Does BT module updating drain the phone battery?
Update transfer should not have an impact on the battery.
You can always go to System-> Battery and see where the battery is being used most, in 90% of cases the battery drain is caused by the screen.
Decreasing battery percentage WHILE connected to a charger usualy means the charger is an older model, not capable of 1A or more for charging.
Posted in: BlueTooth module & Apps