Well, I must say, I am very happy with the result. Thanks for the testing.
So, I am already planning to use it in a number of devices. To avoid too high temperatures in confined boxes, it might be a good idea to glue a temperature fuse to it and wire it in series with the live mains wire. When the temperature rises above, lets say 75 degrees celsius, the fuse breaks down.
Looks very nice, but you cannot use it for sensors or actuators that can be touched by hand and do not comply with the insulation standards, since parts of it will be connected to mains.
@petewill I think this is a wise decision.
I liked the discussion on this thread, so I have to thank you too.
Now it is waiting time. Waiting until the hlk-s arrive at the lab of the test guy.
My Chinese friend said, the package is on its way.
@rvendrame said:
@Atomfire said:
Not a big fan of soldering SMD components and I cannot find standard components, how essential is the 2nd fuse and varistor on the 5v side?
We are trying to make it as safer as possible... Assuming such modules will stay in a wall box, very close to wires and/or other potential fireable materials, we should try to mitigate risks as much as possible.
As I mentioned above --- This is DIY, also means 'risk it yourself'. Don't tell your insurance company
That is why I prefer to use fuses that blow, like the ones I mentioned earlier.
The resettable fuses also get warm. Can't wait for the package from Conrad to arrive. I am dying to do some further testing.
With respect to the brave HLK ... it is on for some three days and it is stable.
Short update ... yesterday I asked or Chinese friends from Alie to send a HLK module to our test friend.
I also did an insulation test with 1000 Volt. The test shows more than 1000 MOhm between ac and dc. So far so good.
@aproxx This is a different kind of notation, but when I look the device up in de Bourns catalog, I see it is rated for 250 Vac. That should be good.
@aproxx The only varistor I see in your list is 5.5 Volt.
@aproxx I would say that the 50 mA fuse is too weak. The HLK draws between 0.1 and 0.2 Amp and can surge 10 Amp. So, I think the 1A version is good for both situations input and output. The varistor is only good for the output.
One thing to consider though. This is also chinese stuff ... is it really safe or are we introducing a new problem? 
@rvendrame said:
@Moshe-Livne said:
@rvendrame Considering cost of postage and logistics involved it would probably be cheapest to just order two units from Ali to him? its 8$ including shipping if i remember correctly
Yes, it makes all sense. The only downside is that if we buy all at same time probably he will get all from the same lot, but in my opinion it by far doesn't invalidate the testing.
So, myself, @Bertb , @Didi = 3 PSUs, better than 2. I will share with you both the ship-to address ok? Thanks a lot!
I managed to borrow a Megger (high voltage resistance measurement device). This weekend I will test the insulation of the MLK.
The only drawback is that the Megger reaches to 1000 Volt.
@rvendrame said:
Hey guys, I wrote to the owner of the site suggested by @Moshe-Livne. He replied saying that he can test the HLK.
He mentioned that usually he takes at least two units (so if one burn he can continue the testing). I will send one from my lot, perhaps we have a brave guy to gave up one more? (a sacrifice of few to save many )
Let me know and I will share the address via PM (Denmark).
I am in for this.
Something went wrong with uploading the file, I think.
Herewith a new schematic with a suggested bill of material.
It is highly experimental still, but I ordered the components yesterday.
I am specially interested in working with the PTC fuse.
I hope the proposed circuit works for you. Please keep the maximim continuous output power in mind. It is only 3 Watts (600 mA).
In some cases you might need to add C1's (rule of thump 1 per chip or chip VCC) and/or need to increase the value of C2. This depends on the fluctuations in the power demand.
With the proposed values for C1 and C2, the ripple remained below 50 mV at 500 mA.
Also keep in mind that a remaining oscillation frequency residue appears in the output of some 60kHz.. If capacitors are not able to filter that out, a small coil might be needed.
Well it is experimenting that makes this fun, isn't it?
@petewill The schematic is just a simple draft. It can be seen with IE.
@Atomfire I will come back to that tomorrow.
@ThinkPad Well its your desk, so its fine with me.
Is there a way to get your address without shouting it from the rooftops?
@ThinkPad I am not sure it is still safe to operate.
Just to be sure everybody understands the schematic, hereunder a schematic.
I am not a fan of blowing mains fuses ...
The specs of the unit states that it resilient to high voltages. I tested it with 250 VDC across input and output.
As stated before in this threat, the specs are ok, it only lacks the stamps.
From what I have seen so far, the module is good for me.
From the specs:
4.Safety CharacteristicsοΌ
4.1Products designed to meet UL, CE safety certification requirements.
4.2Safety and electromagnetic compatibility
Designed with the input of 0.5A UL certified insurance;
PCB board using double-sided copper clad plate production, material for the 94-V0 fire rating level;
Safety standards: Compliance with UL1012, EN60950, UL60950
Insulation voltage: I / P-O / P: 2500VAC
Insulation resistance :I / PO / P> 100M Ohms / 500VDC 25 β 70% RH
Conduction and radiation :comply with EN55011, EN55022 (CISPR22)
Electrostatic discharge :IEC / EN 61000-4-2 level 4 8kV / 15kV
RF radiation Immunity: IEC / EN 61000-4-3 See Application Note
4.3 Temperature safety design
At room temperature,the capacitors of this power , the inner surface of the main converter maximum temperature does not exceed 90 β;
Shell maximum surface temperature does not exceed 60 β
At 535 mA, the temperature stabilizes at 39.81c /F 103.66
My initial safety is always toward the biggest danger ... mains in this case.
For the secondary part a simple semiconductor fuse and a zener (transzorb) will do.
Now for the million dollar question ... would I mount a HLK in a flush box?
Well ... when equipped with varistor and fuse and with the load on the safe side ...
Yes, I would.
I did not finish the automated power tester, but I put an HLK with a DS18B20 temp sensor in a closed flush box(is that the English word for the box in the wall, used for domestic wiring?).
A simple resistor acts as a load and draws a 800 mA from the power supply. That is 33% more than the max continuous value. Voltage across the leads is 4.96. That is 5.08 without load. Not too bad. At 600 mA (100% load) the voltage is also 5.00.
The Dallas says that the surface temperature at the HLK is 48.19 c ( F: 118.74).
Also do not forget to mount adequate capacitors to reduce ripple.
@petewill and @rvendrame ... Every country has directives regarding flammability. I cannot say which one is valid. I have seen some testing in the past. They put a burner under the device under test and waited to see what happened after removal of the source. In general (without any warranty whatsoever) when there are no flames or when they extinguish autonomic is good. If there is no hot material dripping from the DUT, that is also good. The test I carried out is described above. No dripping en self extinguishing. So I am satisfied.
Sorry, I cannot be more specific. I do not have the knowledge.
@rvendrame: yes the fuse in series in the mains live wire en the varistor in parallel with the primary side of the HLK.
With respect to the varistor ... see the sheet below:
Take a value that is well above the normal AC tension of your mains power, but below the max input voltage of the HLK. so in Netherlands 250 volts will do.
I do not totally agree with this. When I take a look at the example circuit and read the ovp text, I can only conclude that the output is protected, because the circuit seizes to work when VCC rises to high. Whatever happens to the input circuit, I don't know. Therefore I prefer a fuse and and a varistor.
Have a look at the tutorial link text
Observe the air gaps.
I also tried to incinerate the gum stuff that is inside the module with a cigaret lighter.
After a couple of seconds it starts to glow, then, after some 10 seconds, the material starts to burn. But this stops within some 20 seconds ofter removal of the lighter.
I made a film, but it is too large to upload.
I am not an expert on AC-DC converters, but I am quite impressed by the layout of the design.
The only thing that worries me is that I do not see how the OVP is created. On the other hand, this can be easily solved by adding a fuse and a ovp zener in the primary circuit.
@Moshe. Yes they are. I did not yet dug into that, but is that good news?
And I found the AP8012 chip inside. It has the following features:
_1286955514_oj99d4.pdf
Wait Mike, there is more ...
I sacrificed a device to the altar of success and opened it.
That was not very difficult. After scratching away some gum stuff the following was revealed.
I will try to remove the rest of the gum with acetone. I will also do some heat and burn tests.
This is quite funny to do 
Sorry for the language thing. I will try to get some tests in English in the future.
The tester used is designed for tests of medical equipment and this specific test proves that this specific HLK was safe. The problem is, however, that it does not prove anything with respect to the safety of other HLK's.
In the mean time, the same HLK is feeding a load of 730 mA. It's output voltage is 5.08 volts and the case temperature is Temp 46.81 Temp F: 116.26105.
@Didi. You are correct. I work in a hospital. I will try to setup the Fluke to English.
Well, here is the test file. I made it using test software named Ansur and a Fluke ESA640 tester in a Class II test setup.
The only problem is that some test results are in Dutch.
Last week I carried out an elektrical safety test on the HLK-PM01 to NEN 60101 (Dutch test for medical equipment) and it performed pretty well. I will try to post the file, after I removed some private information
Furthermore I am building a automated load tester that relates variable loads to output voltages and surface temperatures, based on an Arduino Nano.
Hi,
I am new here and decided to join this forum, because of this interesting discussion.
Some weeks back, I was looking for a cheap AC-DC converter and ran into the Hi-Link modules. The have very nice specs, but I discovered that there are no stamps to prove it.
I too plan to bring an offer to the gods of AC-DC, so I will build a module into a safe box and see what happens when I start annoying it.
I'd like to finish for now with a remark to rvendrame, if I may:
It is true that stone is very difficult to ignite, but fire and heat also melts the plastic coating of the elektric wires and this can lead to high currents that are just not high enough to blow the fuse in the mains fusebox and this can ultimately lead to fire elsewhere in your house.
Regards,
Bert
