How to Use 4S 100A LiFePO4 Battery Balance Charging Protection BMS Module: Examples, Pinouts, and Specs

The 4S 100A LiFePO4 Battery Balance Charging Protection BMS Module is a critical component for managing 4-series lithium iron phosphate (LiFePO4) battery packs. It ensures safe and efficient operation by providing balance charging, overcharge protection, over-discharge protection, and short-circuit protection. This module is designed to maintain the health and longevity of LiFePO4 batteries, making it an essential part of battery-powered systems.

• Electric vehicles (e-bikes, e-scooters, etc.)
• Solar energy storage systems
• Uninterruptible power supplies (UPS)
• Portable power stations
• Robotics and industrial equipment

The following table outlines the key technical details of the 4S 100A LiFePO4 BMS module:

The module has several key connections for proper operation. The table below describes each pin:

1. Connect the Battery Pack:

   • Connect the B- pin to the negative terminal of the battery pack.
   • Connect the B1, B2, and B3 pins to the positive terminals of the first, second, and third cells, respectively.
   • Connect the B+ pin to the positive terminal of the battery pack.

2. Connect the Load and Charger:

   • Connect the P- pin to the negative terminal of the load and charger.
   • Connect the P+ pin to the positive terminal of the load and charger.

3. Ensure Proper Wiring:

   • Double-check all connections to ensure they are secure and correctly aligned with the pin configuration.

4. Power On:

   • Once all connections are made, the BMS module will automatically manage the battery pack, providing balance charging and protection.

• Cell Matching: Ensure all cells in the battery pack have similar capacities and internal resistances to avoid imbalance.
• Heat Dissipation: The module may generate heat during operation. Ensure proper ventilation or heat sinking to prevent overheating.
• Avoid Overloading: Do not exceed the maximum continuous current rating of 100A to prevent damage to the module.
• Wiring Order: Always connect the B- pin first, followed by the B1, B2, B3, and B+ pins. Disconnect in reverse order.

While the BMS module itself does not directly interface with an Arduino, you can monitor the battery pack's voltage using an Arduino UNO and a voltage divider circuit. Below is an example code snippet for monitoring the voltage of a single cell:

// Define the analog pin connected to the voltage divider
const int voltagePin = A0;

// Define the voltage divider ratio (adjust based on your resistor values)
const float voltageDividerRatio = 5.0; // Example: 100k and 20k resistors

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

void loop() {
  // Read the analog value from the voltage divider
  int analogValue = analogRead(voltagePin);

  // Convert the analog value to voltage
  float voltage = (analogValue * 5.0 / 1023.0) * voltageDividerRatio;

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

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

Note: Use appropriate resistor values in the voltage divider to ensure the input voltage to the Arduino does not exceed 5V.

1. Module Overheating:

   • Cause: Excessive current draw or poor ventilation.
   • Solution: Reduce the load current or improve heat dissipation with a heatsink or fan.

2. Battery Pack Not Charging:

   • Cause: Incorrect wiring or damaged cells.
   • Solution: Verify all connections and check the health of each cell in the battery pack.

3. Imbalanced Cells:

   • Cause: Cells with different capacities or internal resistances.
   • Solution: Replace mismatched cells or manually balance the cells before connecting to the BMS.

4. No Output Voltage:

   • Cause: Over-discharge protection triggered.
   • Solution: Recharge the battery pack to reset the protection circuit.

Q: Can this BMS module be used with other battery chemistries?
A: No, this module is specifically designed for LiFePO4 batteries and should not be used with other chemistries.

Q: What happens if I exceed the 100A current limit?
A: Exceeding the current limit may damage the module or trigger the short-circuit protection.

Q: How do I know if the module is balancing the cells?
A: The module automatically balances the cells when their voltages differ. You can measure the individual cell voltages to confirm balancing.

Q: Can I use this module for a 3-series or 5-series battery pack?
A: No, this module is designed specifically for 4-series configurations. Using it with other configurations may result in improper operation or damage.