Solar Barn solar lights use stored solar power to illuminate remote areas. 

Each solar light operates as a stand-alone lighting system, it is not dependent on the power generating grid for any power requirements.
The solar lighting unit comprises of a solar panel, re-chargeable lead acid battery for storage of the PV (photo-voltaic) power and one or more LED lights. A solar regulator ensures the battery is charged correctly by the PV module.
The solar lights are controlled by an adjustable timer or a motion sensor or an on/off switch.

Batteries provided with the solar lighting system are a sealed type that require no maintenance and have a life of 5 to 7 years, while the LED lights and solar modules have a service life of 15-20 years.