The **RTS-3C1-R** is a specific electronic component, typically categorized as a **Remote Temperature Sensor** (specifically associated with solar charge controllers like EPEVER/EPSolar) or a **Resistor/Relay variant** depending on the manufacturer's prefix. In the context of power electronics and solar systems, it is most commonly a **Remote Temperature Sensor**. Below is the breakdown of its electronic characteristics. --- ### ## 1. Technical Specifications The device is designed to measure battery temperature to allow a controller to perform temperature compensation for charging voltages. | Feature | Specification | | :--- | :--- | | **Component Type** | NTC Thermistor (Negative Temperature Coefficient) | | **Resistance Value** | 10kΩ at 25°C | | **Connector Type** | 3.81mm / 2P Plug (or RJ11 depending on version) | | **Cable Length** | Usually 3 meters (R suffix denotes length/revision) | | **Operating Temp Range** | -55°C to +125°C | | **Accuracy** | ±1°C | --- ### ## 2. Internal Electronic Parts The RTS-3C1-R consists of three primary physical and electronic elements: 1. **Thermistor Bead:** * The core sensing element is a high-precision **NTC resistor**. As the temperature rises, the resistance decreases. The charging controller measures this resistance to calculate the battery's ambient heat. 2. **Epoxy Encapsulation:** * The sensor head is encased in a thermally conductive epoxy resin. This protects the delicate semiconductor from battery acid fumes and moisture while ensuring fast thermal response. 3. **Shielded Wiring:** * The "3C" in the part number often refers to the cable construction. It uses high-grade copper wiring with PVC insulation to minimize electrical noise, which is critical since the sensor operates on very low voltage/current signals that could be distorted by nearby solar inverters. --- ### ## 3. Working Principle The electronic circuit operates on a **Voltage Divider** principle inside the main controller: * **Step 1:** The controller sends a small reference voltage ($V_{ref}$) through the RTS-3C1-R. * **Step 2:** The controller measures the voltage drop across the sensor. * **Step 3:** Using the Steinhart-Hart equation (or a lookup table), the microprocessor converts the resistance to a temperature value. * **Step 4:** The controller adjusts the bulk/float charging voltage (e.g., decreasing voltage by 3-5mV/°C per cell) to prevent battery gassing or undercharging. --- ### ## 4. Connection Diagram | Pin | Function | Description | | :--- | :--- | :--- | | **1** | Signal (Temp +) | Connects to the NTC input | | **2** | Ground (GND) | Common return path | | **3** | NC / Shield | Often unused or connected to cable shielding | ---