Adjustable DC Power Supplies are very useful to have around. You don’t have to spend a ton on high-quality bench supplies. Tiny DC-DC converters are perfect for small DIY projects. The ZK-4KX Buck Boost Converter is a very popular module. While it has a decent range of adjustments (0.5-30V and 0-4A), the output power is underwhelming (only 35W without any additional cooling). I was looking for a regulated DC power supply in a similar form factor as the ZK-4KX and found some interesting models. One of them is the XY5008L Adjustable DC Power Supply. Its capabilities include 0-50V, 0-8A, and importantly, power rating of 400W.
The main difference between ZK-4KX and XY5008L (apart from the obvious voltage, current, and power ratings) is that the ZK-4KX is a Buck-Boost Converter while the XY5008L is only a Buck Converter.
I have been using this power supply regularly for charging batteries and other minor projects. In this XY5008L Adjustable DC Power Supply Review, I would like to share my experiences of using this product.
What’s in the Box?
I bought the XY5008L DC Power Supply from a new platform (at least for me) known as SUNSKY. The listing had two options: barebones XY5008L Module and XY5008L module with a case. What caught my attention regarding the case is that it comes with a multi-input board that allows you to power the unit from one of the following: XT60, DC Barrel Jack, USB-C (with support for 20V USB-PD Triggering), and screw terminals.
The ability to connect a USB-PD Power Adapter without any external USB-PD triggering modules made me go with the case option.
That said, when the package arrived, I was prepared to assemble all the things in the case. Surprisingly, the product came pre-assembled and ready to operate. To show all the parts that went inside the case, I unscrewed the rear cover and here’s a look inside.
I will talk about the main XY5008L Module, the add-on power supply board, and the case in the next section.
Design of XY5008L DC Power Supply
Some of you might purchase only the XY5008L Power Supply while some (like myself) would be more interested in the complete kit. So, I will explain the design aspects of the main power supply module as well as the accessory kit.
XY5008L DC Power Supply
If you are familiar with the ZK-4KX module (or other similar power supplies), then the overall design of the XY5008L power supply feels almost identical. The front side of the main XY5008L Power Supply Module has a custom LCD, a Rotary Encoder (with click function), and a push button. These two (rotary encoder and the push button) are responsible for all the navigation and control operations.
The rear of the unit has four pluggable terminals for input and output connections (VIN+, VIN-, OUT+, and OUT-).
I have dismantled the entire power supply and here’s some of the interesting bits. The XY5008L Power Supply Module consists of two PCBs and both of them are connected through two sets of PCB headers. A good thing about these headers is that one is slightly offset from the other. So, even if you disconnect the two PCBs, you can easily connect them as they go only one way.
The PCB with the IO Panel is likely the main control board. It has a Nuvoton MS51FB9AE controller, which is an 8051-based Microcontroller and personally speaking, I love 8051. For LCD, they used a Holtek HT1612B LCD Driver (possibly a knockoff). There is an XLSEMI XL7005A Buck Converter (this will probably take the external input voltage and step it down to power the board). For 3.3V supply, the board has M5433B Regulator IC.
Coming to the second PCB, it handles all the power-related stuff. There are a lot of components on this board (power MOSFETs, diodes, current sensing resistors, OP-Amps, inductor, switching element, cooling fan, and more).
Very clever usage of space with vertically-stacked PCBs.
Case
The machined-aluminum case of XY5008L is very well-made. Some corners and edges are extremely sharp. I wish they had designed the case with an angled-front so that viewing the display and controlling the unit would be much easier. There are no rubber feet so it won’t stay in place while you use the controls. I might add some rubber feet later.
The case has some vents for the air to escape (or enter). Also, there are two color-coded banana jack connections on the front of the case.
Add-on Input Power Board
Last but not least, there is the input power board that is attached to the rear plate of the case. To be honest, I expected it to have a simple design that allows inputs from different types of connector. Surprisingly, it is much more complex than that. For starters, it has an ARM Cortex-M0 MCU from an unknown manufacturer (HK32F030MF4P6). There is a Buck Converter (XL7005A) and a Voltage Regulator (AMS1117 3.3) for powering the board and the fan.
Yes. In addition to the fan on the XY5008L Module, there is another fan at the rear of the case. We will see the thermal performance of the unit with some images from a thermal camera.
They scrapped the name of the USB-PD Trigger IC but based on the layout and connections, I think it is the FS312 USB Type-C Fast Charge Sniffer IC. The 180KΩ from Pin 7 is a dead give away. Refer to the datasheet of FS312 IC to understand the importance of this resistor.
If that is the case, then I don’t see the purpose of the MCU. If the job of the MCU is to just monitor the temperature (there is a thermistor near the MCU) and turn the cooling fan on or off, then it is definitely an overkill.
You can see different connectors on the PCB for providing input. Here’s an image of the rear of the fully-assembled unit with all the inputs and a fan.
The empty holes are meant for us to add any additional input interfaces.
User Interface and Controls
As I said before, the UI part of the XY5008L Buck Converter consists of a custom LCD, a rotary encoder, and a push button. To demonstrate the basic navigation and controls, I connected a 100W USB-PD Adapter using a USB C-to-C cable to the back of the unit. We can connect only one input at any time.
As soon as I switched on the power supply, it came to life and displayed the set voltage and current. On the left of the display, it says OFF and SET. This indicates that the output is off and you can set the values.
Basic Adjustments
Before you set the values of output voltage and current limit, make sure that the output is off. To set the output voltage, short press the rotary encoder button. The least significant digit and the ‘CV’ symbol starts blinking. You can then turn the rotary encoder to set the value. Click the rotary button to move up the decimal places (and circle back).
It will wait for three seconds after you set the value and if there is further input, then the device automatically sets that value as the output.
Coming to the output current limit, press and hold the rotary encoder button for about a second. The least significant digit of the current limit value and ‘CC’ symbol starts to blink. Adjusting the current limit is the same: while it is blinking, turn the rotary encoder to change values or short press the rotary encoder button to switch between decimal places.
Again, the value will be set automatically after waiting for three seconds from the last user input.
Once you properly set the output voltage and current limits, short press the ON/OFF button to turn the output on (or off, if it is on).
With the output turned on, you can long press the ON/OFF button (for about two seconds) to display the input voltage. Repeat this step to bring back the output voltage on to the display.
If you turn the rotary encoder while the output is on, you can change the bottom part of the LCD (that usually shows the current) to display Power (W), Amp-Hour Rating (Ah), Energy Rating (Wh), and the duration for which the output is on (h).
That’s it for the basic controls. I’ll talk more about other settings in the next section.
Settings
With the output off, long press the rotary encoder button (for about 3 seconds) to bring-up the Settings interface. And there are a lot of parameters to play with. Here’s a brief overview of the settings page.
The first parameter you get after entering the settings menu is the Input Low Voltage Protection (LVP). By default it is at 4.8V. You can change by rotating the encoder. There is no confirm or OK button. If you feel you’ve set the proper value, you can either go to the next parameter or exit the settings (by long pressing the rotary encoder for about 3 seconds).
Short press the rotary encoder to move to the next parameter, which is the Output Over Voltage Protection (OVP). The default value is 55V.
Here are other parameters in the order they appear:
- OCP: Output Over Current Protection (default is 8.2A).
- OPP: Output Over Power Protection (default is 450W).
- OAH: Maximum Amp-Hour (Ah) Capacity.
- OPH: Maximum Energy or Watt-Hour (Wh) Rating.
- OHP: Maximum Operating Time.
- CV: Default parameter that can be set when you single click the rotary encoder. You can switch between ‘CV’ and ‘CC’ by rotating the encoder.
- OFF: Power On State of the Output. OFF – Output is off after boot, ON – Output is on after boot.
While most of these parameters are simple and straightforward, there’s something interesting with OAH, OPH, and OHP. So I decided to create a separate section for these parameters.
OAH, OPH, and OHP
With OAH, you can set the maximum capacity (Ah) the power supply delivers. When you get the OAH while in the ‘Settings’ page, you can activate or deactivate it by short pressing the ON/OFF button (—- means disabled). If you long press the ON/OFF button, you can switch the range of the value (9.999Ah, 99.99Ah, 999.9Ah, or 9999Ah).
In case you set the maximum capacity value, the power supply will automatically shutdown after it reaches that capacity (and flashes OAH on the LCD).
The operation of the OPH or Maximum Energy Rating parameter is very similar. Instead of Ah the values are now in Wh.
In case of OHP i.e., Maximum Run Time, things are slightly different. If you set a value in the OHP, then the power supply uses it as a countdown timer. Once the timer becomes zero, the power supply shuts down and flashes OHP. You can enable or disable all the three parameters.
If you disable these parameters, then the unit will record the capacity, energy, and run time values normally.
Performance
To test the XY5008L Regulated Power Supply, I connected a 100W USB-PD Adapter. I know this is a 400W power supply capable of supplying up to 50V and 8A. However, in order to test those values, I would need a 60V 10A power supply (to give some breathing room). Sadly, I don’t have any high voltage SMPS units. This is always a problem with any high-wattage DC-to-DC Power Supply Units.
I was planning to use this device with a 100W USB-PD adapter anyhow. So, all the performance numbers I explore are associated with that as the input.
As Regulated Power Supply
For the first test, I connected the XY5008L Constant Current, Constant Voltage DC Power Supply Unit to a simple electronic load. I set the output voltage to 18V and without any load, the meter is showing bang on 18V at its input.
When I switched the load on, the voltage was fine until the current was around 2A (hovering around 17.8V). However, when I set the current to 4.3A (I set the limit to 4.5A), the voltage dropped to 17.3V. You have to ignore the readings on the load as they are not that accurate.
Speaking of accuracy, I connected a multimeter to check if the value of the current displayed on the screen is correct or not. And to my surprise, the value is very accurate.
This is important if you plan to use such power supplies to charge batteries, which I am about to do next. Before that, I would like to say that do not change the values of output voltage or current while the output is on. The unit will freeze (while still functioning) and you have to reboot the device.
To Charge Batteries
If you read my previous product reviews, you might know that I have a bunch of 18650 batteries (some good, some garbage). I built a basic 3S1P module with a 10A BMS using cells with 10C Rating (just a testing prototype, I will properly create a proper battery pack later).
First, I discharged the battery down to 10V (ballpark). Then I set the output voltage to 12.6V and the current limit to 1A on the XY5008L Module. Since I was using the power supply unit to charge a battery, it should automatically operate in Constant Current mode (at least in the beginning). After I connected the output of the power supply to the battery, and turned the output on, it immediately went to Constant Current (CC) mode as expected.
I read some users mentioning they couldn’t charge their batteries even when they set all the parameters correctly. After searching, I found out that you might have to set the Maximum Capacity Value (OAH) in the settings interface. You can set it to the highest possible value and leave it.
Even this time, both the voltage and current values are very accurate. Here you can see that I connected a multimeter to capture the current and the reading is spot on 1A.
You have to be very careful when charging Lithium-Ion Batteries with such power supply modules as they do not automatically shut off once the battery is full. The BMS of the battery plays an important role in protecting the batteries from overcharging (among other things). However, if you don’t switch off the power supply, you might put it in a float charge situation (which is not ideal, for li-ion batteries).
Be very careful when connecting the battery terminals to the output port. Do not connect them in reverse.
Thermal Performance
I know that I haven’t pushed the XY5008L Step Down Power supply to nowhere near its limits. Nonetheless, I took some thermal images when I connected the power supply to the electronic load that is drawing 18V and 4.3A, which is close to 78W.
After running the unit in this condition for more than 30-minutes, the hottest part was the heatsink below the cooling fan and it was only 45.6℃. Rest of the components on the board are much cooler. Based on this, I would like to think that even if you push the power supply, say above 200W, the temperatures will be reasonable.
The cooling fan sucks air from outside and pushes it towards the heatsink. On the other hand, the case fan sucks air from the inside of the case and blows it outwards. The internal fan comes on automatically based on either the temperature or the current draw.
Out of curiosity, I also checked the temperature of the add-on board i.e., the multi-input board at the rear of the case.
This is very interesting. The two diodes, just below the USB-C Port, are very hot, about 64℃.
Other Features
If you long press the rotary encoder button for about five seconds, you can lock the device. This way, you can prevent any accidental adjustments of voltage or current. You can unlock the device by once again pressing and holding the rotary encoder button for five seconds.
I already spoke about different protections offered by this device. Input Low Voltage Protection (LVP), Output Over Voltage Protection (OVP), and Over Power Protection (OPP) are software protections. When it comes to hardware protection, the power supply has Input Reverse Polarity Protection and Output Short-circuit Protection.
Specifications
- Input voltage: DC 6.0~55V (Minimum Input Voltage 5.5V, Maximum Input Voltage 60V)
- Output Voltage: DC 0.0V~50V
- Output Current: 0.000A~8.100A
- Output Power: 0-400W
- Output Ripple: VPP 150mV
- Voltage Resolution: 0.01V
- Current Resolution: 0.001A
Price
I bought the XY5008L Regulated Power Supply with the case for ₹2,200 (about $26) including shipping. If you want only the power supply module without any case, then it will cost you $13 (approx.). It is much more costly than the popular ZK-4KX Power Supply. However, the specs are also significantly better.
Generally speaking, DC to DC Converters as main power supplies for electronics-related work do not make that much sense. You will always need a proper power supply to pair with them. That said, for special applications (like charging batteries), you can always use them, if you know what you are doing.
Conclusion
Overall, I really liked this tiny DC-to-DC Step Down Converter Module. It is relatively a high-power unit and can work in Constant Voltage (CV) or Constant Current (CC) modes. Personally, I purchased the combo-kit that includes a machined aluminum case with provision for connecting multiple types of inputs (USB-PD integration is the selling point for me).
Protection wise, the unit has a combination of software limits and hardware circuitry. If you are low on budget and looking for an entry-level regulated power supply, then the XY5008L is a decent one to begin with. I have many more such DC-to-DC converters and am planning to test them very soon.