Battery-Powered IoT Sensor Draining Too Fast? How I Cut Sleep Current to Microamps
A sensor promised a year on batteries but dies in weeks. The usual causes, and the measure-first process I use to fix battery life.
The problem clients bring: "We promised customers a year of battery life and the units are dying in three weeks." The product is already in the field, and a recall would be painful.
What is really going wrong
- The microcontroller sleeps, but a sensor, LED, regulator or pull-up stays powered.
- Radios wake far more often than the application needs.
- Debug logging and peripherals left enabled in the release build.
- Nobody has measured the actual current profile, so everyone is guessing.
How I solve it
- Measure the real current profile with a power analyser and build a power budget from it.
- Find every leak in sleep: floating pins, always-on parts, regulator quiescent current.
- Restructure the firmware so it wakes, does its work in one burst and goes back to the deepest sleep possible.
- Tune radio intervals to what the product actually needs.
- Recommend small hardware changes, such as a load switch, when firmware alone cannot fix it.
What the client gets
A measured battery-life estimate they can put in front of customers, and firmware that meets it. Often most of the gain comes from configuration, without a board respin.