Lead Acid Batteriesare one of the oldest rechargeable batteries available today. Due to their low cost (for the capacity) compared to newer battery technologies and the ability to provide high surge currents (an important factor in automobiles), Lead Acid Batteries are still the preferred choice of batteries in almost all vehicles. To charge a battery from AC we need a step down transformer, a rectifier, filtering circuit, regulator to maintain the constant voltage. Then we can give the regulated voltage to the battery to. Before seeing the working, let me show you how to calibrate the circuit. For calibrating the circuit, you need a variable DC Power Supply (a bench power supply). Set the voltage in your.