The sensor locker lock is powered by 4pcs AA Batteries, last 5-10 months normally.
If low Voltage (<4.8V), there will be alarm sound to remind you changing battery.
All locks we supply have an external power port on it.
If battery totally exhausted, connect a battery case with 4 pcs AA battery, then unlock.
You don't have to destroy the locker/cabinet if battery dead.
You can also use a transformer to transform your city power (AC) to DC (6V) to supply power to all locks centrally.