Battery life measurement

[prash4iot]

I have custom board  with nrf 52832. I am using SDK 15.2.0  and softdevice s132 V6.1.0  to transmit advertising packets periodically. I have written simple application that reads battery status and transmitted it in manufacturing data  of advertising packet  To calculate battery life  for custom board I have used advertising interval 20 ms and took readings everyday .  I used CR2032 battery for measurement. With this approach I have got battery life 13 days.  By doing some mathematical calculation  for 1 sec  I got battery life 21 months.   so I am not sure by this approach I get correct battery life for 1 second. kindly suggest remarks on this. These remarks will be valuable for me.

Thanks in Advance.

[Joakim Jakobsen]

Hi. 

I suggest that you take a look at the Online Power Profiler. 

"We in the Nordic Support team have created an online power profiler to estimate the power consumption during a BLE event with different parameters. The profiler gives you information about the different components in a BLE event as well as the average current over a specified interval. All data is based on actual measurements conducted on the nRF52.

The BLE event types you can choose between are advertising mode and peripheral connection mode.
You can also choose different values for the following parameters:

• Voltage (1.7 to 3.6 volt)
• BLE interval (20 to 10240 ms for advertising. 7.5 to 4000 ms for connection)
• TX payload (0 to 31 byte for advertising. 0 to 27 byte for connection)
• TX power (4, 0, -4, -8, -12, -16, -20, -40 dBm)"

Using the power profiler you can input the parameters you have set in your application to see what the expected current consumption will be. 
If or why your application is using too much power is hard to say, because I have no information about your application. 

Best regards, 
Joakim

[prash4iot]

Hi,

Ok.

I am not using dcdc  converter. I want to know that whether above approach is correct or not?  According to you what wiil be the battery life for simple beacon application with 20 ms or 1 sec.?

[Joakim Jakobsen]

I'm sorry but without any more information than that, it is impossible for me to determine the battery life. 

[prash4iot]

Configuration as follows.

Battery : CR2032

BLE Interval : 20ms 0r 1 sec

Tx Payload : 20 bytes

Tx Power = 0 dBm

what will be the battery life I will get for above Configuration?

[Joakim Jakobsen]

Thanks. But I don't have any information about what else your application is doing, or if something else is drawing current. 

I suggest that you enter the parameters above in the Online Power Profiler that I linked to in my previous answer. 
See what the expected current consumption is, and compare it to the current consumption your are seeing on your device. If they don't match, there might be something that is initialized in your application that is drawing power, i.e the ADC or something similar. 

Best regards, 
Joakim

[prash4iot]

By referring above link  I got average current 20 microAmp for following configuration.

Tx Power = 0 dBm

Tx Payload = 27 bytes

BLE Interval = 1000 msec

DCDC = No.

By using 20 microAmp,  I got Battery life approximately 12 months  Also I got  average current on PPK  which are  different from above calculation.. I have captured 2 images with different average current. I am little bit confused which value i will consider for calculation.

a)

b)