
|
10µf/50v Capacitor
|
2
|
BD 140 Transistor
|
1
|
BC 547 Transistor
|
2
|
These
components will now be treated separately.
3.2 THE IC
The
IC LM 317 is an integrated 3-amp, adjustable stabilizer IC. It is a 3-terminal
regulator that has current and voltage limit, safe area and thermal shut down
protection.
The
pin 1 is the adjustable terminal, pin 2, the output terminal and pin 3, the
input terminal. Its physical nature is shown in fig. 2.3.
Fig. 2.3 IC Symbol
The
adjust pin keeps the voltage drop between the input and output pins at a constant
value of 1.25v so as there is a constant flow of current through R1.
3.3 RESISTOR
A
resistor is an electrical components especially designed and having the
property of resistant known as resistance. It is used to control the amount of
current flows in a particular part of a circuit. Resistors are of two (2)
types; fixed and variable resistors.
Fixed
resistors have their ohmic value set by the manufacturer and cannot be easily
changed. Examples of these are the carbon composition, film and wire wound
resistor.
The most commonly used is the carbon
composition resistor, which is made from a mixture of carbon black
(non-conductor), which are pressed and molded into rods by heating.
Variable
resistor are designed in a way that their resistance value can easily be changed with a manual or an automatic
adjustment.
There
are basically two types which are potentiometer and rheostat. Their schematic
symbols are shown fig 3.4.
Fig. 2.4
In
the circuit, a potentiometer is used.
For the carbon, their
values are indicated by use of colour codes. eg
Fig 2.5 Diagram Showing Color Codes
The
tolerance gives a range of values that can be used in place of the given value.
That is for a resistor marked 470
5%, any resistor that
falls in the range of 446.5Ω to 493.5Ω can be used in place of it.
The
colour coding are given in table 1.
Table 1
Resistance
value for fist three band.
|
0
|
Black
|
1
|
Brown
|
2
|
Red
|
3
|
Orange
|
4
|
Yellow
|
5
|
Green
|
6
|
Blue
|
7
|
Violet
|
8
|
Grey
|
9
|
White
|
0.01
|
Silver
|
0.1
|
Gold
|
Tolerance value for fourth band.
|
2%
|
Red
|
5%
|
Gold
|
10
|
Silver
|
20%
|
No Band
|
The
value of resistor is ohms (Ω).
3.4 CAPACITOR
A
capacitor consist of two metal surface separated by a dielectric. It is
arranged in such a way that it has the ability of storing electricity. This is
termed capacitance. It is the constant of proportionality between charge and
potential difference (P.D.) of a system. The unit of capacitances is called
farad (F).
There
are different types of capacitor; air, paper, mica, ceramic and electrolytic
capacitor. In this project work, the electrolytic capacitor is used.
The
electrolytic capacitor is the most commonly used capacitor. It consists of two
Aluminum foils, one with an oxide foil and the other without any foil. They are
separated with a paper saturated with suitable electrolyte. The foil with the
oxide is the positive plate, the oxide layer is dielectric, the paper is the
electrolytic and the other aluminum foil, is the negative plate.
The
electrolyte is used due to the fact that it is suitable for comparatively high
capacitance value ranging from a few micro-farads to several thousands of
micro-farads.
The circuit symbol of a capacitor is shown in fig.3.6
Fig 3.6 Circuit and Physical
Symbols.
3.5 TRANSISTOR
A
transistor is a semi conductor amplifier of current. It has three
semi-conductor layers. It is of two types; the NPN and the PNP. The NPN
transistor is a transistor that has two outer N-semiconductors with an
extremely thin P-semiconductor sandwiched between them. The diagrams of a
transistor are shown in fig 3.7.
Fig 3.7 Circuit Symbol and Physical
Structure of transistor
The
alphabets e,b,c refers to emitter, base, collector respectively.
The
major function of a transistor is amplification. It can also be use as a
switch.
Fig 3.8 Circuit Diagram.
3.6 THE WIRING/MOUNTING OF THE COMPONENTS
The wiring
diagram of the circuit of battery charger is shown below in fig 3.9.
Fig 3.9 The Wiring Diagram Of The
Circuit
The
components were fixed to a Vero board through soldering.
The
soldering was done using;
Ø A
soldering iron off 220V, 60 watt.
Ø Soldering lead
(flux solder).
After
the mounting and wiring of the circuit, the Vero board was placed inside the
chassis of the casing and the outer components such as the meters, the supply cable,
the leads, the fuse and the output terminals were all fixed at their
appropriate positions. The transformer was then screwed to the chassis.
The cover of the
casing was held down by means of screws. The battery charger was thus
completed.
The completed
battery charger is as shown in fig. 3.10
Fig. 3.10 complete battery charger.
CHAPTER FOUR
4.0 TESTING AND RESULT
Before
the components were put together, they were all tested for their effectiveness.
4.1 THE FUSE
The
fuse was tested with the use of multi-meter. The knob of the digital
multi-meter was set to continuity so as to carry out a continuity test.
4.2 CAPACITORS
The
multi-meter was set to ohm range. The reading of the multi-meter was at maximum
value and gradually return to zero indicated that the capacitors are good.
4.3 RESISTOR
The
testing of the resistor requires setting the multi-meter to ohm range. The
measured value is compared to the colour code value. Their equality indicated
that the resistors are good.
4.4 TRANSFORMER
The
transformer was tested for both continuity and short circuit tests. For the
short circuit test, the multi-meter was set to the buzzer and the sounding of
the buzzer indicated that the there was no short circuit. The multi-meter was
also set to the buzzer for the continuity test and the sounding of the buzzer
indicates that the transformer coils were continuous. Therefore, the
transformer was found to be good.
4.5 LED
The
LEDs were tested with the multi-meter and found to be okay.
4.6 THE IC
The
IC was tested with the multi-meter. The multi-meter was set to the point and
the pulse of the IC was tested. At the end, the IC was found to be good.
4.7 TRANSISTOR
The
transistors were first tested to get the positions of the base, emitter &
collector and also to ascertain that the transistor were okay. At the end, it
was found that the transistor were okay.
4.8 THE BRIDGE RECTIFIER
On
one pin of the rectifier there was a positive sign. The red probe of the
multi-meter was put at the positive point, while the black probe of the
multi-meter was put at the pin with the negative sign. There were positive
readings to show that it is in forward bias but when the probe was reversed,
there were no readings. This indicates that the rectifier was ok.
4.9 THE CABLES
The
multi-meter knob was set to continuity to enable a continuity test. The
sounding of the buzzer indicate that the cables were all good.
4.10 TESTING CIRCUIT
After the construction, the circuit was also
tested. It was observed that the output voltage varied between 12.5v and 14.5v,
D.C. it was also observed that the output voltage has a negative temperature
co-efficient due to the fact that Q1 contains a temperature
co-efficient of 2mVoC. also the casing of the charger was tested to
check the effectiveness of the earthing and the earthing was found to be
effective as there was no electric shock.
4.11 PROBLEMS ENCOUNTERED
During
the entire process involved in the construction of this battery charger, some
problems were encountered and these are noted below;
Ø Scarcity
of required values of some of the components. This problem was however,
rectified by substituting for the components using the equivalents.
Ø Unavailability
of current textbooks relating to the required project work. This problem was
tackled by the use of the internet, which consumed a lot of money.
Ø Power
supply failure was the major problem encountered during the development of the
charger.
CHAPTER FIVE
Conclusion,
innovation, recommendation and problem encountered
5.1 CONCLUSION
The
battery charger was constructed in the electrical workshop. The charger was
able to restore energy back in the chemical form to the cell plates of a
led-acid accumulator (commonly called battery).
The
performance of the battery charger was satisfactory, therefore we can say a
step towards technological advancement is done.
The
test carried out before the construction provided useful information which
helped to secure that the charger was technologically sound. A lot of easthetic
values like heat sinking, earthing and ventilation, were taken into
consideration to establish proper and safe charging condition.
The
charger circuit could be more complex but was kept this way due to the fact
that more complex circuits contains more components hence higher costs. And
also this chapter helps one to concentrate on the general principle of
power/product engineering.
Hence
the battery charger is a precision voltage type.
5.3 RECOMMENDATION
The
school management should be the availability of good and current textbooks to
aid students in projects like this.
Ø The
department should endeavour to ensure that
components of different values are made available to students at a
considerable amount to check the risk involved in travelling or transportation
to get the required components.
Ø The
department should endeavour to ensure the availability of constant power supply
in the workshops and also improve the power factor.
5.3 RECOMMENDATION
Ø This
project is recommended for schools and academic laboratories and also for
students that want embark on this type of project work.
Ø The
charger is recommended for car owners recharging their batteries.
Ø For
funding, the charger can be installed in the electrical workshop for commercial
charging.
Ø It
is also recommended that the government should render assistance to individuals
or groups of people who want to embark on this type of project.
Finally,
in conclusion, the major problem(s) involved with this charger is the scarcity
of components. This is because none of the components are locally made, so they
can be out of market at any time. Users are therefore advised to take good care
of this charger so that it will serve them for general years. They are also
advised, not to use the charger Gel type batteries, since it draws much
current.
Gainfully,
users will find it cheaper to use this locally made charger than a foreign made
one.
REFERENCES
M.
Nelkon, (1977), Principle of Physics, 7th Edition, Hart-Davis
Educational.
Hughes
E., (1987) Electrical Technology, Longman Scientific Publication, London Group,
London.
Theraja
B. L. and Theraja A. K., (2002), A textbook of Electrical Technology, S. Chand
& Co. Ltd, New Delhi.
Odunsi
J. A., Electrical Maintenance and Repairs, Ayenbros Enterprises, Lagos.
www.uogelph.ca/~antoon/circs.html via Google search.
www.wikipedia.org
via Google search.
