I have an old 3D maglite with an LED upgrade bulb I bought from Walmart that is also a Maglite brand. I was going to change out the bulb for something better since this light is not nearly as powerful as my HD Husky 2D tactical. But then I got to thinking, if it has a long run time it might be good to leave it that way for power outages when I need a really long run time. Anyone know what the run time would be?