The GardePro SP350 Solar Panel for trail cameras is a great addition to many cameras! The unit is multi-voltage (6, 9 &12) and is compatible with all major trail camera brands.  This unit has its own 5,200 mah battery pack built into the solar panel assembly and allows a camera to draw power from its internal batteries as well as the solar pack.  Most cameras use a comparator circuit that constantly measures the voltage from both sources and draws power from the source with the highest voltage.  Under normal circumstances, the solar pack will serve as the primary source.  However, if there were an extended period of no sunlight or the panel was obstructed by snow, the internal batteries in the camera would take over as a backup until the solar panel was able to charge and regain its primary role.