How to Use sparkfun-battery-babysitter: Examples, Pinouts, and Specs

The SparkFun Battery Babysitter is an all-in-one battery management solution designed for single-cell lithium polymer (LiPo) batteries. It integrates protection circuits, charging capabilities, and a fuel gauge system to ensure that your battery operates safely and efficiently. This module is ideal for portable electronics, hobbyist projects, and any application where battery health and longevity are a concern.

• Portable electronic devices
• DIY electronics projects
• Remote sensors and IoT devices
• Robotics and unmanned vehicles
• Wearable technology

• Battery Chemistry: Lithium Polymer (LiPo)
• Charge Voltage: 4.2V (default)
• Charge Current: Programmable up to 500mA
• Operating Voltage: 3.0V to 5.5V
• Quiescent Current: <100µA
• Protection: Overcharge, overdischarge, overcurrent

1. Connecting the Battery:

   • Connect the positive terminal of the LiPo battery to the BAT pin.
   • Connect the negative terminal of the battery to the GND pin.

2. Setting the Charge Current:

   • The charge current can be set by connecting a resistor to the PROG pin. Refer to the datasheet for the appropriate resistor values.

3. Monitoring Battery Status:

   • The STAT1 and STAT2 pins can be used to monitor the charging status and battery health.

4. Interfacing with a Microcontroller:

   • Use the SDA and SCL pins to communicate with the fuel gauge via I2C.

5. Powering the System:

   • The SYS pin provides power to the system, which can be from the battery or USB, depending on the charging state.

• Ensure that the battery voltage and capacity are compatible with the Battery Babysitter.
• Avoid exposing the module to extreme temperatures and physical stress.
• Always disconnect the battery if the module will not be used for an extended period.
• Follow proper ESD precautions when handling the module to prevent damage.

• Battery Not Charging:

  • Check the battery connections and ensure the polarity is correct.
  • Verify that the charge current is set appropriately for your battery.

• No Power Output on SYS:

  • Ensure that the battery is charged and in good health.
  • Check for any signs of damage to the module or battery.

• Inaccurate Fuel Gauge Readings:

  • Calibrate the fuel gauge according to the battery's capacity and chemistry.
  • Allow the battery to go through a few charge/discharge cycles for better accuracy.

• Double-check all connections and solder joints for continuity and proper contact.
• Consult the datasheet for detailed information on setting up and calibrating the fuel gauge.
• Use a multimeter to measure the voltage at the BAT and SYS pins to ensure proper operation.

• Q: Can I use the Battery Babysitter with batteries other than LiPo?

  • A: The Battery Babysitter is designed specifically for single-cell LiPo batteries. Using other battery chemistries is not recommended.

• Q: How do I program the charge current?

  • A: The charge current is set by connecting a resistor to the PROG pin. The datasheet provides a table of resistor values for different charge currents.

• Q: What should I do if the module gets hot during operation?

  • A: If the module is overheating, immediately disconnect the battery and check for any issues with the charge current setting or battery condition.

#include <Wire.h>

// Define the I2C address for the Battery Babysitter
#define BATTERY_BABYSITTER_I2C_ADDRESS 0x76

void setup() {
  Wire.begin(); // Initialize I2C communication
  Serial.begin(9600); // Start serial communication at 9600 baud rate
}

void loop() {
  // Read battery voltage and state of charge from the Battery Babysitter
  Wire.beginTransmission(BATTERY_BABYSITTER_I2C_ADDRESS);
  // Request 2 bytes from the fuel gauge
  Wire.requestFrom(BATTERY_BABYSITTER_I2C_ADDRESS, 2); 
  while (Wire.available()) {
    byte highByte = Wire.read(); // Read the high byte
    byte lowByte = Wire.read(); // Read the low byte
    // Combine the two bytes to form the raw voltage value
    int rawVoltage = (int)highByte << 8 | lowByte; 
    // Convert the raw voltage to actual voltage (mV)
    float voltage = rawVoltage * 0.00125; 
    Serial.print("Battery Voltage: ");
    Serial.print(voltage);
    Serial.println(" V");
  }
  Wire.endTransmission();

  delay(1000); // Wait for 1 second before reading again
}

Note: The example code provided is a simple demonstration of how to read the battery voltage using the I2C communication protocol. For a complete implementation, including reading the state of charge and interfacing with the protection circuits, refer to the Battery Babysitter datasheet and example code provided by SparkFun.