LED strip or

It all started when I got tired of replacing bulbs in small light fixtures. I decided to get to the bottom of the problem—maybe not forever, but at least for a long time.
Read on to see how it turned out.

I looked at various LED strips on AliExpress and settled on one with 5630 (5730) LEDs, 60 per meter.
The seller's description said the strip was 75 W, but one of the reviews said—and I quote—
Realno 12v — 7A. Chisto belii, ne sinii, ne goluboi Tolko podsoedinjat ne bolsche 2x metrov ili s dvux storon t.k. bolschoe padenie naprjagenia REKOMENDUY
Of course, I didn't believe this information, but the price was low. I figured that even if it was less powerful (though I'd have been more surprised if it actually matched the specs), it wouldn't be a big deal. After I left my review, other reviews similar to mine started appearing for the seller.
But let's take it from the top.

The strip arrived wound around a standard reel and packed in a standard little bag. Nothing unusual—in fact, it was a bit boring. They could at least have made the reel a fun color or drawn a smiley on the bag.


The reel itself arrived broken (probably standard, too). This was the first time a package of mine had arrived damaged. I think it was broken in China, though the postal service could have done it too—maybe that's how they packed it in the “consolidated package.”



I measured the strip's current draw and, naturally, its power consumption (how could I not?).

At 11.9 V. The power supply is old and can't maintain 12 V at this current; I also tried a battery.
A small correction to the test: I messed up and took the measurements after cutting 35 cm off the strip. It wouldn't have made much difference to the result, but next time I'll measure first and cut later.
Voltage across the strip: 11.9 V


The current is 2.16 A.


That works out to about 5.5 W per meter.

I decided to check how much voltage reaches the end of the strip.


I was curious how much the brightness differed between the beginning and the end of the strip, since I often see people on forums saying they connected a strip and it shines equally brightly from end to end.
You can see the difference in brightness in the photo; in person, it's a little more noticeable. The beginning of the strip is on the left, the end on the right.
If you look directly at the strip, it just dazzles you, and it's impossible to tell which part is brighter and which is dimmer.


After all these experiments, I decided to figure out why it draws so little power and where all the watts went.

I cut off a 5 cm piece of the strip so its length wouldn't affect the measurement.
I applied 12 V and got a current of 38 mA.


Now, if you recalculate the strip's power without accounting for the voltage drop along its length, you get about 9 W per meter, which is also clearly less than the seller claimed. I wrote to him about it, but he brushed me off, saying it was the manufacturer's fault. I was already thinking of asking for a refund, but then I took a closer look at the strip and saw that it had 39 Ω resistors, whereas similar strips usually use 24 Ω ones. I figured that if it wasn't bright enough, I'd replace them (as it turned out, it wasn't that simple).


I decided I was happy with it and confirmed receipt.

So, we're done with the “Axe” review; now it's time for the “Soup.”

If you're curious what happened next, the rest is under the spoiler.
Warning: lots of photos and text.


I gathered all the parts I needed (just by rummaging through my boxes, since there’s nothing unusual here apart from the transformer and IC, and I had those too).
Some of the parts in the schematic can be omitted or replaced. You can also reuse some components from a dismantled electronic ballast, such as the inductor core, input capacitor, and some of the diodes. However, to use the transformer core from the lamp, you’ll need to extend the board by about 2.5 mm where the transformer is mounted.




I wound the transformer, soldered the first board, cleaned it, and checked it. Everything was fine, except the output voltage came out to 12.26 V (that’s about what the calculations predicted, but it wasn’t critical), so I left it as is.
Both boards started up right away, with no adjustments or setup. Still, it’s best to power up something like this through an incandescent bulb the first time. In this case, I used a 25 W bulb.


I got everything ready and started assembling the whole thing.


I assembled it, glued it together, and tested it. It gives off a pretty decent amount of light. I managed to fit a 30 cm strip, with the power connection in the middle (no need for extra losses in the strip’s thin traces).


In terms of brightness, it’s comparable to (maybe even brighter than) an 8 W lamp (though I’m sure it was really about 6 W before).
The light is white, with no green or blue tint—just excellent white light.


As it turned out, there was no need to replace the resistors; the brightness would have been fine as it was. I even thought about putting them back, but accidentally threw them out with the trash from my workbench. The supply voltage is now 12.26 V, and the current is 318 mA. The resistor drops 1.27 V, so each LED gets 3.65 V—a clear overload, which says a lot about the LEDs’ not-so-great quality. But we’ll see how they hold up. The power delivered to the LEDs themselves is 3.5 W.

After installing it in its original spot, it seemed noticeably brighter and a little whiter, but the strip is more directional than the fluorescent lamp.
It doesn’t heat up much, and you can barely notice it. Considering the lamp is rarely left on for long, it’s not worth worrying about at all. I could have done without any metal parts, but it’s better to do things the right way; doing them the wrong way will happen on its own.

I didn’t like that the LEDs reflect off the chrome clothes rail, but the family said it didn’t bother them, so I decided not to worry about it either.

While I was gradually writing and editing this review, I converted the second lamp as well.



In my opinion, even with the power coming in below spec, this LED strip is still worth considering. But next time I'll look for something more powerful and better quality, most likely from a different seller.
I didn't like that the power rating is overstated and the voltage drop along the strip is quite large (I don't know how other strips perform, since I have nothing to compare it with, but this one disappointed me).
The seller knows perfectly well what they're selling, even though they claim it was probably a manufacturing mistake.
But I'm almost certain that even if they'd fitted proper resistors, the result would still have been a mess: the voltage would have dropped even more toward the end of the strip, the LEDs would have been overloaded, and it still wouldn't have reached 14 W.
But it's perfectly fine for small projects.
I liked the price, the LEDs are reasonably bright, and the light color is good.

The goal of this modification wasn't to save electricity or money on a large scale. I just wanted something that would work and not break, and besides, making something with your own hands is enjoyable in itself.

I hope someone finds this review interesting and useful.