Right now they will charge inside the unit, that's not saying that we can't easily build an external charger. With a 4 hour battery life, do you think it's really necessary? Any feedback is appreciated. Yes, the user glass is replaceable. Actually the whole unit comes apart for ease of cleaning. My apologies for the answer you received from our customer service department. She's pretty much focused on DaVinci right now and doesn't have in depth knowledge on specs of the new unit.