I am one of the many who hates flicker with a passion. You've probably seen tail lamps on newer cars look like flying tiny dots when your eyes scan across even though they look steadily lit when there is no relative motion.
I just came across an LED fixture that has an AC LED module from the flicker hell. It flickers so much that I'm pretty sure this type of LED driver ballast makes the record for the most flickery general service lighting apparatus in the history of electric lighting. Incandescent bulbs have very little flicker and has been regarded as the gold standard of lighting quality. The filament's thermal capacity keeps it glowing through the zero crossing. Fluorescent lamps have after-glow. Glowing hot arc tube of MH does the same thing. LED or its phosphor coating have almost no after glow to buffer flicker. This particular LED flickers at 100% flicker percentage (shuts off all the way each zero cycle) and ~0.45 flicker index. There's really nothing in Energy Star that clamps down on this. Until standards become established and pressure the LED industry to disclose poor performance or stop pushing out extremely flickery products, it is important to bench test a fixture before installing the lot so you do accidentally install a lighting downgrade. A fixture with this much flicker would produce multiple image effect on anything in motion and it will be obvious.
Just for your reference:
LED industry is putting effort into finding ways to lower build quality and compromise on performance parameters. The compromises are carefully crafted to leave widely published specs or those that matters for regulations and incentives alone while slicing away at unpublished specs that sometimes have dramatic impacts on the functionality of the product and encourage snap-back (putting old fixture back in).
Commercial Electric 696 626 11 in Ceiling Light, Model HUI8011L-3
1055 lumen, 17.1 lm, 82 CRI , 2764K
Rated life: 35,000 hours
shocking amounts of flicker.
Dims over a wide range without rumbling or shimmer and I can't hear any buzzing.
Power factor and THD are good.
Seoul Semiconductor SMJD2V16W2P light engine.
It's not a ballast bypass. It uses a monolithic LED ballast chip that can switch the length of LED strings rapidly in four steps to fit around the contour of each half cycle. these are the possible chain links 2, 4, 5 and 6.
Conveniently, they don't talk about flicker performance.
There six strings of 7 23v LEDs in parallel.
Strings are arranged as 2+2+1+1. Transformerless LED ballast rapidly switches extends and shortens the string length to fit the contour of sinewave, but completely extinguishes at zero crossing. There's no smoothing capacitor at all, but full extent of line frequency flicker gets spat out by LEDs. When LEDs are operated like this, it is detrimental to their efficiency compared to running all of them on a steady current. So, even if ballasting loss is reduced, it may not result in an overall efficacy gain. For the record, the efficacy of this fixture is quite poor at 60 something
Terrible power regulation and do not handle voltage variations very well. See how much the input power shifts between 114 and 126v.
The Korean light engine attaches to a thin gauge metal base that looks like the thing you put under a house plant with 3 screws and cheap feeling hardware and cover completes the rest of the fixture. The build quality feels skimpier than the average builder's grade mushroom fixture.
When I had a look inside a Lithonia Versilite in 2014, I came across the same type of low cost LED ballast that was just as terribly flickery. I was hoping something like this have long been phased out, but now I know it isn't. This is one of the deficiencies in Energy Star. It doesn't put restrictions on flicker beyond requiring the flicker to be equal to or greater than 120Hz and rectified AC power fed to LEDs without any smoothing produces flicker at exactly 120 Hz so it falls under "equal to 120 Hz", so something like this, which I think is utter junk ends up on shelves.