Challenges in Measuring Battery Life for IoT Devices and Recommended Instrumentation Techniques

IoT (Internet of Things) devices are presenting new measurement challenges for engineers trying to calculate product battery life because the component current consumption is so tiny.

Rohde & Schwarz application engineer Mike Borsch told Design News that many oscilloscopes in labs lack sufficiently low noise for the required measurements; when measuring micro‑amps or micro‑volts, noise can become a real problem and many ranges are not built for such precision.

This issue is tricky not only for IoT device designers but also for manufacturers of the electronic components used in those devices; developers need accurate characterisation data from component makers (processors, ASICs, Wi‑Fi chips, etc.) to reliably assess battery life.

In recent years, measurement has become more complex because IoT device currents are extremely low. Borsch notes that low‑current and low‑voltage ranges are hard to measure and instrument noise can mask very small signals, making it difficult to determine whether the observed signal is real or just noise.

To achieve accurate assessments, modern instruments must first have low noise, and engineers also need to apply techniques such as averaging, signal conditioning, and filtering; Borsch mentions that “dynamic re‑referencing” can help stabilise signals during measurement.

Borsch recommends that IoT engineers use instruments that integrate multiple functions (e.g., spectrum analysis, power measurement, and oscilloscopy) into a single box, allowing them to view simultaneous events in one place.

He adds that modern measurement ranges must do far more than just measure voltage and time; they must capture current, voltage, and frequency‑domain signal content.

Components may behave differently in isolated lab tests versus when integrated into a full product; the current draw can change once all components are combined.

The biggest concern for IoT products is the sleep state, where measurement challenges are greatest because consumption is extremely low and devices may have many different sleep modes—some IoT devices have up to 15 distinct sleep states, with various components powered on or off depending on the mode.

Ultimately, product and component designers need to understand the tools and instruments available for IoT work and know the best practices for using them; Borsch emphasizes that while many tools exist, proper setup is essential for obtaining the most accurate numbers.