Reduce flickering on cheap 220v AC GU10 LED Lamps

Question

As I am unable to find exact answer anywhere, I am looking for some help. First of all, I'll explain the current situation. I have a freshly built appartment where noone ever lived before. We decided to go for LED lights in all rooms and all lightning zones. The wiring is done for every room and every room has its own fuse. In my country we have 220v 50 Hz. Time has come and we started looking for GU10 220v LED bulbs. We bought a set of 9 bulbs (4 or 5 W each) for one room and another set of 15 bulbs (3w each) later for second room. Also, we are using the touch switches from Livolo brand everywhere, so, no mechanical switches. None of the currently installed bulbs are dimmable, but we plan to add dimmable ones for living room.

So far, so good, everything works, except the strange feeling to my eyes on movements. I started some small research. I found out what is AC, what is DC, what is 50Hz, and after all, what is flickering and what is a cheap LED Lamp with bad LED driver inside. I also tried capturing some videos using manual shutter and the flickering was visible. Considering all this, I have some questions, but please answer them as simple as possible.

1. Is there a technology (some box, converter, rectifier, capacitor, etc.) that can be installed already at the beginning of the circuit (after the fuse box) to drive all the lights in appartment with reduced flickering safely, while keeping in mind we're using touch switches? With technology I mean a ready made product which is safe, rated for the total wattage and is in one piece.
2. If yes, will it work with the touch switches and the future dimmable touch switches and dimmable leds? Livolo switches are phase-cutting / Leading Edge dimmers.
3. Will choosing a more expensive LED lamps solve the problem with flickering?
4. If nothing can be done, except buying better LED lamps, which brands are flicker free?

At the moment we have only bought 9 + 15 leds for 2 rooms, 6 high lumen white light led lamps for bathroom, 1 high lumen led + 2 low lumen spotlights for toilet, none of them dimmable. Touch switches cost us a lot of money, so, they won't be replaced. If you require any morespecific information to answer my question, please ask and I will give everything I can find.

I just can't describe my anger on all this LED situation... if I ever knew anything similar will happen, I would have just chosen another solution, before buying...

P.S. Sorry my primitive english, it's not my native language. And thanks in advance!

Answer 1

the flikcering issue caused by 100 Hz frequancy on driver, solve this problem only one way that using flikering free LED lamps which will be use a flickering free driver inside.

you can easy use a camera to check if it is flickering.

I know a China supplier have such GU10 bulbs, refer to www.henhui-tech.com or www.isoled.at also have such bulbs.

Answer 2

You can't easily re-engineer the existing lamps, but you can look for reviews, particularly in you area, for a better replacement.

One thing that might help while using a computer or other device with a display is to change the refresh frequency. You may have to experiment, but usually the worst setting is close to line frequency, which causes a slowly moving vertical disturbance.

Answer 3

This will depend a bit on the bulbs and switches/drivers/dimmers in question and your frequency sensitivity.

Some bulbs are basically full wave rectifiers built out of LEDs, so those will go to twice the system frequency (1 flash on the positive half and 1 flash on the negative half.

Other bulbs have a PWM current regulator with output current proportional to input voltage. If they get quite hot and the electronics get messed up you definitely might end up with the output frequency becoming visible.

LEDs in pulse mode tend to have flicker become more visible at low power at a given frequency.

I believe if you try to choose quality dimmable bulbs it will probably resolve this problem. In order to make them dimmable, they have to include a bit more control circuitry and it's more likely that output PWM frequency was evaluated. Dimmable 60W equivalent LED bulbs are quite reasonably priced where I live, although those for special fixtures often still charge quite a premium.

I recommend getting or borrowing a few bulbs of different brands but the same socket type as the currently offending ones and see if they perform the same.

If this resolves the issue, it may be a problem of bulb quality. If simply putting a new bulb of the same type in the socket temporarily resolves the issue it indicates your LEDs are probably overheating and you should look at fixture choice and design, or LEDs that are designed for enclosed fixtures.

1.) This relates more to initial system design. While you may have a wiring problem, and that could hypothetically affect this, it's likely not the case, unless you choose a DC lighting system when initially wiring the house, which can simply amount to a different set of complications. Usually AC is used up to the area your LEDs are being used, at which point a larger AC to DC LED driver is used to drive multiple LED fixtures. One thing you could do is in a room with many LEDs, you can use a small amount of capacitance to cause the signal to lead a little bit and by different amounts per bulb. This is used in flourescent light flicker problems, but this will only work if you have the full wave rectifier type bulb and it's a lot of work per fixture.

2.) Performance will be inconsistent as some of these dimmers will chop up your power signal differently.

3.) Not necessarily more expensive ones, but better ones will likely do it.

4.) This will really depend on your sensitivity, but I've had fewer failures with brands that use better parts, like CREE, Luxeon or Nichia emitters. I think the companies that cheap out on design often cheap out on parts as well. That said, The price ratio from cheap off brand bulb to high end bulb is often high enough that I can just buy all the off brand bulbs until I find a good one. Some of them may also be government subsidized in your area, resulting in bulbs that appear bargain-basement cheap, but in reality are quality bulbs that were heavily subsidized due to an environmental program.

Answer 4

LED light flickering is a well recognized problem, but mostly by frustrated consumers. Manufacturers don't seem to bother much with flicker characterization. See the problem overview in LEDs Magazine.

For a particular bad bulb you probably can't make much of improvement. But you can get a better, less flickering bulb if you consult with this consumer product review site, LEDBENCHMARK.

Answer 5

except the strange feeling to my eyes on movements

Cheap way to check if a LED bulb flickers:

Turn off all other light sources. Look from left to right as fast as you can with the LED light in your field of view. You will notice the light leaves a "trail" in your vision. If the trail appears dotted, then the bulb is flickering.

You can also aim your smartphone at the light, go to photo mode, and turn the phone left-right or up-down. The light will leave a "trail" on the screen. Again, if it is dotted, this is flickering.

there a technology (some box, converter, rectifier, capacitor, etc.) that can be installed already at the beginning of the circuit (after the fuse box) to drive all the lights in appartment with reduced flickering safely, while keeping in mind we're using touch switches?

Short answer: yes for 12V LED lights, no for mains powered lights.

The AC voltage is a sine wave.

Maximum voltage is only available on the peaks. Your LED bulb requires a minimum voltage to turn on, which depends on the internal circuit. It certainly won't turn on with zero volts. It it has a switching driver, it could work from say 80V to 300V. If it has a dumb driver, the minimum voltage will be a lot higher.

So, unless there is an internal capacitor to store energy to power the light during the time when mains voltage is too low, it will turn off 100 times per second during the part of the voltage waveform that is too low voltage. This is flicker.

However this capacitor adds to the cost, and reduces PROFITS.

A solution is to power the bulb with DC voltage. Since the voltage is constant, it will not flicker. This is great for 12V LED bulbs, which run on 12V AC but usually work fine also on 12V DC, getting rid of flicker as a bonus.

However, your touch switches most likely use triacs to switch the bulbs, and triacs only work on AC.

A triac is a type of electronic switch that is cheap and rugged, but it has one drawback: it can be turned on via an electric signal, but it can't turn off unless the current through it goes to zero. This is fine for AC, as current goes to zero twice per cycle, so the triac will turn off. With DC power, it will never turn off, so the lights will stay on. Not practical.

So you'd have to add a rectifier and smoothing capacitor between each switch and each light.

This gets complicated, and also dangerous since capacitors charged at mains voltage will stay charged even if you turn off the power to change a lightbulb. That would be a great way to get shocked, fall off the ladder, and break your neck.

I'd recommend changing the bulbs instead. Some LED bulbs will flicker because the manufacturer "cost-optimized" the smoothing capacitor by removing it entirely, but better quality bulbs have a capacitor of proper value and do not flicker.

Try googling these EAN codes: 4058075260115 or 4058075260139

These are dimmable 90CRI GU10 bulbs in 2700K and 3200K.

They do not flicker at all. They are cheap and reliable, I've had lots of them in my home for a few years without any failure yet.

I really like the 3200K version. It produces a pleasing warm white without greenish or purplish weird tints, and color rendition is very good. This alone is worth the upgrade cost. If you have never heard about CRI or color rendition, order a couple of these in 3200K color temperature, and compare with your current bulbs.