I couldn't find my headlamp while packing for a weekend trip so I went to Wal-Mart and bought another. Same kind as my old one (the $12.77 kind).
It came with batteries and the light seemed very bright.
Before I could pack my new light, I found my old one. It wasn't nearly as bright as my new one. One might assume that the old one needed batteries, but I'm an engineer and I jsut can't help myself sometimes.
I put the new batteries in the old light, and the old batteries in the new light. SURPRISE! Even with the old batteries, the new light was still brighter, though not by quite as much.
Both headlamps look identical, and I doubt much re-engineering goes into a twelve dollar item.
Now I am faced with four possibilities:
1. L.E.D.s grow dim with age
2. L.E.D.s grow dim with use
3. My old light was a production anomaly, and is not as bright as other units
4. My new light is a production anomaly, and is brighter than other units
The last two I tend to discard because of the great difference in brightness. Headlamps are merely LEDs connected to batteries with a switch. The only real variable are the LEDs themselves and I suspect they do not vary that much in production.
Intuitively, I lean toward No. 1, but have no data to back this up.
Anybody know?