I just recently had this happen to me and I did get locked out when the battery in the lock died. It happened at 11 at night when I came back from a long trip and my landlord was not responding to calls. After about 10 minutes of Googling I figured out that there are 2 prongs at the bottom of the lock that you can connect a 9-volt battery to to give the lock temporary source of power. I went out and got a 9v battery and unlocked the door with my fob while holding the battery terminals on the 2 prongs.