Disclosed is a rechargeable battery interconnected smoke detector system of one or more smoke detector(s) wired into a dedicated circuit with a single location housing a DC power backup source, such as a rechargeable DC battery. The DC power backup source may be replaceable or rechargeable with DC current from and AC-DC transformer, a photovoltaic cell, or other means. Electronic relays within the system provide a current to the dedicated circuit by selecting between the line-voltage alternating current source and the DC power backup.