Originally Posted by
cyccommute
Bayonet mount bulbs like the Krypton ones can rattle around in the base. As you ride the light can bounce in and out of the base and lose monetary contact with the battery. It's like turning the light one and off constantly. As others have noted that's when most bulbs burn out.
The MR bases are pins that plug into a socket. They don't bounce around much.
Undervolting halogens is probably worse then overvolting. (Your bulb isn't a halogen.) Halogen needs the temperature to get the cycle going.
Interesting hypothesis. I still don't get though why the Krypton stars died in a few days, while my slightly undervolted Magnum star is alive two years later. Shouldn't they both have the issue with the rattling around the base?
Here's an idea. Could it be that the bulb bases are somehow intentionally built so that any overvolting will burn out some part of it as a safety measure? I can see how the company would rather have people lose a bulb than suffer any explosion.
With regard to undervolting halogens, yes I share your concern with making sure the halogen cycle runs. I know I'm not running a halogen (although seeing how the bulb surface still looks clear, I don't know if the Maglite bulbs have some halogen content or not). I'm thinking how a slight undervolting (say at 95% of rated voltage) can lengthen lamp life tremendously, while probably still having the halogen cycle operate.