Overview
12V DC Temperature Controller for Refrigeration & Cooling Applications
The YeloDeer STC-201 is a compact microcomputer temperature controller designed for 12V DC refrigeration and cooling control systems. It is built for applications that need stable temperature control, compressor protection, defrost control, and easy temperature adjustment in a low-voltage DC setup.
This controller is suitable for RV refrigerators, camper cooling systems, small freezers, portable coolers, beverage coolers, display cabinets, cold storage cabinets, and DIY low-voltage refrigeration projects.
It supports:
Temperature control for cooling systems
Compressor delay protection
Automatic defrost control
Manual defrost control
High and low temperature alarm settings
°F / °C display switching
Auto-lock function to help prevent accidental setting changes
NTC temperature sensor input
Why Choose This Controller?
Choose this 12V DC temperature controller if you need:
A compact controller for RV refrigerator or camper cooling projects
A controller for small freezer, portable cooler, or beverage cooler systems
Compressor output control with delay protection
Defrost output control for frost management
Adjustable alarm settings for high or low temperature conditions
A Fahrenheit-default controller with °F / °C switching
A low-voltage controller for DIY refrigeration builds
Important Before You Order
Please confirm the following before purchase:
Your system uses 12V DC power.
Do not connect this controller to AC power.
Your compressor, fan, defrost heater, or connected load is compatible with the relay output.
The 30A and 10A relay ratings are resistive load ratings. Actual allowable working current may be lower for inductive loads such as compressors, motors, or fans.
Proper circuit protection should be used according to your system design.
This product is intended for general temperature control applications only. It is not intended for life-support, medical compliance, or other critical storage applications.
Applications & Compatibility
Recommended Applications
This 12V DC temperature controller is suitable for:
RV refrigerators
Camper cooling systems
Small freezers
Portable cooling boxes
Beverage coolers
Display cabinets
Cold storage cabinets
Fruit and vegetable fresh-keeping cabinets
Mushroom cultivation or growing chambers
DIY low-voltage refrigeration systems
Other 12V DC cooling control applications
Cooling System Compatibility
This controller is designed for cooling and refrigeration control. It turns the cooling output on when the detected temperature rises above the set control range, and turns the cooling output off when the target temperature is reached.
Typical use cases include:
12V DC compressor cooling systems
Low-voltage refrigerator control projects
Small freezer temperature control
Portable cooling system upgrades
Cooling cabinets with defrost needs
Defrost Compatibility
The STC-201 includes a separate defrost output for systems that require defrost control. It supports both automatic defrost cycles and manual defrost operation.
Automatic defrost can be set by cycle interval and duration. Manual defrost can be used when frost or ice buildup appears before the next automatic cycle, or when maintenance and troubleshooting are needed.
Please Check Before Use
This product may not be suitable for:
AC-powered systems
Systems requiring medical-grade temperature compliance
Life-support or critical storage applications
Loads that exceed the relay capacity
Installations without proper fuse, circuit protection, or wiring safety
High-humidity, corrosive, or strong electromagnetic interference environments
If you are not sure whether this controller is suitable for your system, please send your power supply, load type, wiring plan, and application details to yelodeer@yelodeer.com before ordering.
Specifications & Sizing
Key Specifications
Product Type: 12V DC microcomputer temperature controller
Model: STC-201
Power Supply: 12V DC
Sensor Type: NTC sensor
Temperature Display Range: -50°C to 120°C / -58°F to 248°F
Temperature Control Range: -40°C to 20°C / -40°F to 68°F
Operating Ambient Temperature: -10°C to 60°C / 14°F to 140°F
Working Humidity: ≤80% RH, non-condensing
Compressor Output Relay Rating: 30A, resistive load
Defrost Output Relay Rating: 10A, resistive load
Default Temperature Unit: °F
Temperature Unit Switching: °C / °F adjustable
Main Functions: Cooling control, compressor delay, automatic defrost, manual defrost, high/low temperature alarm, temperature calibration, key lock
Important Load Note
The 30A compressor output and 10A defrost output ratings refer to relay contact ratings under resistive load conditions.
If connecting inductive loads such as compressors, motors, or fans, the actual allowable working current may be lower. Always confirm the load specifications before installation and use proper circuit protection.
Key Adjustable Functions
Temperature Differential (F1): Adjusts the gap between cooling start and stop temperatures to balance temperature stability and compressor cycling.
Compressor Delay (F4): Adds a restart delay to help protect the compressor from rapid cycling.
Temperature Calibration (F5): Fine-tunes the displayed temperature for improved accuracy.
Automatic Defrost (F6–F7): Sets the defrost interval and defrost duration for systems that require frost management.
High / Low Temperature Alarms (F9–F12): Provides adjustable alarm settings to notify users when temperatures move outside the desired range.
°C / °F Switching (F13): Allows the display to be shown in either Celsius or Fahrenheit.
Important Unit Note: Temperature values are not automatically converted when switching between °C and °F. After changing the temperature unit, verify and adjust your temperature settings if needed.
Installation & Accessories
Quick Installation Notes
Before ordering, please confirm:
• Your system uses 12V DC power only
• Your cooling system requires compressor control and optional defrost control
• Your connected load does not exceed the relay capacity
• You have basic DC wiring knowledge or access to a qualified installer
Important:
• Do NOT connect this controller to AC power
• Disconnect power before wiring
• Use proper fuse and circuit protection for your system
Sensor Placement Tips
For accurate temperature control:
• Place the sensor inside the refrigerated area you want to monitor
• Keep it away from fans, vents, heaters, compressors, or evaporators
• Avoid mounting near doors or frequently opened areas
• Secure the sensor so it cannot move during operation
Proper sensor placement helps improve temperature accuracy and reduces unnecessary compressor cycling.
Basic Operation
Set Temperature
- Press SET
- Use ▲ or ▼ to adjust the target temperature
- Save and exit
Defrost Control
• Automatic defrost can be scheduled using the controller settings
• Manual defrost can be activated when frost buildup occurs before the next scheduled cycle
FAQ & Resources
Frequently Asked Questions
1. Is this controller for cooling or heating?
This model is designed for refrigeration and cooling applications only.
2. Can I use it with AC power?
No. This controller works with 12V DC power only.
3. Does it support automatic defrost?
Yes. It supports both automatic defrost and manual defrost functions.
4. Can I switch between Fahrenheit and Celsius?
Yes. The display can be switched between °F and °C.
5. What applications is it suitable for?
Common applications include:
• RV refrigerators
• Camper refrigeration systems
• Small freezers
• Beverage coolers
• Portable cooling boxes
• Display refrigerators
• DIY 12V DC refrigeration projects
6. What should I check before purchasing?
Please confirm:
• Your power supply is 12V DC
• Your load is compatible with the relay output
• The controller's temperature range meets your application requirements
• You need cooling control rather than heating control
