In series? Bah. If the goal in having four leds was increased lifetime you've missed out on an opportunity... While I have no doubt that driving them with decreased current will dramatically increase life, you'd get more still by parallel wiring so that one LED could fail open without killing the bunch... then getting the drive voltage you want by some other means (wiring multiple modules in series..)
Though.. I must admit, the series wiring soldering job looks really nice in the picture.
Connecting each in parallel will guarantee premature failure unless each also has its own current limiting resistor.
I've never seen a decent quality LED fail open. I've seen lots of bargain-basement Chinese LEDs fail open, but in each case there were lots of DOA units in the lot and it turns out that you can watch the junction noise and immediately identify which LEDs are going to fail. They show significant junction instability even when brand new. That leads me to the conclusion that the junctions pretty much only fail due to manufacturing defects, and simple testing can weed the defects out.
Ever wonder what the difference was between the US made LEDs that cost $1 apeice and the Chinese ones that cost $.02? Now you have part of the answer :-)
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"Solder the four LEDs in each cube in series"
Date: 2008-05-06 02:37 pm (UTC)Though.. I must admit, the series wiring soldering job looks really nice in the picture.
Re: "Solder the four LEDs in each cube in series"
Date: 2008-05-06 05:12 pm (UTC)I've never seen a decent quality LED fail open. I've seen lots of bargain-basement Chinese LEDs fail open, but in each case there were lots of DOA units in the lot and it turns out that you can watch the junction noise and immediately identify which LEDs are going to fail. They show significant junction instability even when brand new. That leads me to the conclusion that the junctions pretty much only fail due to manufacturing defects, and simple testing can weed the defects out.
Ever wonder what the difference was between the US made LEDs that cost $1 apeice and the Chinese ones that cost $.02? Now you have part of the answer :-)