These solar lights are powered by solar energy through the solar panels. The panels convert the sunlight into electrical energy and then charge the Lithium rechargable batteries during the day. A light sensor turns on the light automatically at night. Ideally, the light should be in a place to capture the maximum amount of sunlight. The light source is super-bright LED's which can work up to 10-12 hours at night after a full sunny day of charging. Easy replacement of battery. No wiring required. This product is green and enviorment-friendly.