How to Use BATERIA 18650 X2: Examples, Pinouts, and Specs

The BATERIA 18650 X2 is a configuration of two rechargeable lithium-ion 18650 cells. Each cell provides a nominal voltage of 3.7V and a capacity typically ranging from 1800mAh to 3500mAh. When combined, these cells can be connected in series to increase voltage or in parallel to increase capacity, making them highly versatile for various applications.

Commonly used in portable electronics, power banks, flashlights, and DIY projects, the BATERIA 18650 X2 is valued for its high energy density, rechargeability, and long cycle life. It is also a popular choice for robotics, electric vehicles, and renewable energy storage systems.

Below are the key technical details for the BATERIA 18650 X2:

The BATERIA 18650 X2 does not have traditional pins but instead features terminals for electrical connections. The configuration depends on whether the cells are connected in series or parallel:

1. Determine the Configuration: Decide whether to connect the cells in series (for higher voltage) or parallel (for higher capacity). Ensure the cells are of the same type and charge level.
2. Use a Battery Holder: For safety and convenience, use a battery holder designed for two 18650 cells. This ensures proper alignment and connection.
3. Connect to a Protection Circuit: Lithium-ion batteries require a Battery Management System (BMS) or protection circuit to prevent overcharging, over-discharging, and short circuits.
4. Charging: Use a lithium-ion battery charger with a constant current/constant voltage (CC/CV) profile. Ensure the charger matches the configuration (e.g., 8.4V for series or 4.2V for parallel).
5. Load Connection: Connect the load to the positive and negative terminals of the battery pack. Ensure the load does not exceed the maximum discharge current.

• Safety First: Always use a BMS to protect the cells from damage and ensure safe operation.
• Avoid Overcharging: Do not exceed 4.2V per cell during charging.
• Avoid Deep Discharge: Do not discharge below 2.5V per cell to prevent damage.
• Temperature Monitoring: Avoid using the battery in extreme temperatures (below -20°C or above 60°C).
• Storage: Store the battery at 40-60% charge in a cool, dry place if not in use for extended periods.

To power an Arduino UNO with the BATERIA 18650 X2 in series (7.4V), you can use a voltage regulator to step down the voltage to 5V. Below is an example circuit and code:

1. Connect the positive terminal of the battery pack to the input of a 7805 voltage regulator.
2. Connect the output of the 7805 regulator to the 5V pin of the Arduino UNO.
3. Connect the negative terminal of the battery pack to the GND pin of the Arduino UNO.

// Example code to blink an LED using Arduino UNO powered by BATERIA 18650 X2
// Ensure the battery pack is connected via a voltage regulator to provide 5V.

const int ledPin = 13; // Built-in LED pin on Arduino UNO

void setup() {
  pinMode(ledPin, OUTPUT); // Set LED pin as output
}

void loop() {
  digitalWrite(ledPin, HIGH); // Turn the LED on
  delay(1000);               // Wait for 1 second
  digitalWrite(ledPin, LOW);  // Turn the LED off
  delay(1000);               // Wait for 1 second
}

1. Battery Not Charging:

   • Cause: Faulty charger or protection circuit.
   • Solution: Check the charger output voltage and ensure it matches the battery configuration. Verify the BMS is functioning correctly.

2. Battery Drains Quickly:

   • Cause: High self-discharge rate or excessive load.
   • Solution: Test the cells individually for capacity. Reduce the load or replace degraded cells.

3. Overheating During Use:

   • Cause: Excessive current draw or poor ventilation.
   • Solution: Ensure the load does not exceed the maximum discharge current. Improve ventilation around the battery.

4. No Output Voltage:

   • Cause: Protection circuit triggered due to over-discharge or short circuit.
   • Solution: Recharge the battery to reset the protection circuit.

Q: Can I use different 18650 cells in the same pack?
A: No, always use identical cells with the same capacity, voltage, and charge level to avoid imbalance and potential damage.

Q: How do I know if the battery is fully charged?
A: The charger will typically indicate full charge when the voltage reaches 4.2V per cell.

Q: Can I connect more than two 18650 cells?
A: Yes, but ensure proper balancing and use a BMS designed for the specific configuration.

Q: Is it safe to solder directly to 18650 cells?
A: Direct soldering is not recommended as excessive heat can damage the cells. Use spot welding or pre-tabbed cells instead.