Please not. I wouldn't want to put my life in the hand of a (hopefully charged) battery. Any failsafe in an elevator must be mechanical and work with total loss

Please not. I wouldn't want to put my life in the hand of a (hopefully charged) battery. Any failsafe in an elevator must be mechanical and work with total loss of power. Anything else would fail at some point. This happens with other product at some points. But elevators are one of the few products trusted by nearly everyone because they never kill anyone.