How to Use 12v 8.5A Power Supply: Examples, Pinouts, and Specs

The MeanWell LRS-100-12 is a compact and reliable AC-to-DC power supply designed to deliver a stable 12V DC output with a maximum current of 8.5A. This power supply is ideal for powering a wide range of electronic devices, including LED lighting systems, industrial control systems, single-board computers, and other low-voltage applications. Its robust design ensures high efficiency, low power consumption, and long-term reliability.

• LED lighting systems and displays
• Industrial automation and control systems
• Single-board computers (e.g., Raspberry Pi, Arduino projects)
• Security systems and surveillance cameras
• DIY electronics and prototyping projects

The following table outlines the key technical specifications of the MeanWell LRS-100-12 power supply:

The MeanWell LRS-100-12 features screw terminal connections for input and output. The pin configuration is as follows:

1. Mounting the Power Supply: Secure the power supply in a well-ventilated area to ensure proper heat dissipation. Avoid enclosing it in a sealed box without ventilation.
2. Connecting the Input:
   • Connect the AC live wire to the L terminal.
   • Connect the AC neutral wire to the N terminal.
   • Optionally, connect the earth wire to the FG terminal for safety.
3. Connecting the Output:
   • Connect the V+ terminal to the positive input of your load or circuit.
   • Connect the V- terminal to the ground or negative input of your load or circuit.
4. Adjusting the Output Voltage (if needed):
   • Use the built-in potentiometer to fine-tune the output voltage. This is useful for applications requiring slight voltage adjustments.
5. Powering On:
   • Ensure all connections are secure and correct.
   • Plug the power supply into an AC outlet and switch it on.

• Load Requirements: Ensure the total load does not exceed 8.5A or 102W to prevent overloading the power supply.
• Ventilation: Operate the power supply in a well-ventilated area to avoid overheating.
• Safety: Always disconnect the power supply from the AC source before making any wiring changes.
• Fusing: Consider adding a fuse on the AC input line for additional protection.
• Arduino Compatibility: The 12V output can be used to power an Arduino UNO via its VIN pin. Use a voltage regulator or step-down converter if a lower voltage is required.

To power an Arduino UNO using the MeanWell LRS-100-12:

1. Connect the V+ terminal to the Arduino's VIN pin.
2. Connect the V- terminal to the Arduino's GND pin.

Here is an example Arduino sketch to blink an LED when powered by the LRS-100-12:

// Blink an LED connected to pin 13
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 Output Voltage:

   • Check the AC input connections (L and N) and ensure the power supply is receiving power.
   • Verify that the load is properly connected to the V+ and V- terminals.
   • Inspect the built-in fuse for damage and replace if necessary.

2. Overheating:

   • Ensure the power supply is not overloaded (maximum 8.5A).
   • Check for proper ventilation and avoid operating in high-temperature environments.

3. Voltage Fluctuations:

   • Use the potentiometer to fine-tune the output voltage.
   • Ensure the input voltage is within the specified range (85-264V AC).

4. Short Circuit Protection Triggered:

   • Disconnect the load and inspect for short circuits.
   • After resolving the issue, reconnect the load and power on the supply.

Q: Can I use this power supply to charge a 12V battery?
A: While the LRS-100-12 can provide 12V DC, it is not designed as a battery charger. Use a dedicated battery charger for safe and efficient charging.

Q: Is the power supply suitable for outdoor use?
A: No, the LRS-100-12 is not weatherproof. It should be used in indoor environments or within a weatherproof enclosure.

Q: Can I connect multiple LRS-100-12 units in parallel for higher current?
A: No, the LRS-100-12 is not designed for parallel operation. Use a higher-capacity power supply if more current is required.

Q: How do I know if the power supply is overloaded?
A: The power supply includes overload protection. If overloaded, it will reduce the output or shut down to protect itself. Reduce the load and restart the power supply.