OpenThread network working on Battery

[ArunRuchir]

I am using OpenThread network and working on CoAP Client and Server examples (Customized). Everything working fine when devices are on main power. 

My client devices are FTD and once I connect them on Battery, they work for some time (1 or 2 hour) and stops communicating. The only thing which works is Hard Power reboot (disconnecting Battery and reconnecting main Power). Upon checking, Battery still has lot of power and there was no sudden or new data flow. Same battery can be again used and again it works for 1-2 hours. 

Unfortuunately, since these are CoAP-Client devices, I am not able to give any command also to them (if some one can suggest). 

Please help.

[Marte Myrvold]

Hi,

Which version of the nRF Connect SDK are you using?

What battery are you using?

Best regards,
Marte

[ArunRuchir]

Hi,

I am using nRF Connect v2.4.1

Battery CR2032

If you look at this image of Battery working, you will see that dip where it gone dead after some time and once main Power is up, battery voltage is still sufficient. 

Kindly help. 

Regards

Arun

[Marte Myrvold]

Hi Arun,

Are these custom devices? If so, have you done a hardware review of the schematics?

It could be that the nRF52840 is experiencing a brownout condition that puts the MCU into a permanent reset state. I have checked internally, and it seems like this is a common issue with CR2032 batteries and nRF52840.

One possible reason is that the CR2032 batteries can typically only supply around 200 µA continuously. Thread transmissions can require much higher pulse currents than what the battery can provide, which causes the voltage to drop during transmission. When the voltage drops too low, the nRF52840 enters a brownout state, which might affect the reset pin functionality, preventing normal recovery.

Adding proper decoupling capacitors (47 µA) might solve the problem.

Best regards,
Marte

[ArunRuchir]

Thank you

I will work on decoupling capacitor and also see if I can use another higher capacity Battery. 

Best Regards

Arun

[Marte Myrvold]

Hi Arun,

Let me know if you still see this issue after making those changes.

Best regards,
Marte