-
Design And Construction Of 12v Battery Charger
CHAPTER ONE -- [Total Page(s) 3]
Page 1 of 3
-
-
-
CHAPTER ONE
INTRODUCTION
1.1 Background of Study
Few modern
electrical appliances receive their power directly from the Utilitygrid
like National Electricity Power Authority (NEPA) or Power Holding
Company of Nigeria (PHCN), while a growing number of everyday electronic
and electrical devices require electrical power from batteries in order
to achieve greater mobility and convenience. Rechargeable batteries
store electricity from the utility grid for later use and can be
conveniently recharged when their energy has been drained. According to
Woodbank Communications Ltd in their 2005 battery chargers and charging
methods review inhttp://www.mpoweruk.com, battery charging involves
three key functions: getting the charger into the battery (charging),
optimizing the charging rate (stabilizing) and knowing when to stop
(terminating). Appliances that use rechargeable batteries include
everythingfrom low-power mobile cell phones to high-power industrial
fork lifts. The sales volume of suchproducts has increased dramatically
in the past decade. Hundreds of millions of theseproducts are sold
annually to businesses and consumers, with close to a billion in U.S and
Nigeria.
While designers of battery chargers often maximize the
energy efficiency of their devices to ensure long operation times
between charging. They often ignore how much energy is consumed in the
process of converting ac electricity from the utility grid into dc
electricity stored in the battery. In this project design, significant
energy savings are possible by reducing the conversion losses associated
with charging batteries in battery-powered products. We could save a
lot of electric power using new electronic technology in our charging
system and then highlight several design strategies for improving the
efficiency of other chargers. We introduced a smart or intelligent
battery charger that does not only recharge batteries but conserves AC
electrical energy and as well save the battery life. Most battery
chargers require human attention say Chu, Kim-Chiu the writer
‘development of intelligent battery charge’ (1989), from the University
of Hong Kong, but in this project, an automatic battery monitor is used
to reduce human attention to about 85 per cent to eliminate overcharging
of batteries.
1.2 What is A Battery Charger?
A battery charger is
a system that draws energy from the grid, store it in a battery, and
release it to power a device is called a battery charger system.
A
system designer in ADACC(Engr. A.A Ndubuisi) in his 1999article
describes a battery charger is an electrical and electronic device that
is used to put energy into a secondary cell or rechargeablebattery by
forcing an electric current through it.The charging protocol of a
battery charger depends on the size and type of the battery being
charged. Some battery types have high tolerance for overcharging and can
be recharged by connection to a constant voltage source or a constant
current source; simple chargers of this type require manual
disconnection at the end of the charge cycle, or may have a timer to cut
off charging current at a fixed time. Other battery types cannot
withstand long high-rate over-charging; the charger may have temperature
or voltage sensing circuits and a microprocessor controller to adjust
the charging current, and cut off at the end of charge. A trickle
charger provides a relatively small amount of current, only enough to
counteract self-discharge of a battery that is idle for a long time.
Slow battery chargers may take several hours to complete a charge;
high-rate chargers may restore most capacity within minutes or less than
an hour, but generally require monitoring of the battery to protect it
from overcharge.
Christine T. Bryant, (1990) say not all chargers can
recharge alkaline batteries. It makes sense to use alkaline batteries
while powering electronic systems even though they are difficult to
recharge but they do not have a self-discharge. This is because alkaline
batteries have long shelf lives and do not suffer the 'memory effects'
of Nickel-cadmium batteries. The term 'memory effects' refers to the
batteries becoming weaker with continued use, particularly when the
batteries have seen light use and do not respond well to further
charging. The problem stems from low battery currents which flow from
only a small part of the active anode area of the battery. If higher
current had been drawn or if the battery had been completely discharged,
the whole active area of the anode would have been involved. The unused
area essentially 'films over' and acts as a barrier to current flow.
Further charging does not restore the active area. This is a chemical
change causing the electrodes to degenerate in Nickel-metal hydride and
Nickel-cadmium batteries. It is reversible by charging and discharging
several times. Batteries that are not recharged before use will not
supply the full amount of stored energy. None of the above happens with
common alkaline batteries. The rate of self discharge in Nickel-cadmium
is about 2% per week, in Nickel-metal hydride it is about 3% per week.
CHAPTER ONE -- [Total Page(s) 3]
Page 1 of 3
-
-
ABSRACT - [ Total Page(s): 1 ]This project presents the design and construction of a battery charger. A battery charger is an electrical/electronic device used to put energy into a secondary cell or rechargeable battery by forcing an electric current through it. The system consists of a step down transformer, an AC to DC converter and a DC voltage regulator. The circuits are designed using copper wire, rectifier diodes, electrolytic capacitors, resistors with other passive and active component of electronics. A battery charg ... Continue reading---
