How to Use 3.7v LiPo 2200 mAh: Examples, Pinouts, and Specs

The MakerHawk Rechargeable LiPo Battery is a lightweight and high-capacity lithium polymer (LiPo) battery with a nominal voltage of 3.7V and a capacity of 2200 mAh. This battery is widely used in portable electronics, remote-controlled (RC) devices, IoT projects, and other applications requiring a compact, rechargeable power source. Its high energy density and stable discharge characteristics make it an excellent choice for powering small to medium-sized electronic devices.

• RC vehicles (drones, cars, boats, etc.)
• Wearable devices
• Portable electronics (e.g., handheld gaming consoles, cameras)
• DIY electronics and IoT projects
• Backup power for microcontroller-based systems (e.g., Arduino, Raspberry Pi)

The battery is equipped with a JST-XH 2-pin connector. Below is the pinout description:

1. Connection:

   • Connect the positive (+) pin of the battery to the positive power rail of your circuit.
   • Connect the negative (-) pin to the ground (GND) of your circuit.
   • Ensure the connector is securely attached to avoid loose connections.

2. Charging:

   • Use a LiPo-compatible charger with a constant current/constant voltage (CC/CV) charging profile.
   • Set the charging voltage to 4.2V and the charging current to 1.1A (recommended).
   • Avoid overcharging or discharging below 3.0V, as this can damage the battery.

3. Discharge:

   • Do not exceed the maximum discharge current of 4.4A.
   • Monitor the battery voltage during use to prevent over-discharge. Use a battery management system (BMS) or low-voltage cutoff circuit for safety.

4. Mounting:

   • Secure the battery in your project using a battery holder or adhesive tape to prevent movement or damage.

• Safety: Never puncture, short-circuit, or expose the battery to fire or water.
• Storage: Store the battery at room temperature, ideally at 40-60% charge, to prolong its lifespan.
• Balancing: If using multiple batteries in series, ensure they are balanced to avoid uneven charging/discharging.
• Protection Circuit: Use a protection circuit module (PCM) to safeguard against overcharging, over-discharging, and short circuits.

Below is an example of connecting the 3.7V LiPo battery to an Arduino UNO using a step-up converter to provide 5V:

• Connect the battery's positive terminal to the input of a step-up converter.
• Connect the step-up converter's output to the Arduino's 5V and GND pins.

// Example code to read battery voltage using an analog pin on Arduino UNO
// Assumes a voltage divider circuit is used to scale down the battery voltage

const int batteryPin = A0; // Analog pin connected to the voltage divider
const float voltageDividerRatio = 2.0; // Adjust based on your resistor values
const float referenceVoltage = 5.0; // Arduino UNO's reference voltage

void setup() {
  Serial.begin(9600); // Initialize serial communication
}

void loop() {
  int rawValue = analogRead(batteryPin); // Read the analog value
  float batteryVoltage = (rawValue / 1023.0) * referenceVoltage * voltageDividerRatio;

  // Print the battery voltage to the Serial Monitor
  Serial.print("Battery Voltage: ");
  Serial.print(batteryVoltage);
  Serial.println(" V");

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

1. Can I use this battery directly with a 5V device?

   • No, the battery's nominal voltage is 3.7V. Use a step-up converter to boost the voltage to 5V.

2. How do I know when the battery is fully charged?

   • The battery is fully charged when the charger indicates 4.2V on the output.

3. What happens if I over-discharge the battery?

   • Over-discharging can permanently damage the battery. Use a low-voltage cutoff circuit to prevent this.

4. Can I connect multiple batteries in series or parallel?

   • Yes, but ensure proper balancing and use a BMS to manage the pack safely.

By following these guidelines, you can safely and effectively use the MakerHawk 3.7V LiPo 2200 mAh battery in your projects.