Patent ID: 8022573

Claim:
A lock mechanism to lock at least one door of a shipping container in a closed position, the lock mechanism comprising: a housing external to the shipping container, the housing enclosing at least a portion of the lock mechanism; and a lock circuit at least partially enclosed within the housing, the lock circuit comprising: a latching mechanism configured to lock and unlock the lock mechanism, a main battery within the housing, a backup battery within the housing, the backup battery configured to provide sufficient power to the latching mechanism to unlock the lock mechanism, a plurality of subsystems; and a lock controller coupled to the main battery and the backup battery and configured to: receive commands related to operation of the lock mechanism, determine a battery level remaining in the main battery, determine if the remaining battery level is below a threshold level, and cause the lock circuit to enter a lower power mode upon determining that the remaining battery level is below the threshold level; wherein: when in the lower power mode, at least a portion of the subsystems, of the lock circuit are not powered, the lock controller receives power from the main battery, and the lock controller monitors an interface to detect a command to unlock the lock mechanism.