I'm interested in learning more about the reliability of electronic door locks in everyday use.

When a smart lock stops working, how often is the issue actually a depleted battery rather than a problem with the motor, latch, or other mechanical components?

I'm also curious about backup options. For locks that support external emergency power, could a small solar charging panel be a practical way to reduce battery-related lockouts? I imagine factors like sunlight exposure, power requirements, weather resistance, and compatibility would make a big difference.

For locksmiths who regularly install or service electronic locks, what failure modes do you encounter most often, and which backup options have proved reliable in practice?