No, you will not have to set up the lock again after changing or charging the battery.
You simply place the battery back in the lock and slide the cover back on then using the thumb turn extend and retract the deadbolt one time to reestablish connection with the cloud.
If after about 1 minute the lock does not show online, try extending and retracting the deadbolt again.
If after a few minutes, the lock still does not show online, please open a support ticket here and our Array Care Team will help you.