After years of steady usage, my big powerful Fat Max rechargeable flashlight suddenly stopped working. I was bummed because it had been a dependable waterproof tool that had thrown a bright beam of light for a quarter mile or more; just the thing for checking the creek level during storms or to see what was making that noise along the fence-line.
I thought the rechargeable batteries had probably died so I took it apart to see if I could replace them. While taking it apart I accidentally triggered the light. It was still very, very bright. The batteries were obviously not the problem, so I started looking for for the real cause of the problem.