Current calculations for NRF9160

[PeterL]

Hi.

I have a Thingy91 that I will use as a remote wake up for another system. I am trying to estimate how long the system will be able to run on a single charge with the 1444mAh battery.

I will be using eDRX with 81.92s cycles drawing 27uA according to the specification. The MCU will be in IDLE mode (2.35 uA) unless data is received from the cloud. 

This equals about 30uA average current for a system that has a maximum wake-up delay of 82 seconds. It sounds almost too low, have I misinterpreted the eDRX current specifications? 

[Stian Røed Hafskjold]

Hi, with 81.92 second eDRX cycle and PTW=0 (Page Time Window length = 1,28, meaning 1x paging cycle during eDRX idle event) the 27uA number is not too far away from what I'm seeing here. What this number does not include is the SIM card current, which is usually significant compared to the nRF91 idle current. The SIM card current varies between manufacturers.

Here are some plots for you. You can see the average current at the bottom of the plot (avg).

81.92 second eDRX cycle, including SIM card:

Idle current, including SIM card:

81.92 second eDRX cycle, excluding SIM card:

Idle current, excluding SIM card:

[PeterL]

That's all I need for now, really helpful! Thank you very much for the answer!