DESIGN AND CONSTRUCTION OF AUTO TURN-OFF BATTERY CHARGER
This project is titled design and construction of an auto turn off battery charger. Automatic battery charger presented here is an acid battery charger that is designed to charge cell phone.
An Auto turn off battery charger proceeds to charge battery automatically. When the battery is charged it will shut off
The objective of this project is to design and construct an electronic device that will supply electrical energy (charges) to a cell phone battery, in a process to restore the battery’s used up energy.
An auto turn off charger is an electrical device employed in charging cell phone batteries known as “lithium-ion battery”. This charger automatically shut off the charging process when battery attains full charge. This prevents the deep charge of the battery. If the battery voltage is below the set value, then circuit automatically charges the battery.
The charger is made up of various electrical and electronics component which for the purpose of clanty are group into your basic unit they are:
The power supply units
The smoothing circuits
The regulating unit and
Regulated D.C charging units
An Auto turn off battery charger is a good option for people who don’t like having to mess with the battery charging process too much. Simply hook our battery up to an Auto turn off battery charger and we will find that it proceeds to charge our cell phone battery automatically. When the battery is charged it will shut off. Hooking a battery up to an Auto turn off battery charger is really easy too. Simply hook the alligator clips up to the battery posts and leave the Auto turn off battery charger plugged in. A battery will never get overcharged with an Auto turn off battery charger. Many people choose an Auto turn off battery charger over a manual battery charger can fry our batteries by not shutting off when the battery is charger up. This can cause a lot of headaches and prevent us from getting the life expectancy out of the batteries we purchase.
1.2 OBJECTIVES OF THE PROJECT
The objective of this work is constructing a charger that will automatically shut off the charger when battery attains full charge. This prevents the deep charge of the battery. If the battery voltage is below the set value, then circuit automatically on the device.
1.3 SIGNIFICANCE OF THE PROJECT
Advantages A manual battery charger can fry our batteries by not shutting off When the battery is charged up where as this battery charger will never get overcharged with an auto turn off battery charger. This charger provides the full life expectancy out of the batteries we purchase. Easy to use. Simple circuit. Components are easily available and low cost. User friendly product.
1.4 APPLICATIONS OF THE PROJECT
Applications This battery charger is intended to charger any battery ranging from 0 to 15V. Some of the applications are Rechargeable Cells Motorcycle Batteries Car Batteries Mobile phone charger
1.5 LIMITATION OF THE PROJECT
Subjecting a discharged cell to a current in the direction which tends to discharge it further to the point the positive and negative terminals switch polarity causes a condition called cell reversal. Generally, pushing current through a discharged cell in this way causes undesirable and irreversible chemical reactions to occur, resulting in permanent damage to the cell. Cell reversal can occur under a number of circumstances, the two most common being:
- When a battery or cell is connected to a charging circuit the wrong way around.
- When a battery made of several cells connected in series is deeply discharged.
In the latter case, the problem occurs due to the different cells in a battery having slightly different capacities. When one cell reaches discharge level ahead of the rest, the remaining cells will force the current through the discharged cell.
Many battery-operated devices have a low-voltage cutoff that prevents deep discharges from occurring that might cause cell reversal.
Cell reversal can occur to a weakly charged cell even before it is fully discharged. If the battery drain current is high enough, the cell’s internal resistance can create a resistive voltage drop that is greater than the cell’s forward emf. This results in the reversal of the cell’s polarity while the current is flowing. The higher the required discharge rate of a battery, the better matched the cells should be, both in the type of cell and state of charge, in order to reduce the chances of cell reversal.
In some situations, such as when correcting Ni-Cad batteries that have been previously overcharged, it may be desirable to fully discharge a battery. To avoid damage from the cell reversal effect, it is necessary to access each cell separately: each cell is individually discharged by connecting a load clip across the terminals of each cell, thereby avoiding cell reversal.
1.6 PROJECT WORK ORGANISATION
The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:
Chapter one of this work is on the introduction to automatic turn-off battery charger. In this chapter, the background, significance, objective limitation and problem of an automatic turn-off battery charger were discussed.
Chapter two is on literature review of an automatic turn-off battery charger. In this chapter, all the literature pertaining to this work was reviewed.
Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.
Chapter four is on testing analysis. All testing that result accurate functionality was analyzed.
Chapter five is on conclusion, recommendation and references.