Iduino Mega R3 not working / GSM module??

[khurram]

I have been told that the gsm module requires almost 2 ampere current when sending text message - can the battery handle this? what would be the backup time with a new battery?

[zhangxueyou]

VRTC connector only power for RTC module, not the whole SIM module. The burst current of SIM is around 2A, so it need external power.
The module can work without battery.