300W 20A Buck Converter Step Down Module Constant Current LED Driver DC-DC

Specifications

• Input Voltage Range: 6V to 40V DC
• Output Voltage Range: 1.2V to 36V DC (Continuously Adjustable)
• Maximum Output Current: 20A (15A continuous recommended; external fan required for max load)
• Maximum Power Output: 300W
• Conversion Efficiency: Up to 96%
• Switching Frequency: 150KHz
• Voltage Regulation: ±0.5%
• Current Regulation: ±0.5%
• Operating Temperature: -10°C to +60°C
• Dimensions: Approx. 60 x 53 x 27 mm
• Features: Constant Voltage (CV) and Constant Current (CC) potentiometers, Short circuit protection (limit 20A).

Applications

• High-Power LED Driving: Perfectly regulates current for 50W, 100W, or 200W COB LED chips.
• Custom Battery Chargers: Ideal for safely charging Lithium-ion, LiFePO4, or Lead-Acid battery banks using the CC/CV feature.
• Variable Bench Power Supply: Build your own heavy-duty lab power supply for a fraction of the cost.
• Solar Power Regulation: Step down fluctuating solar panel voltages to a stable output for batteries or electronics.
• Robotics & Motors: Power large DC motors, actuators, or multi-rotor drones that require massive current spikes.

Unlock New Capabilities

• Past Projects: If you've mastered basic power regulation using smaller LM2596 or XL4015 modules, you know their limits (usually 3A to 5A max).
• The Upgrade: This 300W module unlocks heavy lifting. You can now drive massive LED arrays, build custom e-bike battery chargers, or power large CNC stepper motors without the magic smoke escaping.
• Effort Level: Intermediate. You will need a multimeter to calibrate the CC/CV potentiometers before connecting your load. Heavy-gauge wire (14AWG or thicker) is strictly required.

Virtual Technician & Wiring Guide

• ⚠️ CRITICAL WARNING: This module DOES NOT have reverse polarity protection. Reversing the input wires will instantly destroy the board. Always double-check polarity before applying power. Probots Lab Verified testing confirms you must use an external cooling fan if pulling more than 15A continuously.

Wiring Pinout:

• IN+: Connect to Positive (+) of your Power Source (e.g., 24V Battery)
• IN-: Connect to Negative (-) of your Power Source
• OUT+: Connect to Positive (+) of your Load (e.g., LED, Motor)
• OUT-: Connect to Negative (-) of your Load
• CV Potentiometer: Turn clockwise to increase output voltage.
• CC Potentiometer: Turn clockwise to increase the current limit.

Package Include:

• 1 x 300W 20A Constant Current Adjustable Buck Converter Step-Down Voltage Module

Frequently Asked Questions (FAQ)

• What is the maximum input voltage for this buck converter?
  The maximum safe input voltage is 40V DC. Exceeding this will damage the input capacitors and switching IC.
• Can this module step up the voltage?
  No, this is strictly a "buck" (step-down) converter. The output voltage will always be lower than the input voltage.
• Does it have reverse polarity protection?
  No. Connecting the power backwards on the input terminals will instantly destroy the module. Always verify polarity.
• How do I adjust the output voltage?
  Connect a multimeter to the output terminals (without a load connected) and turn the CV (Constant Voltage) potentiometer with a flathead screwdriver until you reach the desired voltage.
• How do I set the constant current (CC) limit?
  First, set the desired voltage. Then, turn the CC potentiometer counter-clockwise about 30 turns. Connect your multimeter (in 10A or 20A current mode) directly across the output to create a short circuit. Finally, turn the CC pot clockwise until the multimeter reads your desired current limit.
• Can I use this to charge a 12V car battery?
  Yes. You can input 18V-24V, set the CV to 14.4V, and set the CC to a safe charging current for your specific lead-acid battery.
• Can I charge lithium-ion or LiFePO4 battery packs with this?
  Yes, the CC/CV functionality makes it perfect for charging lithium battery packs. Just ensure you set the exact maximum charge voltage and current limit required by your battery chemistry.
• Do I need an external cooling fan?
  If you are drawing less than 10A-15A, the passive heatsinks are usually sufficient. For continuous loads above 15A or 200W, an external cooling fan is absolutely required to prevent thermal shutdown.
• What happens if I short the output?
  The module has short-circuit protection. It will limit the current to whatever value you have set on the CC potentiometer.
• Why is my output voltage not changing when I turn the potentiometer?
  These are multi-turn potentiometers. It may take 10 to 20 full rotations before you see the voltage begin to change. Keep turning!
• Can I power a 100W LED chip with this?
  Absolutely. This is one of the best modules for high-power LEDs. Just ensure you set the CC limit to match the LED's specifications to prevent thermal runaway.
• What gauge wire should I use for 20A?
  We strongly recommend using 14 AWG or 12 AWG silicone stranded wire to safely handle 20A without the wires melting.
• Is the output isolated from the input?
  No, this is a non-isolated buck converter. The input and output share a common ground reference internally.
• Can I connect two of these in parallel for 40A?
  It is not recommended to connect the outputs directly in parallel as slight voltage differences will cause one module to take the entire load.
• What is the switching frequency of this module?
  The module operates at a switching frequency of 150KHz, which allows for smaller inductors and efficient power conversion.
• Can I use this with a solar panel?
  Yes, it can step down solar panel voltage. However, it does not have MPPT (Maximum Power Point Tracking) logic, so it will simply act as a standard voltage regulator.
• Does it have a low voltage cutoff to protect batteries from over-discharging?
  No, this module does not have under-voltage lockout (UVLO). If powering it from a battery, you need a separate battery protection BMS.
• Why does the inductor get hot during operation?
  It is normal for the toroidal inductor to get warm or hot under heavy loads due to magnetic core losses and copper resistance. Add a fan if it gets too hot to touch.