NRF52840 Thread example power down 10 mins after USB disconnect

[meetandyhere]

Hello,

I am trying the Thread Cloud COAP Client

<InstallFolder>\examples\thread\experimental\cloud_coap_client

on a NRF52840 PDK. I'm using Thread SDK v0.10.0. The example works as described.

However, when I unplug the board from USB, it goes into some kind of power down mode in approx. 10 minutes and loses connection to the Thread network. I can see LED1 is still on, but it is extremely faint. It is flickering, so trying to connect to the network, but it cannot do so. After a further 5-6 minutes of this, LED1 goes completely off.

I had a few questions about this behaviour:

1. Where in the code can I set the time between USB disconnect and going in power-down mode?
2. I know that the NRF52840 has System ON and System OFF power modes. Where in the code can I set which mode it should go in?
3. Is the behaviour of it not being able to connect to the Thread network when in low power mode expected? If so, can I change this behaviour or is there a fix planned?

Thanks in advance!

Regards

Andy

[meetandyhere]

The board is powered by a CR2032 battery that came when we purchased the kit. It doesn't seem a battery issue because the board is powered on and works well for about 10 mins after USB disconnect. After a subsequent USB connect and disconnect, we get the same behavior. So there seems to be some pattern with the 10 min power down behavior. Also, non-Thread BLE examples, e.g. HRM from the SDK v. 13.1 run for much longer than 10 mins on battery. So I was wondering if it is some Thread-specific issue?