Intelligent 3-stage MPPT lead acid battery auto charger

This document reports an update of a programmable intelligent three-stage lead acid battery charger that was published by the authors, where the traditional linear power regulator is replaced by an advanced buck-converter. This works as a programmable and variable switching regulator, which varies the output automatically as per the programmed logic for charging batteries. This update monitors the input and then sets the output instead of a constant input predefined. As a switching regulator, it also increases the over-all efficiency than traditional chargers. The reference design discussed here is from the previous work, having the freewheeling diode replaced by an n-MOSFET and the p-MOSFET replaced by another n-MOSFET for gate to improve efficiency. This design will help to develop a PV charger for the lead acid batteries that will harness maximum power out of the PV-array along with taking the best care of the battery by following the battery chemistry rules. Overall, this device is highly efficient, low cost and manufacturable with most commonly available components in the market of Bangladesh.