7AH Batteries for Gate Opener 2 (Two) pcs. The greater capacity of the batteries, the longer the system will operate in cloudy days. The solar energy conversion efficiency may vary with installation places and weather conditions. Install the solar panel in open area clear of obstructions such as tall trees and buildings which probably block the sunlight. The solar panel should be installed with its surface facing with the most sunshine, south-facing in northern hemisphere and north-facing in southern hemisphere.