What happens to smart locks when power goes out?

What happens to smart locks when power goes out is generally nothing bad for basic operation, because smart locks are battery powered and do not rely on household electricity, so they continue to work during power outage. The lock motor runs on 4 AA batteries inside lock, not on AC power, so you can still lock and unlock using keypad, fingerprint, Bluetooth, or physical key even if home power is out. What stops working during power outage is features that depend on WiFi and internet, since your home WiFi router will be down unless it has battery backup, you will not be able to remotely lock or unlock from away, receive notifications, or use voice assistants, and if you have wired doorbell transformer powered chime, that may not ring. If your smart lock uses WiFi bridge plugged into AC outlet, bridge will be down, so remote access via app outside Bluetooth range will fail. However, local access remains, and auto lock still works because it is battery powered. For complete power outage including dead batteries, lock will fail secure, remaining locked, and you need backup key or emergency 9 volt battery power to enter. So smart locks are actually more resilient than traditional electric strikes that fail during power outage.