CAPT OF LTT ACR ACFT OPERATED ACFT WITHOUT REQUIRED EQUIP.

Narrative

OUR ACFT ARRIVED AT THE GATE 45 MINS AFTER DEP TIME. THIS WAS A MORNING ORIGINATING FLT FROM A MAINT BASE. DUE TO PAX CONNECTIONS IN BWI; STATION PERSONNEL WERE SOMEWHAT PUSHY TO DEPART ASAP. WE (MYSELF AND FO) CONDUCTED OUR COMPANY ORIGINATING CHKLIST FOR ACCEPTANCE OF THE ACFT. WHILE DOING THIS LIST; THERE WERE MANY INTERRUPTIONS. SOME BEING: NO ACFT LOGBOOK (STILL AT MAINT HANGAR); COWLING FASTENER ON ENG NEEDING SECURED; AND STATION PERSONNEL CHKING ON WT RESTRICTIONS AT TIME OF BOARDING. I NEGLECTED TO CHK TAIL BATTERY VOLTAGE (AS OUTLINE ON CHKLIST). THE ACFT WAS ON EXTERNAL PWR SUPPLY; WHICH CAUSES TAIL BATTERY VOLTS TO READ 0 NORMALLY. I WOULD HAVE HAD TO SELECT THE INTERCONNECT ON THE ELECTRICAL MASTER TO READ TAIL AND MAIN BATTERY VOLTAGE. THIS I FAILED TO DO. UPON ARRIVING BWI; I NOTICED 0 VOLTS ON TAIL BATTERY. I MADE AN ENTRY IN ACFT LOG AND CALL MAINT. BWI MAINT PERSONNEL FOUND NO BATTERY IN TAIL OF ACFT. THE ACFT WAS FLOWN WITHOUT A TAIL BATTERY. THE BATTERY WAS REPLACED IN BWI (OR INSTALLED) BEFORE ANY MORE FLTS.