2025-11-19
- Type: multi die, 64 chip
- Bin: —
- Color group: 6500 K
- CRI: 70
If you’ve been wondering whether there’s anything more powerful than the SFH55… here you go.
The LED tested here was provided to me by BLF user @billy_s. Many thanks for that!
The SFY55 is an extremely large LED. With a total size of 16 x 16 mm (sometimes referred to as “160160” or “XHP160”) and a light-emitting area of over 100 mm², it seems almost ridiculously large, especially when compared to other LEDs with a smaller footprint. In contrast, an LHP531 (second image) appears almost tiny. This illustrates just what a monster the SFY55 actually is.
The 64 chips are arranged in an 8x8 grid. All chips are connected in parallel. This should keep the forward voltage low.
As is customary with ChangDa, the LED chips are mounted on a dark gray ceramic substrate. Compared to the SFP55, different LED chips were used here, which are about 20% larger (1.41 x 1.41 mm) and also square. A vias pattern is not visible under the phosphor. These chips may have a different characteristic curve/luminance, so a comparison with other ChangDa LEDs is only possible to a limited extent.
The luminous area is approximately 152 mm2. Light emitted from the sides makes it difficult to measure the LES accurately. Some chips are dimmer than others, which indicates relatively wide flux/power binning on the part of the chip supplier.
- Maximum reached at 60 A, at this point 23402 lm @ 2.96 V
- Power at maximum 178 W
- Efficiency at maximum 131.6 lm/W
Data for 25 °C Tsp (at 85 °C the luminance values are around 13 % lower).
The power supply with a maximum of 60 A was maxed out. According to the luminous flux curve, the maximum should be 80-100 A and well over 30,000 lumens. These are extremely high values for a single LED, which are only surpassed by huge – and far more expensive – COBs.
The parallel connection of all 64 chips results in very high efficacy, since every single chip in this array is driven with very low current and has very low Vf. The power reserves beyond 60 A are evident in the 131.6 lm/W. The Vf in general is extremely low, although at 60 A each chip is supplied with only 938 mA, which puts the low Vf into perspective.
The luminance is very low. Due to the light emitted from the sides of the chips, the very high number of LED chips, and the associated low maximum current per chip, this is less than 60 cd/mm2 at 60 A. These values appear extremely low; however, measurement errors could be ruled out by an additional calculation of the luminance. Even at maximum luminous flux, more than 85 cd/mm2 is not to be expected.
This is one of the problems with LEDs with a large number of individual chips: the operating current of each chip is very low, but a high luminous density requires a high operating current per chip, even with very small LED chips.
The tint is greenish and lies outside the ANSI color space. There are no surprises in the spectrum; as expected, the color rendering index is in the Ra 70 range. As usual, classic YAG:Ce3+ phosphor is used here.
As is usual with ChangDa, the tint shift is not very pronounced as the operating current increases. The beam is perfectly fine, as far as could be tested in a reflector.
- Ra: 69
- R9: -39
- CCT: 5954 K
- duv: 0.0071
This LED is absurdly large, extremely powerful, and relatively inexpensive at the same time. In addition, the beam is good—as far as it can be tested.
Compared to other popular LEDs, the SFY55 seems like a meme turned into an LED; it simply seems surreal.
If you have a host with a sufficiently large reflector opening and heat dissipation, as well as an extremely powerful 60 A+ driver, this LED is hard to beat, at least as long as the tint is not a major issue and the very low luminance is not a problem.
Thank you for reading this test. 
