Menu

Testing “cheap” Aliexpress power supplies 2024

Many years ago I did a few articles and videos about buying power supplies from China and most specifically Aliexpress, the focus then was to see what kind of quality of the power output was.

In 2024 I decided to do such a test again but the setup was a bit simpler, buy a few power supplies that pop up on Aliexpress and just load test them. The reason for this is because a lot of power supplies had started popping up which are branded “LED lighting only” power supplies and well, that was a bit suspicious to me! What does an LED require different then any other device? What makes a power supply specifically for LED lighting? Well if we’re talking a normal Constant Voltage power supply, nothing really. So I figured it was likely a marketing trick to hide their real capabilities.

And so I bought 4 samples and I did a live stream testing them. In these tests we only did some load testing with my electronic loads, no ripple tests or anything like that and well, the results were quite interesting.

Power Supplies tested

Livestream of the testing

The results

Well if you watch the livestream the results are quite clear, these power supplies deliver nowhere near their stated ratings. Basically the three smaller supplies were only able to deliver about 30% of their rated 300w. So a 300w is really a 100w max power supply? It seems so!

The “LED supply only” trick

But then how are they selling it as a 300w supply? Well the built-in protection mechanisms is such that it will lower output voltage when the draw is too high, because of this the LEDs see a much lower voltage then what they are rated for and in turn, because they are constant voltage LED strip, will automatically start drawing less power! This means when you hook it up, everything seems to be working fine, but unknown to you, your LEDs are running much more dim then what they are rated for. I also demonstrated this in the livestream where we hooked up 5m of 38.4w/m LED strip so it should use 192w or /24v = 8Amps. But in reality it was getting below 4A at a much lower voltage so was only using about 90w in reality, less then half the potential the LED strip has! But you as the consumer would never know without explicitly measuring it, the power supply says 300w on there so…. yeah, gotcha!

So be warry of this, this is the reason they notice this is an “LED power supply only” because then that trick works, but of course it does not powering anything else, and my tests clearly show this happening.

 

To buy or not to buy, that is the question

That’s a bit of a tough one, basically all these power supplies are heavily overrated in their figures. It states it’s a 24v 300w PSU so it should be able to deliver around 12,5Amps but most of them crap out around 4Amps…. That’s much less then even half of their stated rating, so that’s horrible. That said, they are quite cheap and for the price, maybe what they can actually deliver is, ok?

It’s up to you really, the only power supply of the tested ones here I could maybe recommend is the BTF one. It survived all tests perfectly fine and worked as it should. I am a bit worried about longevity with that one and maybe safety (I can’t really speak for it), but if you are on a budget and don’t leave it running unattended, it might be a viable option for you, it also costs a more realistic amount of money vs the very cheap prices of the other ones!

But then, what should I buy?

Well, as discussed in the stream many times, I really like the Meanwell brand of power supplies and can’t recommend them highly enough. As you could see at the beginning of the livestream, the “benchmark” Meanwell power supply we tested performed great and showed all of them how it’s done basically. So for any project you need to “just work” and you might also want to leave unattended or built into some cabinet somewhere, get a Meanwell, it will serve you perfectly for many years and you can have peace of mind you at least don’t have to worry about that part of the project. For the other parts, I make controllers to take away to worries there too! 😉