Weird, those are the exact led’s I have as well. I see you are using the Larger omten switches, so that would explain a little blocked light, but I’m still baffled as to why they seem so inefficient.
I’ve got another red one to build, so I’ll be examining everything very closely to see if there is any difference in output and if so, why. I’m also going to sand the nylon washer thinner to try to minimize it’s effects. Honestly I’m hoping I just screwed something up (although I don’t THINK I did) because it’d be nice to be brighter AND more efficient. The LED that is, although I wouldn’t mind the same thing.
Good luck on that one 
So results for #2 in red are identical to #1. With a 1k limiter and running off my power supply it’s dimmer than the steroid version running a 220 ohm with another 50 in series. I expect they’d be the same with the same limiting resistors.
Well that’s less than ideal. I don’t know what’s going on.
I’m baffled, but now that I think about it the double blue tailcap is pretty dim too (although it’s running a 4.7 or 6.8k limiting resistor). I may bump that to a 220, build a single in blue and a single in red at 2.2k and compare them all.
I can’t fathom why the single might be brighter, but the single I built in green with a 2.2k is BRIGHT.
I’ll be interested to hear what you find.
So far I have done 2 red doubles, 1 red single, 1 green single, and 1 blue double all with the 0805 led’s from lighthouse. On all of them, I have had 560ohm on the driver and 2.2k-6.8k on the tail.
Not something I’d normally consider, but do they carry a low output version of this LED and I just got the wrong one shipped to me?
With the fact that I’m getting a measurement of 5.7mA it’s hard to imagine that they’re having a problem with getting enough power.
No i don’t think they do. I’m more inclined to think we have something stealing current somewhere. Where are you measuring the draw?
I’m putting my DMM in line with the negative battery terminal to brass button and a jumper between the body and tailcap ground.
Keep in mind that driving it from my power supply doesn’t increase brightness, so I don’t think it’s driver related.
I’m staring at your pictures and don’t see anything wrong. I have gotten a board from osh with an internal short one time, but only one out of the batch was like that.
Any way to measure the draw at one of the led’s to confirm how much they’re getting? Is it possible they could have gotten overheated during assembly? (unlikely since we’re talking about 4 different emtters)
Just spit-balling here.
That’s a tall order, but I’m committed to the cause and I have some pretty pointy leads so I think I can make that happen. I’m about to get the boy from school though, so further progress will be on hold till later tonight.
So, when powered from the spring side, dim. Power applied to switch side, bright. I think it’s the damn boards.
Well at least that would explain a lot. Just looking at the boards, are the via’s all present and accounted for?
I think so. Should I try filling them with solder?
I’d check for continuity/shorts first. Its drawing a lot from the battery, so that power has to be going somewhere
Running off of a power supply after filling the vias:
Powered completely by spring side, dim
Negative on spring, positive directly to LED, dim
Positive to outer ring of spring side, negative to LED, BRIGHT!
So a problem between spring pad and back side then.
Nope, even when powering the negative switch contact it’s dim. I’m going to try to jumper from there to the negative pad on the resistor.
Well the negative goes through the resistor, so if you’re connecting power directly to the led- pad, you’re bypassing the resistor.