That's why we're glad to see this good idea from Bosch: An elegant, simple work light that mounts to an 18-volt battery. The device locks into the battery in the same way that any power tool would.

Bosch 18V 360⁰ Green-Beam Three-Plane Leveling and Alignment Laser (GLL330-80CG) Power Flexibility: Works with included CORE 18V 4 Ah Battery or 4X C Cell alkaline batteries (sold separately) ...

Bosch Launches 18V Cordless Construction Tools The battery-powered tools facilitate a wide range of construction jobs, including concrete, grinding, drywall sanding, heat, measuring and drilling.