How to Use XH-M609 LVD Relay Battery Low Voltage Protection: Examples, Pinouts, and Specs

The XH-M609 is a low voltage disconnect (LVD) relay module designed to protect batteries from over-discharge. It monitors the battery voltage in real-time and automatically disconnects the load when the voltage drops below a user-defined threshold. This feature helps prevent damage to the battery, extends its lifespan, and ensures reliable operation in various applications.

• Solar power systems
• Uninterruptible power supplies (UPS)
• Battery-powered devices
• Automotive and RV battery protection
• Off-grid energy systems

Below are the key technical details and pin configuration for the XH-M609 module:

1. Connect the Battery:

   • Connect the positive terminal of the battery to the BAT+ pin.
   • Connect the negative terminal of the battery to the BAT- pin.

2. Connect the Load:

   • Connect the positive terminal of the load to the LOAD+ pin.
   • Connect the negative terminal of the load to the LOAD- pin.

3. Power On the Module:

   • Once the battery is connected, the module will power on, and the LED display will show the current battery voltage.

4. Set the Low Voltage Threshold:

   • Press and hold the SET button until the display starts flashing.
   • Use short presses of the SET button to adjust the low voltage disconnect threshold.
   • Wait for a few seconds without pressing any buttons to save the setting.

5. Operation:

   • The module will monitor the battery voltage in real-time.
   • If the voltage drops below the set threshold, the relay will disconnect the load to protect the battery.
   • When the voltage rises above the threshold (plus a small hysteresis), the relay will reconnect the load.

• Ensure the battery voltage is within the module's operating range (10.0V - 14.0V).
• Do not exceed the maximum load current of 10A to avoid damaging the relay.
• Use appropriately sized wires for the battery and load connections to minimize voltage drops.
• Place the module in a well-ventilated area to prevent overheating.
• Regularly check the connections to ensure they are secure and free of corrosion.

While the XH-M609 operates independently, it can be monitored using an Arduino UNO for additional functionality, such as logging battery voltage or triggering alerts. Below is an example code snippet:

// Example: Reading battery voltage from XH-M609 using Arduino UNO
// Connect the BAT+ terminal to an analog input pin on the Arduino
// Ensure a voltage divider is used if the battery voltage exceeds 5V

const int analogPin = A0;  // Analog pin connected to BAT+ (via voltage divider)
float voltage = 0.0;       // Variable to store the calculated voltage

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

void loop() {
  int sensorValue = analogRead(analogPin);  // Read the analog input
  voltage = sensorValue * (5.0 / 1023.0);  // Convert to voltage (adjust for divider)
  
  // Print the voltage to the Serial Monitor
  Serial.print("Battery Voltage: ");
  Serial.print(voltage);
  Serial.println(" V");
  
  delay(1000);  // Wait 1 second before the next reading
}

Note: If the battery voltage exceeds 5V, use a voltage divider to step it down to a safe range for the Arduino's analog input pins.

1. Can the XH-M609 be used with a 24V battery?
   No, the module is designed for 12V systems only. Using it with a 24V battery may damage the module.

2. What happens if the load exceeds 10A?
   Exceeding the maximum load current can damage the relay. Use an external relay or contactor for higher current loads.

3. Can I use the XH-M609 with a lithium-ion battery?
   Yes, but ensure the low voltage threshold is set according to the battery's specifications to avoid over-discharge.

4. How do I reset the module to factory settings?
   Press and hold the SET button for 10 seconds to reset the module to its default settings.

By following this documentation, you can effectively use the XH-M609 to protect your battery and ensure reliable operation in your projects.