How to Use Adafruit Micro Lipo Charger: Examples, Pinouts, and Specs

The Adafruit Micro Lipo Charger is a compact, versatile charging module specifically designed for lithium polymer (LiPo) batteries. This user-friendly device simplifies the process of charging small LiPo batteries by integrating power management circuitry and enabling charging through a USB connection. It is ideal for DIY electronics enthusiasts and professionals who require a reliable power source for portable projects.

• Portable electronics
• Wearable devices
• DIY projects
• Drones and RC vehicles
• Prototyping battery-powered gadgets

• Input Voltage: 3.7V to 5.5V via USB
• Charge Current: 100mA (default) or 500mA (selectable)
• Battery Voltage: 3.7V nominal (single cell)
• Charge Cutoff Voltage: 4.2V ± 1%
• Operating Temperature: -40°C to +85°C

1. Connect the Battery:

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

2. Power the Charger:

   • Supply 5V to the 5V pin from a USB power source.
   • Connect the ground of the power source to the GND pin adjacent to the 5V pin.

3. Select Charge Current:

   • The default charge current is set to 100mA. To select 500mA, solder the closed jumper provided on the board.

4. Monitor Charging Status:

   • The STAT pin can be connected to an LED or a microcontroller to monitor the charging status.

• Ensure the polarity of the battery is correct to prevent damage.
• Do not exceed the recommended input voltage range.
• Avoid charging batteries that are not rated for the selected current.
• Use a quality USB power source to ensure stable charging.
• Do not leave batteries unattended while charging.

• LED Not Lighting Up:

  • Check the USB power source and connections.
  • Ensure the battery is properly connected with correct polarity.

• Battery Not Charging:

  • Verify that the battery is in good condition and within its lifecycle.
  • Check if the solder jumper for charge current is properly set.

• Double-check all connections for solid contact and correct orientation.
• Use a multimeter to verify the voltage at the BAT and GND pins.
• If the STAT pin does not indicate charging, ensure the battery voltage is below the charge cutoff voltage.

• Q: Can I charge multiple batteries at once?

  • A: No, the charger is designed for single-cell LiPo batteries.

• Q: What does the STAT pin indicate?

  • A: The STAT pin can be used to indicate the charging status. When charging, it can be connected to an LED that will light up; when charging is complete, the LED will turn off.

• Q: Is it safe to leave the battery connected to the charger after charging is complete?

  • A: Yes, the charger has built-in power management that prevents overcharging.

// Example code to monitor Adafruit Micro Lipo Charger's STAT pin using Arduino UNO

const int STATpin = 2; // Connect STAT pin to digital pin 2 on Arduino

void setup() {
  pinMode(STATpin, INPUT); // Set STAT pin as input
  Serial.begin(9600); // Start serial communication at 9600 baud
}

void loop() {
  int chargingStatus = digitalRead(STATpin); // Read the STAT pin status

  if (chargingStatus == HIGH) {
    // If STAT pin is HIGH, battery is still charging
    Serial.println("Battery is charging...");
  } else {
    // If STAT pin is LOW, battery is fully charged
    Serial.println("Battery is fully charged.");
  }

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

Remember to keep the code comments concise and within the 80 character line length limit. This example demonstrates how to use an Arduino UNO to monitor the charging status of a LiPo battery connected to the Adafruit Micro Lipo Charger.