Design and implementation of a microcontroller-based adjustable voltage automatic battery charger

Battery chargers come in different shapes, sizes and capacities, but it is difficult (if not rare) to find one charger unit that regulates overcharge and can charge different battery voltages. This work uses the basic electrical principles and ICs, to design a user friendly charger circuit that manually adjusts the voltage depending on the voltage of the battery, (6volts, 9volts and 12volts was considered because it is generally available). The circuit charges in three modes namely: Burst charging, trickle charging and pulse charging. It also incorporates a Liquid Crystal Display (LCD) to display the voltage that is being charged. The circuit also uses a Pulse Width Modulator (PWM) in order to control the duty cycle and voltage. The circuit also has an overcharge and over discharge protection. This remarkable charger saves the user time and resources needed to purchase three different chargers for three batteries, with different voltages. From the result obtained the built battery charger was able to charge 6volts (10Ah), 9volts (1200mAh) and 12volts (10Ah) battery to 100% state of charge. The charging time for the 6volts battery was 2hours 24 minutes, 2 hours 36 minutes for the 9volts battery and 2 hours 30 minutes for the 12volts battery.Keywords: Burst Charge, Depth-Of-Discharge DOD, Pulse Charge, State-Of-Charge SOC, Trickle charge, Duty Cycle