Safe In-Wall AC to DC Transformers??

[ferro]

@Pete357 said in Safe In-Wall AC to DC Transformers??:

Please can somebody more experienced with HLKs recommend really reliable source where to buy the right modules?

To be sure you get genuine module buy it directly from the vendor:
http://www.hlktech.net/product.php?CateId=10

[Pete357]

@ferro Thank you, didnt know they have own eshop. I should have been looking for it before.
I suggest to put this link into MySensors Store instead of that ebay link, for others looking where to buy it and not to make the same mistake as I did.

Thanks
Pete

[Nca78]

Very ugly modules indeed, I'm not familiar with ebay but you should have some sort of buyer protection ?
I could easily get money back on Aliexpress with mines that were looking better, so on ebay it should not be a problem.

[dbemowsk]

@Pete357 I had an issue with some modules that I bought that were not packed well. When they arrived, I had one or two that had at least one pin bent nearly all the way over. Some had case damage that was slight, but still usable. I contacted the seller and got half my money back. I tested all the modules and they all functioned properly. I use MOVs and fuses on the input power, so I figure I should be pretty protected in the event of a failure. I am not pushing them anywhere near the limits either. Do what you feel is necessary for your case though.

[hek]

Ok, removed the ebay link from the buying guide. If someone finds an alternative ebay seller with genuine modules, let me know.

[dbemowsk]

Sorry, I didn't mean to imply that I bought them from that link. Never the less, it sounds like those are not genuine.

[matz]

Hi Guys,

What a huge topic :)

Has anyone tested this 3,2 $ module ? Do you think it is safe to put it in the wall socket ?

AC-DC Isolated AC 110V / 220V To DC 5V 600mA Constant Voltage Switch Power Supply Converter Module

In the comments on guy disassembled it :

Regards

Matz

[korttoma]

@matz why not use the HLK-PM01 that is known to be safe?

http://www.hlktech.net/product_detail.php?ProId=54

[matz]

Hi

I understood that the HLK-PM01 can not be directly used out of the box, and that we need to solder it to a pcb with Varistor etc. but i may be wrong

I dont have the skills to do that for something potentially dangerous. I need something that can be used out of the box and connect it directly to a wemos mini d1

[Nca78]

@matz said in Safe In-Wall AC to DC Transformers??:

Hi

I understood that the HLK-PM01 can not be directly used out of the box, and that we need to solder it to a pcb with Varistor etc. but i may be wrong

I dont have the skills to do that for something potentially dangerous. I need something that can be used out of the box and connect it directly to a wemos mini d1

But from the pictures, it doesn't look like this is safer than an HLK... much more like the opposite.

They didn't even bother to make slots to increase creepage, while high voltage and low voltage sides are clearly way too close. You can compare with layout on the HLK here, there's way more distance between the too sides of the board, but still they added a wide slot under the optocoupler (on the side, next to R6) to increase creepage.
http://lygte-info.dk/pic/USB PS/P01 Hi-Link HLK-PM01/DSC_1454a.jpg

There's also no filling in the enclosure for extra isolation, to even the heat generated and to protect components from environmental pollution. It should be ok for dust because opening is small but not at all for humidity...

If you look at the product description of the exact same power supply (without the box) on AliExpress you can see they advise much more extra components than for the HLK: input fuse and at the output: RC filter, extra ceramic capacitor for high frequency noise, TVS diode and Y2 safety capacitor.
https://www.aliexpress.com/store/product/1PCS-SANMIN-AC220V-to-DC3-3V-600MA-3W-Power-supply-Isolated-switching-power-supply-module-220V/923896_32799372973.html

If you don't trust an HLK with extra safety (fuse + MOV) in your wall you shouldn't trust that thing. It doesn't seem to have much consideration for high/low voltage sides isolation and it's just been put in a plastic box like it is a complete and safe power supply, while the safety components advised by the original maker were not added...

[matz]

@nca78

Thanks a lot for this complete answer. I understand that i should use HLK but put in on a PCB and add varistor and fuse like described in the edit of the first post. The problem is that I really don't know a lot about eletronic. For arduino things in 5v or 3,3v I have no problem to try to do myself, in order to learn, but for 220v i prefer to use a finished product... Is there exist somewhere a finished product with the HLK and all necessary pieces, ready to wire to the 220 v and to the arduino/nodemcu ?

Regards

Matz

[sundberg84]

@matz I have made a breakout board. But using this and the pre-defined components you are on the right track. It's all easy to solder components (temp fuse can be a little tricky) . I don't have much time to source and solder assembled projects but have a look and you might get some ideas.

https://www.openhardware.io/view/504/HLK-PM01-breakout-board

[matz]

@sundberg84

Thanks a lot it is very useful and i'm sure i can do it myself with tour board already designed.

Juste one question : what are the sizes of the bard in all 3 dimensions ? I need to be sure it will fit in the wall where i need to put it before ordering the components. I could not find these info on the page you sent me.

[sundberg84]

@matz hmm, traveling now so can't measure but 50 long I'm sure. It's probably 35-40mm wide.

[matz]

@sundberg84
Quite small, so.

In a link above i've seen a review of the HLK from one guy who seems to know about electronics.

He recommends using the VIGORTRONIX VTX-214-005-105 AC/DC PCB Mount Power Supply . He said "for only a few quid more you win a switch mode PSU that stands a chance of not requiring external components to pass Class B!"

Anyone here has tested the Vigortronix ? Is it better than HLK ?

[dbemowsk]

@matz Never tried the Vigortronix, but I tried some from a company called Recom that were pretty good. Quite a bit higher in price though too.

[matz]

@dbemowsk
Ok thanks. I will try to build the sundberg84 board but i will try also to find a case built with a 3D printer as i prefer not to let all this stuff unprotected in case someone else than me in the futur open the wall socket

[dbemowsk]

@matz Now that I have had my 3D printer for a year, I don't know why I didn't get one sooner. FOr these very reasons. If I need a case for something, I cad it out and make it.

[matz]

@dbemowsk
I'm planning to buy one, i'm sure there are plenty usage of it (sorry for my bad english i'm french :))

Concerning the PSU, one question : we could just disasemble an iphone charger, the small one is 5cm x 1,5cm x 3 cm, and reuse it in the wall. IMHO it is more safe than build ourselves a PSU. Has anybody tried this ?

[dbemowsk]

@matz Why disassemble it other than to solder on some external power wires. Leave the original protection in place and you shouldn't have to worry about shorting anything out.