There are a number of factors which can significantly affect the battery life of the sensor including; transmission period, WiFi encryption method, WiFi encryption key rotation frequency (determined by the Access Point or router), signal strength between access point or router and sensor device, presence volume and type of WiFi traffic from other devices, sample rate, and operating temperature.  In our tests, we regularly achieve battery life in excess of six months with a transmission rate of one hour or more.

Below is a brief matrix of estimated battery life for a number of WiFi transmission period scenarios: