Re: Cavers - The StenLight, Ultimate 2x3W LED Head
A couple of quick notes from a StenLight designer:
- We shipped the first units to Inner Mountain Outfitters today, they should be in their stock sometime tomorrow.
- The production units have a fairly sturdy bolt-based swivel, not the rivet-based swivel we tried out on some of the prototype units. It weights an extra 5 g but we believe the extra sturdiness and the ability to adjust its tightness (and swap switch handedness) is worth it.
- The production models have one 5 degree lens and one 15 degree lens. It provides a pretty good general-purpose beam pattern, good for caving or outdoor use or bicycling. As PeLu pointed out, separate controls would be complex, not least of which being that we'd need to find a place to put the separate switches.
- Series connection of the LEDs permits significantly higher electrical efficiency and permits current regulation with one circuit. Wouldn't work well with parallel unless you had VERY careful matching; just getting LEDs from the same bin wouldn't be nearly close enough.
- As for redundancy, it is very possible for one LED to fail and the other to keep working when they are in series -- if it fails shorted or the circuit has a short, or even if you put one LED in backwards! The circuit will keep on working and still correctly regulate current to the surviving LED. We have actually tested this scenario. In parallel, if one fails even partially shorted it's totally dead, and if one fails open you send twice the current to the other, perhaps killing it too. So it's not intuitively obvious, but redundancy actually works better in the series connection when you're doing current regulation. Then again Luxeons are pretty darn reliable when you treat them right, and LED failures are probably not the most important thing to worry about.
A couple of quick notes from a StenLight designer:
- We shipped the first units to Inner Mountain Outfitters today, they should be in their stock sometime tomorrow.
- The production units have a fairly sturdy bolt-based swivel, not the rivet-based swivel we tried out on some of the prototype units. It weights an extra 5 g but we believe the extra sturdiness and the ability to adjust its tightness (and swap switch handedness) is worth it.
- The production models have one 5 degree lens and one 15 degree lens. It provides a pretty good general-purpose beam pattern, good for caving or outdoor use or bicycling. As PeLu pointed out, separate controls would be complex, not least of which being that we'd need to find a place to put the separate switches.
- Series connection of the LEDs permits significantly higher electrical efficiency and permits current regulation with one circuit. Wouldn't work well with parallel unless you had VERY careful matching; just getting LEDs from the same bin wouldn't be nearly close enough.
- As for redundancy, it is very possible for one LED to fail and the other to keep working when they are in series -- if it fails shorted or the circuit has a short, or even if you put one LED in backwards! The circuit will keep on working and still correctly regulate current to the surviving LED. We have actually tested this scenario. In parallel, if one fails even partially shorted it's totally dead, and if one fails open you send twice the current to the other, perhaps killing it too. So it's not intuitively obvious, but redundancy actually works better in the series connection when you're doing current regulation. Then again Luxeons are pretty darn reliable when you treat them right, and LED failures are probably not the most important thing to worry about.
