Need clarity on Battery Life calculations

[beemavishnu]

Hello,

 

I am trying to estimate Battery life. I am using CR2032 with 230 mAH capacity. I am confused with the calculations.

 

As per excels sheet in below link, for 500 ms Connection Interval, average Current consumed is 30.1 µA.

https://devzone.nordicsemi.com/f/nordic-q-a/6746/excel-sheet-for-power-consumption

 

The Connection will be there for 1 day. So my assumptions are,

 

For

500 ms                -->            30.1 µA

1 Second             -->           60.2 µA (30.1 µA * 2)

1 Minute              -->           3.612 mA (60.2 µA * 60 sec) of current is consumed

1 Hour                 -->           216.72 mA (3.612 mA * 60 minutes) of current is consumed

1 Day                   -->           5 A (216.72 mA * 24) of current is consumed

 

With Connection interval of 500ms and if device is in connection state continues for 1Day, whether current consumption is 5A. I am suspecting some basics are mission in my calculation.

 

In few examples its mentioned as (mAH / mA = Hours) to get number of hours. But this is not matching to my assumption.

It may be silly mathematical calculations, but I am trying to get a clear picture with better understanding. Please help me in getting clear picture.

 

Thanks & Regards

Vishnu Beema

[Stian Røed Hafskjold]

Please check out the online power profiler to get the average current for the 52 series: https://devzone.nordicsemi.com/power/ . The excel sheet you linked to is for nRF51, which has a different consumption than the 52 series.

Once you find the average current using the online power profiler, the calculation for battery life is pretty basic, as William E says:

    battery_capacity / average_current = battery_life_time
or:
    mAh / mA = hours

Ampere is not a measure on "amount of current consumed", it's charge per unit time. You can't say that "my device consumed 1 A".
The solution to your calculation in the original post should have a unit of Ah not A, something like this:

    30.1uA * 1 Day = 30.1uA * 24 hours = 722 uAh.