Hi i am using ble_app_uart example in sdk 15.3.0 as far everything is fine even i added a app_timer for about 20 sec to advertise again but the problem is when i power up using coin cell or li-po battery the device struct, it's not running and i don't know what is happening. How i conformed that it was struct by the help of led4 in the board, which i set in the main function starting and after delay i cleared but still led was on and no advertising when it in external supply. i don't think there is any issue with app_timer but other than something could be added or removed in the config file. device works fine if connect usb.
This is very similar to your last post. Seeing as the cases are likely correlated I will close this one, and we can continue this in your other post.