A lighting device is mounted onto a support structure, e.g., helmet. The lighting device includes a light body having forward facing light sources including a visible white light source, visible colored light source, an infrared light source and a side facing IFF light source. The light body includes switches for activating the visible light sources and a three-position switch for activating the IR and light sources. The light body mounts onto a mount assembly and includes a connector arrangement for slidably connecting to a platform of the mount assembly. A base member of the mount assembly includes a clamp that connects to a support structure. The light body and platform member may be swivelly moved relative to the base member by forcing the light body and platform member away from the base member and rotating the same. Also disclosed is boost circuitry, battery chemistry detection and control modes.