A while ago, [Skippy] bought a cheap knock-off of the Apple USB mains charger from an AliExpress seller, for the British low, low price of 89p. Normally we’d give you a dollar conversion, but since that’s coincidentally the price of the basic McDonalds hambuger in the UK we’ll go with the hamburger as a unit of conversion. And as any self-respecting hacker would, he subjected it to a teardown and gave it a few tests.
Surprisingly though its pins were a little long it was just within the BS1363 pin spacing specification, probably due to its external dimensions copying the Apple original. The emissions test he performed might surprise readers, as it gave the little device its first pass. Radiated RF emissions were well below the test threshold, a welcome sight for anyone who has had to test a device. Sadly the same could not be said for conducted emissions, and it was happily spraying RF to all and sundry from its connections.
Taking a look inside revealed the usual litany of frightening safety fails. There was no insulation between the mains pins and the circuit board, and a secondary capacitor was even touching one of the pins. Meanwhile another capacitor connecting both sides of the circuit was not of the required Y rating. These and a raft of others make the device illegal for sale in Europe without further tests, but to give some numbers to it all he subjected it to a screen test applying 600 VAC common mode to its pins and checking for leakage current through the device. This it failed, and indeed it did not recover from the test.
So in this case, the price of a hamburger definitely does not get you an Apple, nor even does it get you an equivalent. But of course, you knew that, because we’ve talked about fake Apple chargers and power supplies many times before.
https://skippy.org.uk/what-does-89p-geta-you-autopsy-of-a-chinese-phone-charger/: 404…
I’m not sure which is more likely to kill me…
Pick your poison.
The problem is that 99% of these uber cheap USB chargers coming from China are RF spewing deathtraps like this. This one has a bonus of being a fake Apple charger but you will find the same circuitry with minor variations and more or less egregious safety issues in most of these junkers. Even the ones sold at big name brick & mortar stores, unfortunately!
Saving money on mains power supplies is pretty foolish – that doesn’t mean one has to buy an overpriced Apple one but there are plenty of decent ones that are UL or TUV certified, for example (i.e. someone has actually inspected & tested them, CE mark *doesn’t require any testing whatsoever*!)
No to mention the “China export” mark
https://en.wikipedia.org/wiki/CE_marking#China_Export
Though how true this is, is debatable
Article URL changed to https://skippy.org.uk/what-does-89p-get-you-autopsy-of-a-chinese-phone-charger/
Thanks, seems the author moved it on their site while it was in our queue.
There was an extra a in the original link to the article; I have added the url with an extra a to a redirect, so now both options should now work :)
The page linked to has disappeared!
moved to https://skippy.org.uk/what-does-89p-get-you-autopsy-of-a-chinese-phone-charger/ apparently
Here’s an alternative read from 3y ago
http://www.righto.com/2016/09/why-you-shouldnt-use-cheap-macbook.html
Thanks, seems it moved on the author’s site while it was in our queue.
The charger of portable death
There is a site that tests batteries, chargers and powerbanks ( https://lygte-info.dk/ ) and most of those ultracheap chargers are deathtraps. HV/LV insulation is almost always below safe specs, sometimes insulation is prone to melting, plastic is usually not flame-safe … And filtering is non-exsistant while noise is measured in hundreds of milivolts. You can buy original for 30 bucks, good quality 3rd party for 15 bucks or complete crap for 2-5 bucks.
The BOM for a safe charger is only around $2. It may take a bit of searching to find a genuine Samsung or LG charger for under $5, but they are out there.
For a while, Poundland in the UK did £1 5W USB chargers that were supposedly OK, though they were rather bigger than the Apple ones. Trying to cram everything into such a small form factor whilst cutting costs to the minimum seems to spell sure doom.
I think Clive knows a song about this, don’t you?
https://www.youtube.com/watch?v=ioAq7PI1Uwg
“I would gladly fry on Tuesday for a hamburger today.” ~~~ Some Wimpy Apple user that spent the same on an “apple” charger as they would a hamburger…
I use cheap charger deliberately for one reason: I can not disable fast charging on original charger and fast charging is something that I almost never need and it makes my battery overheat and live shorter. And about quality – I know it does not tell much but simple test of short-circuiting charger and testing if it will come back and doesn’t produce higher voltage peak tells that it isn’t the worst crap.
just cut the data wires, th estandard for fast charging is data wires shorted
I believe the worst thing about these pieces of Chinese junk is that the general public knows nothing of the dangers and the regulators seem oblivious to the dangers of the ones that do make it to the mainstream markets. Doesn’t matter if it’s a petrol/gas station, the local supermarket or convenience store… It’s cheap, so it sells, In the States, these things can pop up with counterfeit markings, and I have no doubt that happens in other markets as well.
So what happens if one of these guys burns your house down? I’ve wondered about this. You can buy power outlets from Amazon that claim they are UL listed but there’s no actual listing number to be found. Does Amazon push off the blame to the seller if your house burns down? Are consumers truly responsible? Most of my friends are college educated, some are engineers and such, don’t even know what a UL listing is and I’m for sure my mother doesn’t know either. Is there anything being done about this or is it really not a problem? (I’m not expecting you [Will] to know, just asking anyone that zips by)
Safety, as a physics and chemistry-based engineering discipline, has long been ignored and shunned by the ‘hacker’ community. Understand that it is not cool, not to mention frustrating, to hear people say that your wondrous creation may not be safe. And members of IEEE Product Safety Engineering and EMC societies talk about this every time more than two compliance engineers gather in the same spot.
But we are all grown up and haired over – so let us not ignore accredited safety and EMC engineers when they offer a suggestion or two for your magnificent design. And yes, I have submitted articles to HAD, and I do understand why they were ignored. It is time for the HAD writers themselves to continue, at frequent and regular intervals, with the work started by Anool Mahidharia and others.
I suspect, they’ll pass the responsibility to the distributor or manufacturer. If they know the issue, they’ll fall back on plausible deniability. Most resellers don’t look past it’s cheap and it sells for a profit. I’m also not aware of, here in the States, anybody that has taken upon themselves or a family member to sue for the experience of fatal or near fatal shocks or fires in spite of how law-suit happy Americans are.
Here’s a couple of links to another site that has also looked at these things in the States:
https://www.tomshardware.com/picturestory/803-apple-5w-adapter-knock-offs-colorful-a1265-tear-down.html
https://www.tomshardware.com/picturestory/821-a1265-usb-charger-tear-down.html
GET IT write Tim apple it’s spelled hamberder
“applying 600 VAC common mode to its pins and checking for leakage current through the device”
What is the specific test method being cited and used? Touch current testing is typically done at 110% of rated mains voltage. If you are referring to di-electric withstand, then the test level is typically 3kV, and uncontrolled leakage current or breakdown of galvanic isolation determines pass/fail.
references
1. IEC/EN/ANSI 61010-1, annex A,
2. EN/ANSI 60950-1, section 2.5, annex D
3. EN/ANSI 60065, annex D
3. IEC/ANSI/EN 62368-1, clauses 2 and 5
4. IEC 60990
Note: standards based on IEC609950-x and IEC60065 should be considered deprecated.
Ok, re-read the Skippy article – some stuff was lost in translation to British to American. Perhaps it was intended to say that that, during the di-electric withstand test (‘hi-pot’), that the unit failed at 600V. But 1mA would seem to be an unusually low limit setting for this test.
For those interested, for hi-pot, the test voltage is linearly increased (montonic) to the test level (3kV) and then held at the test level for a certain period. during the voltage ramp or the test dwell periods, there can be no uncontrolled flow of current and insulators cannot arc or otherwise fail. Depending on the equipment and the scoped standard(s), I have typically set the current limit for 125% of the calculated leakage at the peak test voltage. For stand-alone transformers, I have typically set the current limit to 1mA or less. But for power supplies, limits are seldom less than 5mA.
Here is a video of a different EUT undergoing hi-pot test: https://skippy.org.uk/5v-acdc-converter-switch-power-supply-module-3w-700ma-industrial-voltage-regulators/
I have a few diffrent things on my site that I have subjected to EMC and LVD assessment over the last few years,