How to Use 2 x 18650 in case: Examples, Pinouts, and Specs

The 2 x 18650 Battery Holder is a compact and durable enclosure designed to securely hold two 18650 lithium-ion batteries. It provides a convenient way to power electronic circuits and devices, offering a stable and portable power source. This holder is commonly used in DIY electronics, robotics, IoT projects, and portable devices where a reliable power supply is essential.

• Powering Arduino, Raspberry Pi, and other microcontroller-based projects
• Robotics and motorized systems
• Portable electronic devices
• IoT and wireless sensor networks
• LED lighting systems

The following table outlines the key technical details of the 2 x 18650 Battery Holder:

The battery holder typically has two wires for connection:

Ensure proper polarity when connecting the wires to your circuit to avoid damage to components.

1. Insert Batteries: Place two 18650 lithium-ion batteries into the holder, ensuring correct polarity. The positive and negative terminals of the batteries should align with the "+" and "-" markings on the holder.
2. Connect Wires: Use the red (positive) and black (negative) wires to connect the holder to your circuit. Ensure the connections are secure.
3. Choose Wiring Configuration:
   • If the holder is wired in series, the output voltage will be the sum of the two batteries (e.g., 7.4V for two 3.7V batteries).
   • If the holder is wired in parallel, the output voltage will remain the same as a single battery (e.g., 3.7V), but the capacity (mAh) will double.
4. Add Protection Circuitry: For safety, consider adding a battery management system (BMS) or a protection circuit to prevent overcharging, over-discharging, and short circuits.

• Battery Selection: Use only high-quality, protected 18650 batteries to ensure safety and performance.
• Polarity Check: Always double-check the polarity of the batteries and connections before powering your circuit.
• Heat Management: Avoid overloading the batteries, as excessive current draw can cause overheating.
• Storage: Remove the batteries from the holder when not in use for extended periods to prevent leakage or discharge.

To power an Arduino UNO using the 2 x 18650 Battery Holder, follow these steps:

1. Insert two 18650 batteries into the holder.
2. Connect the red wire (positive) to the VIN pin on the Arduino UNO.
3. Connect the black wire (negative) to the GND pin on the Arduino UNO.

Here is a simple Arduino sketch to blink an LED while powered by the battery holder:

// Simple LED Blink Example
// This code blinks an LED connected to pin 13 of the Arduino UNO.
// Ensure the Arduino is powered by the 2 x 18650 Battery Holder.

void setup() {
  pinMode(13, OUTPUT); // Set pin 13 as an output
}

void loop() {
  digitalWrite(13, HIGH); // Turn the LED on
  delay(1000);            // Wait for 1 second
  digitalWrite(13, LOW);  // Turn the LED off
  delay(1000);            // Wait for 1 second
}

1. No Power Output

   • Cause: Batteries are inserted incorrectly or are depleted.
   • Solution: Check the polarity of the batteries and replace them if necessary.

2. Overheating

   • Cause: Excessive current draw or short circuit.
   • Solution: Ensure the circuit's current requirements are within the battery's discharge rating. Check for short circuits.

3. Loose Connections

   • Cause: Wires or battery contacts are not secure.
   • Solution: Ensure the wires are firmly connected and the batteries are seated properly.

4. Voltage Drop

   • Cause: Batteries are nearing depletion or have a high internal resistance.
   • Solution: Replace the batteries with fully charged ones or use high-quality cells.

Q: Can I use the holder with only one 18650 battery?
A: Yes, but the output voltage will be limited to the voltage of a single battery (3.7V nominal).

Q: Is the holder waterproof?
A: No, the holder is not waterproof. Avoid exposing it to moisture or water.

Q: Can I charge the batteries while they are in the holder?
A: Only if the holder is connected to a compatible charging circuit. Otherwise, remove the batteries and charge them using a dedicated charger.

Q: What is the maximum current the holder can handle?
A: The maximum current depends on the quality of the holder's contacts and the batteries used. Typically, it can handle up to 20A with high-quality batteries.

By following this documentation, you can safely and effectively use the 2 x 18650 Battery Holder in your electronic projects.