How to Use Adafruit LiPoly Backpack: Examples, Pinouts, and Specs

The Adafruit LiPoly Backpack is an essential component for hobbyists and professionals looking to integrate a rechargeable power source into their projects. This compact module not only provides a charging solution for lithium polymer (LiPo) batteries but also includes protection circuitry and a power supply option via a USB port. It is commonly used in portable electronics, wearables, and IoT devices where a reliable and rechargeable power source is required.

• Input Voltage (for charging): 5V via micro USB
• Battery Voltage: 3.7V nominal (for standard LiPo batteries)
• Charge Current: 100mA by default, adjustable up to 500mA
• Output Voltage: 3.7V to 5V (boost converter output)
• Maximum Output Current: 500mA (depends on battery capacity)
• Protection: Overcharge and over-discharge protection

1. Connecting the Battery:

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

2. Powering Your Project:

   • Use the 5V pin to power your project. This pin provides a regulated output from the boost converter.

3. Charging the Battery:

   • Connect a micro USB cable to the USB port and a 5V USB power source to charge the battery.

4. Enabling/Disabling the Regulator:

   • The regulator can be enabled or disabled using the EN pin. Connect it to a high logic level to enable or leave it floating/disconnected to disable.

• Battery Safety: Always use LiPo batteries with a protection circuit and never leave them charging unattended.
• Charging Current: The default charging current is 100mA. To adjust the current, you may need to replace the onboard resistor with the appropriate value.
• Output Load: Ensure that the load connected to the 5V pin does not exceed the maximum output current rating.
• Heat Dissipation: Be mindful of heat generation when charging or when powering high-current loads.

• Battery Not Charging:

  • Ensure the micro USB cable is properly connected and the power source is on.
  • Check the battery connections to the BAT and GND pins.
  • Verify that the battery is not already fully charged.

• No Output Voltage:

  • Check if the EN pin is set to a high logic level.
  • Ensure that the battery is properly charged and connected.
  • Inspect the 5V pin and the connected load for any shorts or open circuits.

• If the battery is not charging, try a different USB cable or power source.
• If the output voltage is not present, ensure that the EN pin is not accidentally grounded.
• For any persistent issues, refer to the Adafruit support forums or contact technical support.

// Example code to read the battery voltage using an Arduino UNO

const int batteryPin = A0; // Analog pin connected to voltage divider output

void setup() {
  Serial.begin(9600);
}

void loop() {
  int sensorValue = analogRead(batteryPin); // Read the analog value
  float voltage = sensorValue * (5.0 / 1023.0); // Convert to voltage
  Serial.print("Battery Voltage: ");
  Serial.println(voltage);
  delay(1000); // Wait for a second before reading again
}

Note: This code assumes you have a voltage divider connected to the BAT pin to bring the battery voltage within the range of the Arduino analog input. Adjust the voltage divider values accordingly.

Remember to keep code comments concise and within the 80 character line length limit.