Comparison of a cheap Chinese LED lamp with an expensive one! Cheap LED lamps from China

I have already written several times about the fact that unknown reasons There are no good LED bulbs in Chinese online stores. Not at all.

Almost all of them are decent led lamps, which can be bought in Russia, are produced in the same China.

One day in the comments to mine, one of the commentators wrote: “I took 5w for my father. He has 15 pieces in his chandelier. I’m satisfied beyond the roof and asked for 15 more.”

I didn’t spare my hard-earned five dollars and decided to check it out by ordering two light bulbs.

The first is 5W 5B-E14 for $1.9.

We measure parameters using the device.

Instead of 5 watts we have actual 2.3 watts. The light bulb produces only 171 lumens - approximately the same as a 20-watt incandescent lamp. The lamp has a terrible color rendering index (CRI) of 63. Even the most bad lamps, sold in stores have a CRI of more than 70, and for lamps used to illuminate residential premises, a CRI of more than 80 is recommended. Light pulsation is 34%.

The second 9 Chinese watt bulb is 9F-E14 for $3.04.

We measure.

Instead of 9 W, it is three times less - exactly 3 W and this lamp produces even less light than the first - only 151 Lm - approximately the same as a 15-watt incandescent lamp. The color rendering index is no less terrible - 63.5, although the light pulsation is only 2%.

When disassembling this light bulb, it was discovered that the manufacturer forgot to apply thermal paste to the board.

The Chinese seller does not report the main parameters of the lamp - luminous flux, color rendering index, light pulsation coefficient, and does not indicate the color temperature precisely, but as a range.

The only exact parameter that the seller indicated was power consumption. And here the buyer is deceived several times, or rather, more than twice with the first lamp and three times with the second.

Such lamps can only be placed in the refrigerator, and even then they will not fit in size.

When purchasing lamps, I advise you to pay attention to the following things:

1. The lamp packaging must indicate the luminous flux in lumens (Lm, Lm), the exact value color temperature(not a range or an indication in words, “warm/cold”), index value color rendering CRI(Ra). It’s good if it says “no flicker”.

2. There should be a barcode on the lamp packaging (this is a sign that the lamp was made in a large factory and is sold in stores).

3. The warranty period must be indicated on the packaging and the longer it is, the better (lamps with a warranty of 1, 2, 3, 5 years are available). If a lamp burns out, it can actually be changed in a store without any problems.

P.s. Let's do this. If you are still sure that there are good lamps in Chinese stores, I can check it out. I am ready to order 5 lamps with my own money at a price of up to $5 each (including shipping costs), test them and publish the results. Give in the comments links to those lamps that you think are good and want me to test them. No more than one lamp per person.

P.p.s. I have already tested more than 1000 LED lamps. All results on

LED lamps are replacing other light sources. The possibilities of LEDs (LED - Light-Emitting Diode, light-emitting diode), which promise the properties of semiconductor materials predicted by physicists, have not yet been exhausted. Engineers are able to obtain more and more samples best quality and bring them to the mass consumer.

Lamps from China

China is the main supplier of LED lamps in Russian market. The advantages include their low cost. The downside is unreliability. The Chinese are not always ready to give away goods for free top quality. China's policy is to sell an inexpensive product and console the buyer: if it breaks, buy another one, it's inexpensive.

Before paying attention to the manufacturer, it is still better to give preference to well-known brands, for example Gauss, Philips.

A Chinese LED lamp should, of course, not be chosen based on its packaging. The best place to start is with products average price. The cheapest ones are obviously of very modest quality. But among mid-priced lamps you can find some real finds. This is a feature of the Chinese market and production.

There are a great many enterprises operating in China, constantly competing with each other. This time. The semiconductor industry is still developing, and leading suppliers are supplying the market with experimental batches of devices, which, naturally, are sold cheaper than proven and established ones. That's two. Therefore, buying a good Chinese light bulb is a kind of lottery for the buyer.

Before purchasing, pay attention to signs of low-quality products:

• flickering visible on the phone camera indicates a low-quality driver;
• the quality of the cooling system, the radiator should be made not just of plastic, but at least of high-quality composite materials, preferably metal (aluminum is an ideal option).

If you order from Aliexpress, then ask the seller to shoot a video. If you see such defects in the video, then do not buy or be prepared for a short service life. Nice lamp has a massive radiator with fins, lights up quickly but smoothly, and shines without flickering, without changing brightness.

Diagram of a Chinese LED lamp

LED small and medium power works for DC about 10-30 mA at a voltage of about 2.5-3 V. Therefore, in quality lamps for 220 V, several pieces each and are powered by a pulse voltage converter with PWM regulation.

The converter is manufactured in the form specialized chip, called a driver. (Actually speaking, this is nothing more than a pulsed one, not a linear one.) The drivers provide an optimal power supply for the LEDs, such that the LED lasts a long time and burns brightly. But this was done only in European and American lamps, for the most part inaccessible to the mass Russian consumer, and even if available, they are too expensive.

Diagram of a Chinese LED lamp of the Corn type on SMD LEDs 5730

Chinese manufacturers often assemble LED lamps using a simplified design. It's done like this. All LEDs are connected in series and connected to a rectifier bridge with a filter of one electrolytic capacitor. Since the resulting circuit, as a rule, operates at a lower voltage than 220 V, the remaining voltage is extinguished using additional non-polar capacitor, usually film, at the entrance of the bridge. This uses the fact that the resistance of the capacitor is reactive in nature, and almost no heat is generated across it.

The described scheme is rather imperfect. Firstly, when the mains voltage fluctuates, the brightness of the lamp will change greatly, and secondly, with increased voltage, the service life will be significantly reduced. At lower voltage, the brightness will decrease unacceptably. Tiring flickering will be observed in operation due to the fact that the filter capacitor after the bridge has insufficient capacitance. (A capacitor of the required capacity simply will not fit into the base of a Chinese LED lamp.)

Refinement and repair of Chinese LED lamps

Refinement by craftsmen usually consists of increasing the capacity of the ballast capacitor to increase the current passing through the LEDs. This helps, but is by no means a competent solution, because the first good jump voltage will damage one of the LEDs, causing the entire series group to go out.

Sometimes they try to use zener diodes, but a primitive stabilizer parallel type ineffective for such a load.

The video clip describes another type of modification: increasing the capacity of the filter capacitor in a Chinese LED corn lamp, which is being done to reduce the level of flicker.

The video does not say anything about the need to observe polarity when connecting the filter capacitor. If it is not followed, the capacitor will burst very effectively and start smoking.

What to do if the light bulb fails? Repairing a Chinese LED lamp consists of the following sequence of actions.

1. Carefully open its base, which contains the power supply circuit for the lamp.
2. Identify a burnt out LED by testing each one from the source DC voltage 3-5 V through a resistance of 500-820 Ohms. It is necessary to take into account that if the polarity is not observed, the LED will not light up, so first you need to get used to it by changing the probe probes.
3. Find faulty LED- the one that does not light up - and close it with a jumper or resolder it (observing the polarity!) from another faulty Chinese light bulb.

Chinese LED lamps for cars

In cars, LED lamps are used in parking lights, fog lights, running lights, as well as for low and high beams. Side lights with LEDs - good sources lights, economical and bright, just right for evening and night parking on the side of the roads. For headlights, bulbs with an h4 socket are produced, in which they use powerful LEDs with an average current consumption of up to 3 A (this is the driver supply current). To illuminate interior elements, they use not lamps, but LEDs.

The rear part has a large cooling radiator, and sometimes even a fan to enhance airflow. LED headlight bulbs are economical, but have inferior optical characteristics than halogen ones. This is explained by the fact that it uses three LEDs and the source is not a point source, as is the case with halogen ones. The increased scattering of LED headlights occurs according to the laws of geometric optics and does not depend on any “intrigues” of manufacturers or service station workers during technical inspection.

Results

To summarize, we can say that it makes sense to buy high-quality Chinese LED lamps. Avoiding Products poor quality, You will not need knowledge about modifications and repairs. Remember, when purchasing, you need to make sure that the lamps do not flicker and that the radiator is made of high-quality materials. Somewhat unpresentable appearance The light bulbs should not be confusing - they are handmade in China.

Chinese online stores sell hundreds of models of LED lamps. Over the course of a year, I ordered twelve lamp models from different stores.

Unfortunately, it turned out that none of these lamps are suitable for lighting residential premises.

Each of them has several disadvantages from the following list:

Power and brightness are much less than stated;
Uncomfortable lighting color, low CRI;
High light pulsation (flicker);
Narrow lighting angle, the lamp shines only forward
Inability to work with switches that have an indicator.

I have the feeling that there are no good LED lamps in Chinese online stores at all. At the same time, in Russia you can buy many good LED lamps from Russian and international brands, which are produced in China. Perhaps the reason for this strange phenomenon is that brands control Chinese manufacturers and demand that they adhere to technology, while the Chinese themselves make light bulbs “anyhow”, trying to save on everything.

So, 12 lamps.

Results of measurements made using Viso LightSpion (https://ammo1.livejournal.com/470834.html), pencil flicker test (https://ammo1.livejournal.com/418344.html) and testing with a switch with an indicator , are tabulated.

As can be seen from the table, none of the 12 light bulbs produces the promised luminous flux. IN best case scenario we get 84% of what was promised, at worst - only 30%.

According to the results of my measurements, a regular 75 Watt matte incandescent lamp gives 750 Lm, 60 Watt - 555 Lm, 40 W - 310 Lm. Accordingly, only 9-watt lamp No. 2 can replace the usual 75-watt lamp in brightness, and No. 3 - 60-watt. Lamps No. 1, 6, 8, 9, 10 can replace the brightness of a regular 40-watt lamp. The remaining five lamps can replace only 15-25 watt incandescent lamps in brightness.

It is believed that for residential premises (CRI) should be higher than 80. Of the 12 lamps, only the first lamp is close to this value; all the others have a much lower CRI value, which means that when illuminated by these lamps, the colors of all objects will be significantly distorted.

Seven lamps out of twelve have a strong pulsation of light (flicker). These lamps are definitely not suitable for residential premises.

Only three lamps (No. 4, 5, 6) work correctly with switches that have an indicator - when the switch is turned off they do not light up. Four more lamps flash periodically when the switch is off. The rest burn weakly (these are lamps without a driver - all their electronics consist of two capacitors and a diode bridge).

All twelve lamps have an uncomfortable lighting color. For many it is greenish. The light of these lamps can never be confused with the light of an ordinary incandescent lamp. I note that there are many good LED lamps, the light of which cannot be distinguished from the light of an incandescent lamp.

Screenshots of Viso LightSpion

I did detailed reviews two lamps:
Lamp No. 1 E27 Bulb 7W:
Lamp No. 4 E14 Candle Dimmable 9W:

For all other lamps, I will give photographs of comparison with the light of incandescent lamps, since they were already made, but by and large everything is clear with them.

Details about light bulbs

All photos were taken on manual settings With the same values exposure and ISO. White balance was set to 3500K.

Lamp with broken glass(It's glass, not plastic).

Comparison with a 40 W incandescent lamp in a photo cube.

Comparison with a 60 W incandescent lamp in real conditions.

2. E27 Bulb 9W. Inside there are many small LEDs. The light is bright, but has a green tint.

3. E27 Bulb COB 9W. Inside is a ring-shaped COB module. The light is similar to the previous lamp - bright with a greenish tint.

5. E14 Candle Dimmable 12W. About this light bulb:

6. E27 Corn 6500K 9W. This light bulb was purchased by mistake. I didn’t notice that its color temperature is 6500K - cool white light.

7. E14 Corn COB 8W. Corn COB. This and the next two lamps the simplest driver no active electronic components. The lamps flicker heavily. When used with a switch that has an indicator, the lamps glow dimly when off.

8. E27 Corn COB 9W. The real power of this lamp is exactly the same as the previous one - 5.3 W, but it shines a little dimmer.

9. E14 Corn COB 7W. Of the three COB corn lamps, this one has the lowest power (claimed 7 W and actual 5.1 W), but it shines the brightest.

10. E14 Corn 5.5W. One of the few corn lamps with a full-fledged driver, due to which the lamp does not flicker. But the phosphor is still bad, so the light is greenish.

11. E14 Corn 7W. I don’t have any photos of this lamp, but believe me, everything is no better here.

12. E14 Corn 5.5W. The lamp is a misunderstanding with a luminous flux of 133 lumens, which can compete in brightness only with a 15-watt refrigerator bulb.

I admit that there are good ones in Chinese online stores led light bulbs, but I haven’t come across any of these.

© 2015, Alexey Nadezhin

I have collected a few Chinese smd5730 lights, I decided to tell you a little about them. In total I have 4 different LEDs. The first ones are quite good, Chinese LEDs, they have already been reviewed. - the cheapest 5730 on aliexpress. I bought them for $1.15 per kilogram, 200 pieces. The third and fourth ones are from the most ordinary meter LED line on an aluminum substrate, purchased offline for $2, cold and warm color temperatures.

To make it easier to compare them, I cut the same aluminum ruler into minimally divisible pieces, 3 diodes each. I left two with the original diodes, and soldered the remaining two to those purchased on Ali. Unfortunately, I don't have a hairdryer yet. Soldering LEDs with a soldering iron is somehow not very good - most often it melts or breaks. I did it the simple way - I heated the iron and placed the pieces of the ruler on the work surface of the iron. Before this, of course, I coated the diodes with flux. I use Polish flux bought at a radio store:

pasta do lutowania

And now the power is supplied with the same current of 50mA:


As you can see, the result is the same.
If someone thinks that with a lower current the rulers shine brighter, I will say right away that they do not shine brighter, but the difference is due to the shutter speed of the camera.

1. “Real smd led 5730”, a review of which I gave a link at the beginning.
2. Warm LEDs from a line purchased offline
3. The same, only cold
4. The cheapest diodes from Aliexpress

I also decided to measure the current and voltage drop at 150 mA of each diode separately. I chose the average voltage - 3.2V. I didn’t take any photos, I’ll just write:

current at 3.2V/voltage at 150mA
1. 151.1mA/3.2V
2. 84 mA/3.65V
3. 81.2mA/3.55V
4. 49.8mA/4.26V

As you can see, the difference is big. Diode crystals are also different:

Results:
The first LEDs are the highest quality, their crystal is really 0.5W. Its size is 15x30mil. Previously, this seller had diodes with an even larger crystal - 20x40 mil, but its power was the same. Probably the crystal manufacturing technology has improved.
The seller promises 50-50Lm at 3.0-3.2V and 150mA. There are also diodes available with temperatures of 3000-3500K, 5000-5500K and 6000-6500K.
The second and third ones are of average quality, the power is about 0.25W. I can't say anything more about them.
The latter are the cheapest and, accordingly, the worst. Power less than 0.2W. The crystal is small, I think from 2838. In the description, the seller does not indicate either the manufacturer of the crystal or its parameters. Only that it is smd5730.