How to Use The MAX17201/MAX17211 and MAX17205/MAX17215 to Fuel-Gauge Primary Cell Batteries

By: Hushnak Singh

Abstract: Primary cells pose a special challenge to fuel gauges. They are used in applications very sensitive to current consumption. Typical applications include smart sensors, smart meters, fire alarms, and other IoT devices that must operate for multiple months or even years without charging or changing batteries. Fuel gauges in these applications must not become a dominant source of power consumption. The nonrechargeable nature of the cells means the fuel gauge never has a chance to learn the capacity of the battery, and must achieve the accuracy through techniques such as accurate coulomb counting instead. For some chemistries, a flat voltage curve also means a direct voltage lookup method is not usable.