I have problem with led brightness on 0,1% of power is most visible I have 4 diodes 1 works on 100% 2 on ~95% 3 on ~80% and 4 on ~50%
It’s completely normal micro impedance differences or faulty LEDs?
I have problem with led brightness on 0,1% of power is most visible I have 4 diodes 1 works on 100% 2 on ~95% 3 on ~80% and 4 on ~50%
It’s normal if they are all in parallel. There are tiny differences in the forward voltage of the LEDs.
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I did a power of light test.
3 emitters at 10A are visible dimmer than 4 emitters at 10A.
There could be a slightly difference in optics angle but the main reason was get the most out of S2+
Yes, because of higher efficiency at lower current. Thus three LEDs need more power than four LEDs to achieve the same brightness.
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I think 2,5A per emiter at max is a sweet spot for extreme situations 
0,1% is good for handy operations 1% too 10% starts to be a little to much for close range better as an faster biking
I had the same issue when I reflowed 4 Nichia 219B 2700K LEDs many years ago. They were right next to each other on the LED roll.
It bugged me too much, so I took the 2 that had the same output (on the right side) and put in 2 new 219B 3000K LEDs. It made another great 219B flashlight.
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That’s greate idea I want to take SST20 95+ CRI a proper memorial with new build with mixed temperature.
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Great idea! SST20 4000K now has an upgraded phosphor mixture for even higher CRI (should be 98+ typical, by visual comparison to my other high CRI lights), and Convoy’s current batch appears to be the neutral FD2 bin rather than the listed green FB4. They have overtaken 519A as my favorite high CRI emitter above 3000K.
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Whoops! I did a test with triple optics sst20 4000K quad sst20 3000K and single emiter 519A 4000K DD frosted 30° TIR.
Guess what 
What happened?
Beam of single optics are perfect compared to triple and quad.
Triple have artifacts in a beam but quad is quite a mess, acceptable only for outdoors distant objects because every time I use it indoors I have so much artifacts I can’t accept.
DeDome change DUV to rossy that is more pleasing for eyes and no matter how I want to use more neutral sst20 at DUV near 0, 519 DD with -6 steal the show. 3000K. There is something strange in SST because i have more accurate color rendering in theory but for me colors looks better and most natural witch Nichia.
Like sst20 both 4000 and 3000 compared to ~3600K of DD 519A looks unnatural especially very creamy colored 3000K act like filter.
Maybe those newest SST20 CRI97+ will be better?
Could you link which TIR you used? I’m very interested!
If you prefer a rosy tint, stay with 519A. The SST20 is objectively more accurate, but objective accuracy is under no obligation to be subjectively pleasant, and 4000K is an awkward CCT where perfectly neutral can look green.
When did you get your SST20’s? The new SST20’s have higher CRI than the old, but the tint is largely unchanged within any given tint bin.
My lens used is from Convoy I’m not sure I can link model 30° frosted 20mm it’s started to work with me after de dome before was not the best.
I have all my SST20 4000K and 3000K from KD.
I bought them 2 years ago and some of them this month. They can a little different in DUV but it’s not night to day difference.
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Thanks for the info! I’ve always found Convoy’s 3535 single optics to impart a weird tint to the light; on the other hand, Convoy’s 5050 narrow angle optics are perfect to me.
I see about the SST20 coming from KD, I don’t know if they have the updated phosphor or not, especially those from 2 years ago.
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There is also difference between various LEDs too because I bought 20 LEDs 2 years ago and a DUV shift was notable in direct comparison 
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