5000mAh cells are dirt cheap nowadays so when you pay ~$1,50 for one, double that and it’s $3 each, $1,50 increase. TS26 going from $43 to $44,50 is not a big deal.
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Great logic, but mister typical bargain hunting person who has no clue will care when he sees the prices listed somewhere online.
I understand your motivation, I have way to many cells. Many I purchased simply because they had slightly more capacity than the multitude of others I already have. Know lots of others that would snap up the $2 cheaper light every time.
TS28 5000K was meant to come out yesterday. Something must have went horribly wrong that it was postponed for 8 MONTHS!
that was my question, I couldn’t find it in the datasheet.
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Maybe they got it as a special order? Like SFT-60 was designed for Acebeam or something like that.
Unfortunately, during the testing process, we found issues of this new LED with multiple fogging and smoking. We had to find the supplier to solve the problem and postpone its launch
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Smoking? Are you sure that’s LED/supplier issue because SFT-70 is known to handle much higher current (8A) than in the TS28 (6A).
SFT-70X-W High CRI have the 4A max current, apparently:
Source: https://download.luminus.com/datasheets/Luminus_SFT-70X-W_High%20CRI_Datasheet.pdf
(5000K variant is not mentioned there, btw).
Theoretically yes but people were running even the less efficient 3000K variant even with 8A driver.
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I Run a 3000K version in my TS28… so far no problem.
Are You sure the 3000K is less efficient? and therefore more of a problem? are you implying there is gong to be significantly more heat from the 3000K version then from the 5000k version?
3000K from comes in G1 flux bin, the newer generation is slightly better at G3 or G4. Higher CCTs at lower CRI (90 instead of 95) come at G5 or G6, maybe Wurkkos got a custom one at 5000K and high flux because 2700lm out of the front at 6A is no slouch. Definitely way more efficient than the old 3000K producing just 2000lm at 6A (minus optical losses we’re talkign abotut ~1800lm otf).
I think the lower Lumens with with lower cct and cri correlational not necessarily comes from the LED beeing less “efficient” but from humans eyes haven lower Efficacy for Light with “less green”.
But on the other hand there are not many High densely and High CRI LEDs so maybe the “better” phosphor is not as Stable for high flux Density.
Lumens have nothing to do with human eyes, it’s a measureable unit and in combination with power draw we can judge efficiency. Less efficient=more heat=more difficult to drive hard in the same package. That’s why less efficient variants of this LED have lower max recommended current. But overdriving exists, SFT-70 is known to take much higher currents without issues that’s why I’m surprised Wurkkos had issues at 6A with more efficient (=cooler) variant than good old 3000K G1.
You are wrong there.
Lumen is perceived power not actual power
The luminous flux accounts for the sensitivity of the eye by weighting the power at each wavelength with the luminosity function, which represents the eye’s response to different wavelengths. The luminous flux is a weighted sum of the power at all wavelengths in the visible band. Light outside the visible band does not contribute. The ratio of the total luminous flux to the radiant flux is called the luminous efficacy. This model of the human visual brightness perception, is standardized by the CIE and ISO.[7]
This is the Difference between photometric and radiometric units.
You can have a green LED With WAY more Lumens compared to a red LED at the same input power,
But the red LED can still be way more efficient and therefore give out less heat.
There are many very efficient red 660nm leds. human eyes just have low luminous efficacy at 660nm therefor the lumen rating is low. nevertheless the led is Efficient in converting electrical power to 660nm Photons and (and therefore less of it to heat)
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As a general rule, lower CCT LEDs produce fewer lumens at the same power, or use more power (and make more heat) for the same lumens, and LED product binning from every manufacturer reflects this. Take a look through data sheets from Cree, Nichia, or other manufacturers to see the actual numbers and product SKUs, but in general, every 1000-2000 Kelvin difference comes with a higher or lower rated bin, and the bins are typically about a 7% difference in efficiency and maximum brightness.
In my experience doing thermal testing, cool white LEDs perform much better than warm white LEDs. They make more lumens and less heat, so turbo lasts longer and they settle at higher brightness levels, and the warm white LEDs are much more prone to rapid aging when driven hard.
A similar effect is common as CRI gets higher. The LEDs get less efficient and run hotter and don’t make as much light.
For an analog in a different field, the same thing happens with audio. A “tweeter” speaker can be very loud without using much power, because it vibrates quickly with a small amplitude. Meanwhile, a “woofer” speaker uses a lot more power in order to achieve the same loudness, because it needs a much higher amplitude to compensate for the lower frequency.
With LEDs, red (or “warm” light) is the “woofer” and blue (or “cool” light) is the “tweeter”. But the effect isn’t as pronounced as it is with audio, because audio covers ~10 octaves, while visible light only spans a single octave. Instead of a 10x power difference, it’s generally under 2x.
On a related note*, that’s also probably why violet looks like red+blue (i.e. purple). The longest visible wavelength (red) is nearly 2x as long as the shortest visible wavelength (violet), so violet resonates with the eye’s red receptors. The blue receptors are activated at short wavelengths, but the harmonic resonance of the octave spacing also causes the red receptors to activate a bit, which makes violet light appear purple. It’s like having 2 guitar strings next to each other, an octave apart. Pluck one, and the other will typically start to wiggle a bit with sympathetic vibrations. Without that effect, violet light would just look really, really, deep blue.
* Hah, get it? I’ll see myself out.
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Sure of course. But this is even true if the LEDs have the same output flux in mW of light.
Assume we have a 2700K high CRI, a 5500K low CRI LED, and a green LED. If they all have 3W input power and 1000mW optical output power, the lower cct 2700K high CRI would output significantly less lumens, about 100 lumens.
The low CRI 5500K LED will have maybe about 200-300 lumens.
And the green LED is 600 lumens.
They all need 3W, they are all 33% efficient, and they all make 2W of heat.
In this scenario, of course, if you compare lumens by lumens, the low CCT LED would need 2-3 times more power to get the same lumen output and therefore make 2-3 times more heat.
But in this example, this is only a function of human vision and the lumen curve, not on the efficiency of the LED.
@QReciprocity42 can clearly explain this better, but in short efficacy ≠ efficiency
At a lower CCT, the same optical power is perceived less brightly by the human eye (so the lumens are lower), even if the true physical optical flux is the same.
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How far do you expect it to be postponed? Current date stated on the product page is April 8th, hopefully not 8 months and that’s just a placeholder?
3000K is less efficient than 5000K because, in order to achieve a lower color temperature, it needs a thicker phosphor layer. As a result, more energy is converted into heat.
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Maybe. but what data do we have to back up this hypothesis?