@teastain2 Thanks Terry,
I checked the switch and power key, It doesn't work
The modem SIM7080G is still not powered on and the voltage for the SIM7080G remains 0.9V
Therefore I checked the PMU and I found the root cause.
The PMU initial is always failed when using the USB charger or the battery, And it will stuck at the while 1 loop
Just modify the initial procedure and remove the while 1 loop. And then the modem starts working !!

Hi,

I have tried the example "ModemMqttPulishExample"
I modify the APN, deviceID, Server IP, and some keys for the MQTT server,
Everything is working fine with PC / MAC, The data upload to the MQTT server perfectly.
But these only happen when connected to a PC / MAC
When I unplug the USB cable and plug it into a USB Charger
The board doesn't work anymore. Even I push the PWR key (1 ~ 3 sec.). The board still not running.
And then, I try to use the battery (18650) to power the board ( Switch On and press the PWR key for 3 sec. ). It still doesn't work.

I have tried three different types of USB chargers (USB Type A, Type C) and a power bank.
I checked some voltage ( VSYS = 5V, PMU_DCDC3 = 0.9V )
It seems the ESP32-S3 doesn't run when using the USB charger and the battery.

Any suggestions?

Thanks