An Interesting Electronic Load Option

Yesterday I was browsing AliExpress and came across an interesting take on an electronic load. I read a little about it and decided to share it with you in case it comes in handy.


At first, I thought I’d add it to the weekly roundup of interesting AliExpress finds, but waiting another week seemed too long, and I really wanted to share this discovery, so here you are reading this post today.

I’ve mentioned Atorch and HiDance loads before. They’re handy and interesting, with power ratings of up to 150 or 180 W, and are therefore available in two versions. They cost around $25 — link


I also wrote about their newer version, which has a large screen and, most importantly, can connect to a computer or smartphone while retaining the key features of the earlier versions. The 150 W version costs $28 — link


But I came across an even more interesting option, without a heatsink. That immediately brings the price down, since you don’t have to pay for the heatsink itself, and shipping costs less because the heatsink is the heaviest part. The result is a price of just $19.50 for almost the same thing — link.


According to the product page, the package includes:
1. DL24 PCB board (heatsink not included) x1
2. DC 12 V 1 A power supply x1
3. 2 m PC computer online cable x1
4. Temperature sensor x1
5. Red and black single-wire alligator clip cable x1
6. US-to-EU adapter x1

In other words, it’s a complete kit, just without the heatsink.


The board has a whole bunch of connectors, including:
1. Power input for the load itself
2. Cooling fan connector
3. Terminal block for connecting test leads or the output of the power supply under test
4. 5.5 mm jack for connecting power supplies under test
5. Several USB connectors of different types for testing USB chargers
7. Temperature sensor input
8. MicroUSB port for connecting to a computer
9. Separate calibration connector


It’s very convenient that there are three types of connectors for testing USB chargers. The only thing missing, perhaps, is USB-A, but it’s not really needed.


So you can test pretty much anything :)


The display is large and informative, although I find it a little cluttered. The control and menu navigation buttons are on the right, along with a buzzer. The Bluetooth module for connecting to a smartphone is above them, and it probably connects to a computer too.


The load also comes with updated firmware. I didn’t immediately figure out what had changed, but then I got it: you can now set the cutoff voltage to 0 V instead of 2 V, and it also displays the source’s internal resistance (or the battery’s, if that’s what you’re testing).


It’s also worth noting that the load can operate in four modes, not just two:
CC, or Constant Current: current regulation
CV, or Constant Voltage: voltage regulation; the load prevents the voltage from rising above the set value by increasing the current.
CP (CW), or Constant Power: power regulation; the device varies the current to maintain the set power consumption.
CR, or Constant Resistance: constant resistance; the load current changes automatically depending on the input voltage.


There are plenty of settings, and the menu is available in Chinese or English.


It’s also important to note that the manufacturer lists the following specifications:
Test voltage: 2–200 V
Operating current: 0.2–20 A

And the power limit is no longer 150/180 W like on the models with a heatsink, but up to 1000 W, i.e. With an adequate power stage and cooling, you can test either up to 200 V at up to 5 A, or up to 50 V at up to 20 A, including settings in between.


Of course, they suggest using a heatsink from a computer processor, but that’s not very interesting, since its power dissipation capacity isn’t all that high either.


So what should you do?
To start with, you could buy a simple electronic load board with an LM324 op-amp and use it as the power stage. You’ll have to replace the power transistors, though, or use several of these boards. The board costs about $9.5 — link


But there’s an even simpler approach, and in some ways it’s actually better: build your own power stage, as I did in this review.
The circuit is simple and basic, though you’ll need to desolder the original transistor and figure out the best way to connect the power stage. Unfortunately, I can only describe this in theory, not step by step, since I don’t have the module in question to experiment with :(


Next, find suitable heatsinks and get a few power transistors.


Then build your own power module, using the board shown only as a controller and measurement unit.


The result is a compact, powerful, and fairly convenient electronic load. The store page even shows an example of this kind of setup.


In short, I definitely recommend it. At $20, I think it’s more than reasonably priced, given all the useful features. I’d like to try one too, and might order it, but I already have so many loads at home that I’m not sure I’ll buy another one just for experimenting.
If only they’d thought to either leave out the power supply altogether or offer it as an option. That would make it cheaper and more convenient for electronics hobbyists, but alas.