Battery is the device that stores electrical energy. Major categories are primary batteries and secondary batteries. So primary batteries become empty cannot charge while secondary batteries because once used and become empty charge again. So battery is among one of power sources that has become one of important resources that man can cannot make up life in its absences.
PROJECT OBJECTIVES.
Main objective.
To reduce damage of the battery due to overcharging of batteries by using charger controller and indicator so as to maintain life span of the battery and its.
After the successful completion and implementation of this project following needs;
Maintaining life span of the battery and its performance and protect them from over charging.
Charger will be able to protect the battery from over charging.
So an indicator is able to determine level of the battery exist before or after charging for a particular period of time.
EXISTING SYSTEM.
The existing system consists of the transformer, rectifier, filter, regulator and a battery.
LIMITATION OF THE EXISTING SYSTEM.
It cannot protect the battery from overcharging, the existing system consists of the transformer, rectification circuit that changes the secondary voltage of the transformer into DC, so filter which is to smooth DC output and regulator which supply a stable voltage ready to charge the battery.
It does not contain charger controller for switching on/off automatically.
ADVANTAGES OF PROPOSED SYSTEM
It produces regulated charging current which reduce damage and maintain the life span of the battery.
It protect the battery from overcharging due to voltage
Knowing when to stop(monitoring section)
DATA ANALYSIS.
INPUT SECTION.
Step down transformer evaluation.
DC voltage needed is 12V.
So the mains supply from TANESCO (220-240) V.
Average mean= (220+240)/2
=230V
Stepdown transformer reduce 230V AC voltage to the required 12V AC voltage.
Primary voltage(Vp)=230V,
Secondary voltage(Vs)=12V.
Turn ratio(Np/Ns) =Vp/Vs.
Turn ratio= (230/12) V =19.1667.
⸫Turn ratio=1:19
Hence, transformer is 1:20.
INDICATION SECTION.
Here, BC547 transistor used as a switch.
From data sheet;
Ic≤200mA
Ib≥1µF
Β=120-150
Vc≤24V
So VCC=IcRc
Rc=Vcc/Ic
BUT Rc=12V/200mA
Rc=60Ω
Rc=60Ω but standard value of Rc=62Ω
But Ic=βIb
Ib can found by equation;
Ib=Ic/β
Ib=20mA/120
Ib=1.66mA
Vb=IbRb
Rb=Vb/Ib
Rb=12V/1.66Ma
Rb=7228.9Ω
Rb=7.2KΩ
⸫ Rb1=Rb2=7.2KΩ
CONTROL SECTION.
Relay of 12V from data sheet and Diode of 1N4007.
Green LED of2.5V and Red LED of 2.5V.
The relay coil operates in flowing of voltage current to the TRANSISTOR Q3- BC 547 used as switch in controlling charging party. Also, when the battery is full charge the coil of relay connects to Transistor circuit and makes the supply circuit open. Hence protects the battery from over-charging.
Diode of 1N4007 parallel to the relay protect the relay from damage by high Voltages generated by the back e.m.f.
SWITCHING AND CHARGING SYSTEM
From the designing of the project transistor Q1 BC547 will work only when the battery is full charge i.e. it turns ON cutting off the supply that charges the battery.
Monitoring of the battery, when the battery is full charge. During charging of the battery, the Zener diode network is set off depending on the amount of battery voltage charge. For 12Vand15V lead acid battery the output voltage from the charged battery network is set 12.5 exceeding the Zener voltage.
The output 12.5V of the charged voltage acts as the input to TRANSISTOR_2 BC 547 makes it to conduct AS A SWITCH. When in saturation the LED below Zener diode emits green color indicating the battery is full charged. At the same incidence the relay coil connected with Transistor_2 change over to switch the LED and the BC547 transistor 2 ON while disconnecting the supply source to the lead acid battery preventing the overcharging and damage of the battery. The relay coil connects to the supply again when the lead acid battery is low or medium voltage level compared to Zener voltage of 12V.
CONCLUSION
The aim of the project was to design a battery charger for reducing damage of batteries due over- charging in the charging system.
The objectives have been achieved; The system has been undertaken successfully In order to meet Main objective of the project such as general introduction, problem statement, literature review, data collection, data analysis had been covered, and designing the circuit, Building and testing the prototype, discussion results and Report writing were all covered.
The project design is successfully to ensure provision of quality battery charger to charge batteries of 12V.The project is to be beneficial to users since the Analysis and Prototype results were exactly the same for charging that provide constant voltage; monitoring while controlling voltage of the level of battery voltage when full charged hence prevents damage of batteries due to overcharging.
RECOMMENDATION.
We should modify the proposed system by using other power sources of energy like solar energy to be used not only in urban areas but also in Rural areas, working even if there is no supply from mains. In demonstration any battery of 6V-12V should be used for minimizing more costs.