This document describes the development of an IoT-based smart battery management system for a 1s and 3s lithium-ion battery pack intended for e-bike applications. The system measures voltage, current, and temperature of each cell and transmits the data to the cloud for analysis to detect faulty cells. It also implements passive cell balancing. The system was tested on a 3-cell nickel manganese cobalt oxide battery pack and successfully identified faulty cells and performed balancing.