The **WSBS-2CA-R/Q** is a high-performance **Battery Sensor Shunt** manufactured by **Vishay Dale**. It is specifically designed to measure high currents in automotive and industrial battery management systems (BMS). --- ### ## Technical Specifications The device is characterized by its extremely low resistance and high power handling capabilities. | Feature | Specification | | :--- | :--- | | **Resistance Range** | Typically 50 $\mu\Omega$ to 250 $\mu\Omega$ | | **Power Rating** | Up to 36 W | | **Tolerance** | $\pm$ 5.0% (Standard) / $\pm$ 1.0% | | **Construction** | Electron-beam welded Power Metal Strip® | | **Material** | Manganin or Ni-Cr alloy resistive element | | **Terminals** | Bolt-connection (Battery Terminal Mount) | --- ### ## Key Features and Construction 1. **Power Metal Strip® Technology:** Vishay uses a solid metal alloy as the resistive element. Unlike film resistors, this provides superior pulse handling and stability under extreme temperature fluctuations. 2. **Low TCR (Temperature Coefficient of Resistance):** The "2CA" series is designed to have a very low TCR (typically < 20 ppm/°C). This ensures that the resistance value remains constant even as the shunt heats up due to high current flow. 3. **Low Thermal EMF:** Minimizing thermal EMF (< 3 $\mu$V/°C) is critical for accuracy in low-voltage drop measurements, preventing "ghost" readings caused by temperature gradients. 4. **Physical Design:** The **"Q"** and **"R"** designations often refer to the specific physical configuration or mounting style (e.g., specific hole sizes or plating types) suited for battery post mounting. --- ### ## Typical Applications The WSBS series is primarily used in environments where precise current sensing is required to calculate **State of Charge (SoC)** and **State of Health (SoH)**. * **Automotive:** Intelligent Battery Sensors (IBS) in Start-Stop systems and Electric Vehicles (EV). * **Industrial:** Large-scale UPS (Uninterruptible Power Supplies) and Solar energy storage banks. * **Heavy Equipment:** Battery monitoring for forklifts and marine applications. --- ### ## Equivalent Circuit Representation When integrated into a circuit, the shunt acts as a precise milliohm resistor: ```cpp // Basic Ohm's Law Calculation for the Shunt Current (I) = Voltage_Drop (V) / Shunt_Resistance (R) // Example: // If R = 100 micro-ohms and measured V = 10mV // I = 0.010 / 0.0001 = 100 Amperes ``` ---