DESIGN AND IMPLEMENTATION OF SMART CHARGING SYSTEM FOR LIFEPO4 BATTERY SOLAR CHARGER

• Main Author: Jeiba, Mario
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/82162
• Institution: Institut Teknologi Bandung

Solar is a renewable source of energy that is becoming increasingly more popular and important with the growing concerns of climate change worldwide. Photovoltaic (PV) solar panels have a nonlinear electrical characteristic dependent on solar irradiance, ambient temperature, and other factors that make efficient solar power generation more challenging. In addition, solar panels do not generate power at night. For this reason, various technologies are developed to overcome solar energy's shortcomings, such as maximum power point tracking (MPPT) for dynamic maximization of solar power generation, energy storage for reliable solar energy usage throughout changing sunlight conditions, smart charging for safe and reliable battery charging, and new battery chemistries such as lithium iron phosphate (LiFePO4) which feature greater cycle life to the more prevalent lithium ion (Li-ion) as well as reduced costs. Solar charger (SC) or solar charge controller (SCC) integrates technologies such as MPPT, smart charging, and even internet of things (IoT) to maximize solar panel energy transfer to the battery. This literature concerns the development of the LiFePO4 charge controller subsystem, as part of an SC device designed for residential applications and equipped with MPPT and IoT features. The charge controller implements the constant current-constant voltage (CC/CV) smart charging system for safe and reliable battery charging. The subsystem combines sensors and signal conditioning hardware with task and state machine-based software built on the ESP32 microcontroller. The charge controller works alongside the MPPT subsystem for power flow control and the IoT-enabled interface subsystem for device status communication via I2C. Implemented and integrated, the charge controller is capable of charging a battery to expectations. The subsystem charges to the solar panel's maximum power, including during testing with the solar panel simulated by a variable DC power supply. Several challenges need to be overcome, such as integration between device subsystems, communication with the device interface, and limited testing scope. The charge controller has been tested for the CV charging mode, but needs further testing for CC and MPPT modes.