12V DC Refrigeration Temperature Controller with Auto Defrost & Compressor Delay | YeloDeer

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