nRF52 battery consumption estimate

[Mufasa1]

Hi guys, I am trying how figure out the the devzone.nordicsemi.com/.../ works or ecuations to estimate the battery life using a central module.

My central device is battery powered and it goes from deep sleep to active each 10mins transmitting a Write to a peripher 20bytes and an indicate to the central 12bytes size. The connection time is about 50ms and the peripheral advertising interval is 20ms.

I am trying to calculate it in the following way:

RF transmitting = 8.1mA RF listening = 6mA

A average RF transmitting/reciving is 7mA per sec using DCDC enabled Sleep mode is 4uA per sec

estimate RF activity = ( 7mA x 0.05s)

Estimate Sleep mode consuption = 4uA x 3600s x 10s)

Estimate consumption = Estimate RF activity + Estimage Sleep mode consumption

Estimate Battery life = battert capacity / estimate cosumption

Is iit a correct way to estimate the battery life?

Thanks.

[Hung Bui]

Hi Mufasa,

Please correct me if I'm wrong. You are trying to measure current consumption for the central, not the peripheral ?

Do you have your peripheral advertising all the time? I have to ask because we need to estimate the time it take for the central to scan and connect to the peripheral.

You have the connection time of 50ms, but we don't know how long would it take to do scanning before the connection.

My suggestion for the calculation is:

Average current consumption = Estimate RF activity in connection (use the online tool for it) *50ms + Estimate RF activity for scanning (7mA) * the time estimated to scan and establish connection + Deep sleep current * 10minute - (50ms + scanning time) / 10 minutes

Note that, to be on the safe side, you should calculate with 70% of battery capacity as most of the time the listed capacity is only for optimized condition.