20-Watt LED Driver or

I got so into experimenting with LED lighting and modifying light fixtures that when I was offered a product to test, I couldn't resist and decided to try a factory-made LED driver.
If you're interested, read on to see how the idea developed.

As I mentioned in the introduction, the driver was provided free of charge. That doesn't really matter here, though, since the point of any review is to show what a product is like and whether it's worth buying. I promise to be impartial and show you what it's really like. Besides, I haven't seen a review of a 20 W driver here yet.

First, some background. I've long noticed that fluorescent light fixtures built on the principle of “the cheaper, the better” have a characteristic flaw: if you switch them on and off frequently, they don't last long—neither the lamps nor the electronic ballasts themselves.
I have a couple of fixtures at home with branded ballasts, Vossloh Schwabe and Philips. They work great, but they tend to be rather expensive, and quality Philips units have disappeared from stores. I'm still wary of using LEDs for the main lighting, but they're perfectly suitable for secondary lighting. I'll describe one such option in this review.

But I'll take things in order.
The driver arrived fairly quickly, in about three weeks, though I can't say for sure since it was shipped without tracking. It came in a standard yellow padded envelope, and the driver itself was in a zip-lock bag. Given its solid, potted construction, though, it's hard to damage. Nothing particularly interesting—the packaging was just packaging.


The input cable and output wires are the same length: 27 cm. The output wires have very soft silicone insulation (where can I buy wire like this separately?).
The case measures 75 × 30 × 20 mm; including the mounting tabs, it's 90 mm long.


The back of the driver is potted with a substance that looks like epoxy resin, so it can't be disassembled or repaired. That's a shame; it would have been interesting to try making a driver like this myself or modifying this one. But I specifically wanted an IP65-rated unit. Well, you get what you ordered, so don't complain. :)


Specifications claimed by the manufacturer.


Key driver specifications.
Number of LEDs: 6–9.
Driver output voltage: 28–40 V.
Current: 600 mA.
The seller lists it as “20-35V 600mAh 20W LED Driver (10 series 2 parallel)”.
That doesn't quite add up. And even 6 LEDs would give a maximum of 24 V, which doesn't match the manufacturer's figures either. But the tests will show who's right.

The most I could find out about what's inside is that the output capacitor has a capacitance of 100 µF—though that's only an estimate.
By the way, the driver takes about 0.5–0.7 seconds to turn on, which is a little annoying.

Next, I started testing it (I was curious myself).
With no load, the driver outputs about 44 V (for reference, the mains input was 230 V).


First, I loaded it with a 100 W LED array (10 × 10 configuration). The voltage dropped to 30.9 V, and the current was 0.57 A, giving a power output of 17.6 W.


After that, I moved on to testing it with the load I planned to use.
10 W LEDs (3×3 configuration)

2 LEDs in series, voltage 19.04 V, current 0.58 A, power 11 W.


3 LEDs in series, voltage 28.11 V, current 0.57 A, power 16 W.


And finally, a test with what I planned to connect to it: 4 10 W LEDs in series. The voltage rose to 37.08 V, the current dropped to 0.53 A, and the power came to 19.65 W.


This is effectively the driver's maximum output. I think that's pretty good.
The load is a little unconventional, but that makes it more interesting.

It's interesting that the LEDs are slightly different. You can clearly see the chips in three of them when they're on, but the fourth one (top right in the photo) looks kind of blurred. It's less noticeable in the photo. No idea why—probably a different batch.


For the connoisseurs.

That wraps up the experimental part; now it's time to move on to the practical side.
As you can imagine, a driver sitting on a shelf isn't doing anyone any good—unless it's propping something up :)
In one of my reviews, I modified a Chinese-made light fixture. This one is very similar: also a light fixture, also made in China, and just as common as the previous one. And it suffers from the same unreliable operation.


Summary.
The driver is perfectly decent. Its current is slightly below the manufacturer's rating: 550–580 mA versus the stated 600 mA.
Even at maximum power—and in a setup that's not quite within spec—the temperature is perfectly reasonable. The manufacturer specifies a maximum of 75 degrees; in my closed housing, it reached about 60. We'll see how it holds up.
Ripple is low; it passes the pencil test, but adding capacitance at the output would probably reduce it further.
The delayed startup is a little annoying, but that's a matter of personal preference.

Whether to buy it, and whether it's worth the money, is up to you. In this review, I tried to show its real-world performance as accurately as possible. I hope I succeeded.
I think that's everything. Special thanks to everyone who made it to the end.

The driver was provided free of charge for testing and review by the Chinabuye store.