Sunforce 120-LED 1100-Lumen Solar Motion Light

If this thing is solar powered, why does it run off of 3 -AA batteries?

Rechargeable batteries.

Includes: 120 LED motion light, Solar panel with 15 ft. (4.5m) of wire,3 x AA rechargeable batteries and Mounting hardware

They are rechargeable. Charges during the day, supply power at night.