Introduction

This project implements an IoT-based battery management system (BMS) prototype for monitoring and protecting battery cells in real time. The ESP32 microcontroller reads battery voltage through a precision voltage divider, current draw via the ACS712 sensor, and cell temperature using the MCP9808 I2C temperature sensor. The system detects charging states — identifying when the battery is charging, fully charged, or disconnected — and controls a relay-based load switch through physical push buttons. All readings including voltage, current, temperature (in both Celsius and Fahrenheit), and charging state are displayed on a 20x4 LCD and streamed to a Blynk IoT dashboard for remote monitoring. The system provides a complete battery health overview accessible from anywhere.

System Overview

Aim and Objectives

Aim:
Design and construct an IoT-enabled battery management system prototype for real-time voltage, current, and temperature monitoring with cloud-based remote access.

Objectives:

• Measure battery voltage using a precision voltage divider with calibrated ADC readings.
• Monitor charge/discharge current using ACS712 hall-effect current sensor.
• Track battery temperature with MCP9808 I2C sensor for thermal management.
• Detect and display charging state (Charging / Completed / Removed).
• Control load connection via relay with physical start/stop push buttons.
• Stream all battery parameters to Blynk IoT dashboard for remote monitoring.

Features & Deliverables

• Voltage Monitoring: Precision voltage divider provides accurate battery voltage measurement through ESP32 ADC.
• Current Sensing: ACS712 hall-effect sensor measures charge and discharge currents with bidirectional capability.
• Temperature Tracking: MCP9808 high-accuracy I2C sensor reports both Celsius and Fahrenheit readings.
• Charging State Detection: Intelligent algorithm classifies battery as Charging, Completed, or Removed based on current flow.
• Load Control: Relay module with push button interface for manual load connect/disconnect.
• Blynk Dashboard: Virtual pins V0-V4 stream voltage, current, temperature, and state to cloud dashboard.
• LCD Display: 20x4 local display shows all parameters for direct monitoring without network dependency.

Process / Methodology

Hardware Assembly

Components: ESP32, ACS712, Voltage Divider Resistors, MCP9808, 20x4 I2C LCD, Relay Module, Push Buttons, LEDs.

• Designed precision voltage divider for battery voltage scaling to ESP32 ADC range.
• Connected ACS712 current sensor in series with battery for current measurement.
• Wired MCP9808 via I2C bus alongside LCD for temperature monitoring.
• Integrated relay module with start/stop buttons for load switching control.

Software Development

• Developed ESP32 firmware with multi-sensor polling on 2-second interval.
• Implemented charging state detection algorithm based on current magnitude and direction.
• Configured Blynk virtual pins for voltage (V0), current (V1), temperature (V2/V3), and state (V4).
• Added WiFi connection management with status LED indication.

Testing & Calibration

• Calibrated voltage divider ratio against precision multimeter readings.
• Validated ACS712 zero-current offset and sensitivity calibration.
• Tested charging state transitions across charge/discharge/disconnect scenarios.

Challenges & Solutions

• Challenge: ESP32 ADC nonlinearity affecting voltage measurement accuracy.
  Solution: Applied calibration factor and used multisampling with averaging for stable readings.
• Challenge: ACS712 zero-current offset drift with temperature changes.
  Solution: Implemented startup baseline calibration routine to capture zero-current reference.
• Challenge: I2C bus contention between LCD and MCP9808 sensor.
  Solution: Added proper pull-up resistors and sequential I2C transaction scheduling.

Results & Impact

• Battery Visibility: Complete real-time view of battery health parameters for informed management.
• Remote Access: Blynk dashboard enabled battery monitoring from any location via smartphone.
• State Awareness: Charging state detection prevented overcharging and informed maintenance.
• Load Protection: Relay control with manual switches provided safe load management.

Future Enhancements

• Add cell balancing for multi-cell battery pack management.
• Implement SoC (State of Charge) estimation using coulomb counting.
• Add over-voltage, under-voltage, and over-temperature protection with auto-disconnect.
• Support multiple battery chemistry profiles (Li-ion, LiFePO4, Lead-Acid).

Demonstration / Access

• GitHub Repository: Coming soon
• Live Demonstration Video: Coming soon

Thank You for Visiting My Portfolio

I sincerely appreciate you taking the time to explore my portfolio and learn about my work and expertise. If you have any questions or wish to discuss potential collaborations, please feel free to reach out via the Contact section.

Best regards,
Damilare Lekan, Adekeye.