Unlock Smart Locks When Batteries Die

Method 1｜Backup Mechanical Key (Preferred and Most Reliable)

Most smart door locks come with 2–5 backup mechanical keys, and they are used in the same way as regular door locks: insert into the keyhole, turn to unlock.

Method 2｜Temporary Power Supply with External Charger (USB-C/Micro-B)

Many models are equipped with a USB-C or Micro-B emergency power interface on the outer panel. Temporary power supply is only to wake up the panel, not to fully charge it; if you don't have a power bank on hand, you can rent a mobile charger at a nearby convenience store for immediate emergency use.

Connect the power bank to the door lock → after the panel lights up, use the original unlocking method (password/fingerprint/card) to open the door → once inside, replace the batteries immediately.

Method 3｜9V Square Battery Emergency Contact

Many door locks have a 9V battery contact (two metal contacts) reserved on the outside panel.

Place the connector of a 9V alkaline battery against the contacts → the panel activates → use the original unlocking method to open the door → replace the main battery.

Method 4｜Professional Locksmith／Manufacturer Support

If there is no key, the interface is damaged, or the above methods are ineffective, contact a licensed locksmith or original manufacturer customer service.

The most reliable door-opening solution is still the backup mechanical key; USB temporary power supply and 9V contact points are expedient measures to quickly "wake up" the panel. Keep the backup key properly stored externally, replace the batteries promptly during low-power warnings, balancing convenience and home security.