Luminus SST-40, a N4 BA bin tested

[Lightbringer]

Huh… just thought of something.

LEDs, whether warm or cool, have a weak spot in the bluegreen area of the spectrum. There’s not enough difference in wavelength to reradiate bluegreen from a blue light. Just like new LEDs use violet LEDs to excite phosphors for better “blue-end” response, maybe the shift towards “bluer” with high currents creates less “green tint” (not sure where exactly in the spectrum this’d be, more like yellow-green from what I recall).

It was… maukkona(?sp)… who did the spectral stuff with LEDs. Anyone want to engage him to do that for the same LED but different drive levels?

[Agro]

@LightRider

Fet only driver uses pwm only to dim the led. When using fet and pwm the led sees the same max current on all levels just for shorter periods of time. Cc drivers reduce the current and show it to the leds constantly.

Not really. It was measured in the D4 thread that with fast PWM current is always in some intermediate state.

[Sledgestone]

@LightRider

Fet only driver uses pwm only to dim the led. When using fet and pwm the led sees the same max current on all levels just for shorter periods of time. Cc drivers reduce the current and show it to the leds constantly. An led generally shows more color warms up a bit at lower currents as aposed to higher currents where the led shows less color and becomes cooler k wise. Usually increasing the current to the led will continue to get cooler till the point when it starts turning blue and then poof.

So in the case of the traveling green curse above there are two scenarios :
1.) the led is getting less current and showing more green color,
2.) the led is overdriven and turning green.

If the driver is causing the trouble it would have to be because if scenario two. As it is an fet only driver and show max current to the led at all times. Even so leds usually turn blue when over driven not green. However thus led shows a “new” tint that is generally unfamiliar. Does anyone know if overpowering an sst40 turns the tint to green?

Very weird to see such a difference! If there is some other aspect of this driver, other than the curse, that would open up some new parameters in the search for good tints:)

How many amps are you referring to when you’re talking about overpowering the LED? With the FET+7135 the lowest modes shows very green tint, but the two highest shows none. This driver draws 8.6A on turbo and the tint is perfect white. So at that amperage it doesn’t turn the sst-40 green.

[Jerommel]

@Agro

@LightRider

Fet only driver uses pwm only to dim the led. When using fet and pwm the led sees the same max current on all levels just for shorter periods of time. Cc drivers reduce the current and show it to the leds constantly.

Not really. It was measured in the D4 thread that with fast PWM current is always in some intermediate state.

That would be the case when the PWM frequency is somewhere up in the MHz range, which is probably not the case in the D4 driver.
You would need a serious HF FET for that too, or it will get hot.
I guess it must be the current meter that smooths things out.
(but i haven’t seen the post you’re referring to)

[Agro]

@Jerommel

@Agro

@LightRider

Fet only driver uses pwm only to dim the led. When using fet and pwm the led sees the same max current on all levels just for shorter periods of time. Cc drivers reduce the current and show it to the leds constantly.

Not really. It was measured in the D4 thread that with fast PWM current is always in some intermediate state.

That would be the case when the PWM frequency is somewhere up in the MHz range, which is probably not the case in the D4 driver.
You would need a serious HF FET for that too, or it will get hot.
I guess it must be the current meter that smooths things out.
(but i haven’t seen the post you’re referring to)

TK's Emisar D4 review

Perhaps in the future it can do that. IIRC, Tom’s NarsilM already does it… but this was kind of forked from an earlier Narsil and simplified. Thanks! It seems CRI is not completely straightforward, but the cooler-when-brighter trend appears to be fairly consistent at least. Yes, 7135 chips do not attempt to convert extra voltage into current. They burn off the extra voltage instead. Same with a FET. A voltage-converting driver should be more efficient when the battery is full and emitter Vf…

[Jerommel]

Thanks.

[Sirius9]

So, about Toluene.
Want to get some so I give it a look and guess what, there is a local company making this stuff, I was excited, could it be, source in my own town! Picked up the phone, give them a call, yes they produce it, yes they sale it but I can’t buy it because they don’t have retail store, and they don’t want to give me info which company buys from them and has retail store so I could contact them.
Bloody bureaucracy :rage:

[EagleShield]

What is the best forward voltage bin for this led for flashlights with the A17DD or X5/X6-driver?

Forward voltage bins for sst-40

As giorgoskok wrote, the sst-40 specs from aliexpress store: Shenzhen Great Technology Co.,Ltd.

Flux : N4
Color : BA
Voltage: VK (min: 2.9V max: 3.1V)

You see that there are 2 bins lower then the VK bin and I guess if you use those with DD-FET driver you get more Amps (if I understand this correctly) then the VK bin but that means more heat.
Are those VH and VJ bins better (more Amps = more light) or are they so good they get worse (to much amps = to much heat and the led burns)?

Edit: removed a picture as requested (couldn’t they just go to Kaidomain’s site and copy that picture instead?)
.

[EagleShield]

I see that Kaidomain’s Sst-40 have the VJ bin (Min: 2.7V Max: 2.9V).

Anyone who have both the aliexpress sst-40 (VK bin) and the Kaidomain’s sst-40 (VJ bin) that have made a comparison?

.

[giorgoskok]

It would be better not to post the pic of the reel here EagleShield !

Thanks

[Agro]

@giorgoskok

It would be better not to post the pic of the reel here EagleShield !

Thanks

Why?

[giorgoskok]

@Agro

@giorgoskok

It would be better not to post the pic of the reel here EagleShield !

Thanks

Why?

In the past sellers have goten pics etc from forums (+ it appears in google pictures) etc selling fake leds and more.

[Agro]

OK…

[giorgoskok]

@Agro

OK…

At least happened to me once from ebay seller :money_mouth_face:

[EagleShield]

@giorgoskok

It would be better not to post the pic of the reel here EagleShield !

Thanks

Removed it

.

[Agro]

The SST-40s from Aliexpress come on PCBs.
Are those PCBs total junk, just bad or mediocre?

[Sledgestone]

Got a link?

[Agro]

https://www.aliexpress.com/item/10PCS-Luminus-SST-40-10W-LED-1100lm-Cool-White-7000K-instead-of-CREE-XML2-XM-L2/32804792539.html

[Sledgestone]

Yeah, those are crap. No copper, just aluminum. Get yourself some noctigons from hank! :+1:

[Agro]

Aluminum isn’t a top performer, but isn’t bad either. If these are DTP, they should be passable for cheap lights….and Kaidomain PCB + LED costs about the same as Aliexpress LED (when buying 10) + Noctigon. Similar DTP, but Aliexpress diodes are factory rejects of random bin and with KD one knows what they buy. There is an intermediate option of using KD PCBs ($1.5/piece) with Aliexpress emitters though.