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IoT Battery Life Estimator

Calculate the true lifespan of your deep-sleeping microcontrollers.

Power Profile

mAh

Estimation Results

Estimated Life --
Average Draw --

Energy Consumption Breakdown

Active (0%)
Sleep (0%)
Self-Discharge Warning: Your calculation exceeds 2 years. Most standard Lithium batteries will naturally self-discharge and degrade before reaching this lifespan, regardless of how little power the circuit uses.

About Deep Sleep and Battery Life

The IoT Power Problem

Microcontrollers with radio modules (like the ESP8266 or ESP32 with Wi-Fi) consume a massive amount of power when transmitting data—often between 80mA and 250mA. If left running continuously on a standard 18650 lithium battery, they will die in a matter of days. To run a device for months or years on battery power, you must utilize "Deep Sleep."

How Deep Sleep Works

In Deep Sleep, the microcontroller turns off its CPU, RAM, and Wi-Fi/Bluetooth radios. The only thing left running is a tiny, ultra-low-power timer (the RTC - Real Time Clock) waiting to wake the system back up. During this state, power consumption drops from hundreds of milliamps down to mere microamps (µA).

Why the Math Can Surprise You

Many makers buy expensive, ultra-low-power boards, only to find their battery still dies quickly. The Donut Chart above illustrates why: Your active time dominates your energy usage. If your board takes 10 seconds to connect to Wi-Fi and send a sensor reading, it doesn't matter if your sleep current is 10µA or 100µA—almost 95% of the battery is being burned during those 10 seconds of active Wi-Fi transmission. To improve battery life, focus on optimizing your code to connect and transmit faster!