Review: Bedtime Bulb E27 LED (2200K, CRI95)

Thank you for confirming the Bedtime Bulb has the fluctuations that maukka reported.

His review of the Remez SunLike E14 LED bulb (3000K, CRI95) reports:

I would buy the Remez, not the Bedtime

What sort of fluctuations ? Is it a rare short dip and back to stable or is it lasting alternating changes ?

The only detectable fluctuation we manage to see is a short dip in intensity when our AC compressor turned on when a lot of other appliances where on also

Yes, it appears as a dip whenever there is a jump in the mains voltage. A sudden jump of 1 V is enough to be noticeable. In both directions. The brightness an the mains voltage seem to be proportional.

I suspect when this happened in our little extreme electrical load experiment that the voltage change might have been much greater than 1v since i’ve been told even the plasma TV went dark for moment when i was looking at the bedroom bulb.

Thanks for the feedback so far. We have two people who have noticed any kind of brightness change during normal operation. Six people have not noticed any change. We are still continuing the investigation.

50% of people dont notice flicker
25% dont care if there is flicker
25% wont buy a product that has been tested by reputable people, who know what they are talking about, and have both calibrated instruments and trained eyes

out of every 8 people, only 2 care enough to find a light that does not flicker

I appreciate that you care a lot about the flicker issue. Trust me, I do as well (both visible and invisible flicker). That’s why we’re running this investigation and have delayed the launch of the product until we have more info.

However, that conclusion is not correct. I specifically asked all the testers to look for the issue. No instrumentation is required to do a check for the visible flicker we are talking about—you either notice it or you don’t. Seeing if it correlates to voltage changes is nice to know and helpful for when we do a redesign, but not necessary to verify the behavior.

Please take this in the kindest way that I would appreciate more patience as we carry out this test. You wouldn’t get this kind of attention and openness from pretty much any other manufacturer.

For the purpose of adding context, the local final transformer of my electricity provider is 20 meters from my house and my household is the only permanently living in the little hamlet, i wish i had the equipment to log my AC voltage fluctuations, i suspect it’s very clean.

Thanks a lot!

Sorry if I’ve overlooked something but what are you all referring to as a flicker? As in the light dims and then gets brighter? Or as equivalent to visible PWM in a flashlight? I feel I am picky about PWM.

I’ve been using the bulb the past 4 nights and not noticed any dimming by eye. Looked through iPhone camera and could not detect anything either. I don’t have any scientific way of testing but in real use I am pleased and would recommend. I am in the US.

Hey Bardo219, thanks for giving BB a try. In this case, we are looking for visible brightness changes every few seconds or minutes for the European bulbs. The “invisible” flicker is very low at around 3% modulation (120 Hz in the US and 100 Hz in Europe).

The US bulbs don’t have the problem, except in rare instances. So thanks for adding another data point on that front.

Let me know if you do ever notice anything. Otherwise, enjoy!

Wait, is there a difference in construction of the European and US bulbs?
Or is the only difference the AC power frequency?

Assuming there’s something different about the hardware, if you put a “European” bulb on US electricity or vice versa, what happens?

The main difference is the driver voltage—it’s a similar design but with different components. They will both work at 50 and 60 Hz, but the US bulbs will only work at voltages found in North America (usually centered around 120V), while the European bulbs will only at European voltages (centered around 230 V).

The US bulbs immediately die at higher voltages. The European bulbs malfunction at lower voltages. Note that we do not recommend even trying this. It’s not safe.

Edit: I should add that they meet UL, CE, etc. so it shouldn’t kill you. But please don’t try it.

Sounds like you might want to check that the parts you’ve been buying are within specification.

Not to say that Chinese suppliers don’t do adequate QA and QC and ship poor products, but … chabuduo reins.

And do they come to you in ESD-protected bags, or just polyethyene?

Also check whether your supplier uses adequate electrostatic discharge control when building components. Zapping a semiconductor doesn’t generally kill it dead, it instead changes the level at which it’s a “semi” conductor — the line between being a conductor and an insulator, the threshold at which it operates, gets altered by electrostatic discharge. It’s been wounded.

One component a little off spec is probably tolerable. Several or a handful of components all out of tolerances adds up to malfunctions like flickering.

Yep, part substitution is something we’re looking into. From what we can tell so far, the components don’t seem to be ESD-damaged, but they may be slightly out of spec. Not sure yet, though.

If they’re consistently out of spec (like say plus or minus ten percent rather than five percent, when +/-five is what you thought you bought), then you may be seeing “”quality fade”:quality fade" at DuckDuckGo in action.

If they’re all over the map, that would sound more like “wounded” (ESD-damaged) components.

Thanks, we’re investigating.

You can get some of the Sunlike bulbs in 3500k

Sunlike8 can be mixed to 3500k Review: SunLike8 SMD SAW E27 LED bulb (4200K, CRI98)

Someone asked about REMEZ 3500k. REMEZ can be 3000k and 5700k ONLY.

I am going to produse SunLike5 with 2200k SOL leds

I believe that what is happening with the Bedtime bulb is that a large draw on the mains decreases the current to the circuit which is similar to what a dimmer does. The driver sees the decrease in current as a dimmer and decreases output. When the mains stabilizes after the in rush to the motor, the output returns to full. Lamps that don’t exhibit this behavior are likely not “dimmable”.

I don’t know if it’s possible for a dimmable lamp to not react in this way unless it could be programmed to not decrease output unless the current is decreased for >1 second. This would cause a delay when utilizing a dimmer which many users would not like.