i dont know what these ps are good for, are they employed for powering Apple ipads during a work day or for charging Apple liion cells in iphones during the night? never mind.
the 4 most expensive ps were the 4 best? i see :)
goobay .. i think it's German stuff (goobay.de).
Thanks for the superb review!!
The #1 in my test? I will recommend that you break it apart and throw it out, with 0.5 mm in isolation distance it is not something to have laying around.
On the one you linked to, try reading the text on the bottom of it, there it says 1A. It is probably just as unsafe and weak.
If you really want a small ps, buy the Apple one, it is safe.
Yet another quality review by HKJ! Been reading your reviews on chargers and batteries! Reviews are always packed with nice charts and high quality pictures!
Thanks HKJ!
Very interesting and useful, thanks a lot for the effort
I just received 1 of the 1.5a chargers today…and it is 1A. Thanks for the testing, great info!
As appreciated as your tests have been for me, this is the best.
So many of these cheap chargers… I feel like you’re driving a car steering me to the good stuff.
GREAT work HKJ!
Great review, very important safety facts!
Highly appreciated!
Insipred by this thread, I tore down one (failed) Xtar WP2 II power supply unit.
Since I’m no-pr0, I will post pics to another thread and let You guys decide “what it has eaten” :bigsmile:
Here is a link to tear down: Tear Down: Xtar WP2 II -power supply unit
Awesome review, thanks HKJ!
If you look at the myriad of PCBs out there in electronic devices the distances separating circuitry apart from disaster is likewise as these USB units. The point being is don’t get these type of things wet or for that matter any other similar device, nor mess around in there unless you know what you’re doing and you should be fine. Even if gaps somehow connected with the AC voltages involved the result would most likely be a fried connection, a strong smell, and a device that doesn’t work.
The tests here IMO would have more credence if the author subsequently bridged these gaps, submerged the units, or some similar test to see what actually happens if said gap was bridged. Think UL Labs testing.
IOW, overeaction IMO.
The safety standards says 4 mm distance in air, on a pcb it will be longer, except if it has a special isolating coating. This distance has two purposes, one is to withstand humidity and dirt, the other is to withstand transients on the mains.
I did not open the transformer, but it will probably also fail the safety standards on the cheap units.
Read this article from BBS, especially the bottom part, that is what can happen with the worst of these chargers.
What’s the gap safety spec if they did have it?
A UL Labs style torture test would be interesting. Do they catch on fire, go into electrocution mode, etc. IMO, any electrical device that’s abused whether by liquid, cord yanking, what have you, is potentially dangerous. The construction of the units claimed as being unsafe on the surface seems pretty robust. I don’t see dangling bare wires or particularly shoddy soldering IOW.
The safety standard is called IEC60950-1 and is implemented in many countries (including US). One important aspect of it is that any vital to safety isolation must be double thickness or two layers normal isolation. There is also different requirements in US and EU, because the mains voltage is different (110VAC vs. 230VAC).
For US indoor equipment with safety earth only needs 1 mm safety distance, without earth 2mm, in "Polluted degree 3" environment it is 2.6 mm and all these distances can be reduced if the factory does a high voltage test on equipment, before shipping.
The standard does list many other safety requirements, including detailed specifications on how solid the equipment must be.
IOW not three pronged like you typically see on most power tools? If they had it then the 1mm distance would be ok? I was also thinking about US and EU voltages and their respective different safety guidelines as you wrote the reply.
I think if we dissected most Chinese inexpensive electronic devices a good many of them would also fail under stringent wide safety criteria as well. 
As air distance yes, not on a pcb.
Because both EU and US uses the same safety standard, the differences are probably minor, and all equipment that can work on bot 110 and 230VAC, needs to use the larger distances.
I do believe that.
Thanks! Glad it was tested and found to be different from the Apple chargers. Hard to tell these days who builds what for whom and to what standards
I believe that big brand names are careful with the security, just imagine what it would do to Samsung or Apple if one of their charges killed a child!
Thanks for the reviews HKJ.
wondering about my computer’s USB ports now.
Excellent work, thank you.
Any plans to do car chargers/power supplies ?
:hopeful smiley:
Not at the current time.