Battery life
The sleep currents here were measured on our own boards rather than copied from a datasheet. The gap between the two is usually a factor of ten, and the datasheet figure is the one that sells the wrong cell.
9.5 months
3000 mAh × 0.75 ÷ 0.326 mA average = 9.5 months
Board — sleeps at 0.043 mA, wakes at 85 mA
Wakes every 30 minutes
Average draw
0.326 mA
Duty cycle
0.33%
Sleep's share
13%
The average draw is 0.326 mA, and 87% of it is the 6 s awake — at a wake every 30 minutes the radio dominates, so the win is in joining faster or waking less often rather than in a lower sleep current. Only 75% of the cell is counted: the regulator drops out before the cell is empty, the cold makes that worse, and a coin cell cannot deliver a Wi-Fi transmit current at all without a capacitor across it.