Heat shrink is a good idea. I wrap the ends with orange electrical tape. Makes for a softer bite pad. Haha. Also the orange won't leave the black tape marks on your lips. As it comes loose you tear off an inch or so and your good again. If I know I'm gonna need a light for an extended amount of time I use my headlight. A streamlight Argo works great.

When every circuit board is made. They put a little magic smoke inside.