Lead Acid Battery Performance Analysis

Implementation and Performance Analysis of a Fast Charger for Lead Acid Batteries

Md Al Mamun

Institute of Energy Technology

Chittagong University of Engineering and Technology chittagong, Bangladesh [e-mail] Muhtasim Aziz Muneem Department of Biomedical Physics and Technology

University of Dhaka

Dhaka, Bangladesh [e-mail]

Syeda Nusrat Ferdous Department of Electrical& Electronic Engineering American international university Bangladesh

Dhaka,Bangladesh [e-mail]

Abstract— This paper represents a method for developing a fast charging feature of batteries that are used in backup power supplies. As power outage problem has become so severe in our country, load shedding has also become

Emergency power supplies with instant back-up capabilities are being used to reduce this problem. In order to tackle such problem a battery with higher power storage capability is needed to provide backup power. Fast charging of battery used in backup power supply is a better option for minimizing this problem. Lead acid battery is used in this type of cases as high amount of energy can be stored in it and can be preserved for a long time. A battery charger is used to supply energy into a cell or battery by forcing electric current through it. Two different tasks can be accomplished by Lead Acid battery chargers. Restoring the capacity often as quickly as possible is one of the tasks and maintaining the capacity by compensating for self-discharge is another work that a Lead Acid battery can perform. Lead acid battery dissipates very little energy, so that work can be done with high efficiency. On the basis of cost-per-watt this battery is inexpensive, even no special ventilation or no water maintenance is required for acid fume. Charging a lead acid battery is simple, but appropriate voltage must be observed while charging.

LM338K has been used as a voltage regulator to provide constant charging voltage to the battery. It is also used to provide high charging

If none, delete this text box. Output of the step down transformer is of low voltage and high current. A bridge rectifier has been to convert the AC output to 24V DC but not constant DC. In order to handle the high output current, two different approaches has been tested. They are-

• Construction of a bridge rectifier using 1N5406 Diode

• Using 50V 10A KBPC5010 bridge rectifier. Fig.2: Bridge rectifier using 1N5406 diodes

C. Smoothing capacitor A smoothing capacitor has been used to smooth or even out fluctuations in a signal. The most common and used application for smoothing capacitors is after a power supply voltage or a rectifier. In this case, the smoothing capacitor of 4700µF 50V has been used after the bridge rectifier. It also worked as a Bypass capacitor for the LM338K voltage regulator.

D. Voltage Regulator Voltage Regulator is a vital part of this circuit. It is one of the main components responsible for fast charging. For this work Voltage Regulator LM338K has been used. Notable features of LM338K are:

• 7A Maximum output current

• Adjustable output 1.2V to 37V

• Current Limit Constant with Temperature

• Output is Short-Circuit