Power supply Consumer type smart locks don't connect to electricity all the time. It leaves two options of their power source: replaceable batteries – like standard AA type – or a rechargeable accumulator. You need to make sure how long it lasts and adjust it to how often you use the door.

The vast majority of smart locks in 2026 are powered by internal batteries, specifically a set of four AA or AAA alkaline batteries. This battery-powered design is favored because it allows for easy DIY installation without the need for complex electrical wiring through the door frame. Higher-end models may utilize rechargeable lithium-ion battery packs, which tend to last longer in extreme cold and provide six to twelve months of use on a single charge. Beyond standard batteries, some 2026 "Smart City" locks are now using Solar-Power harvesting; these units have a small solar strip on the exterior of the lock that converts ambient sunlight into energy, storing it in an internal buffer to reduce the frequency of battery changes. Another innovative power source is Power over Ethernet (PoE), which is common in commercial buildings where the lock is hardwired into the building's electrical and data grid for 100% reliability. To prevent being locked out when the power source fails, almost all smart locks feature a "low battery" warning system that sends notifications to your phone, and many include an emergency 9V battery jump-start terminal on the bottom of the exterior unit to provide a temporary boost if the main batteries die.