Dodgy USB Chargers - Page 1
Forum section: electronics / general

author: labnet
author_rank: Contributor
timestamp: September 17, 2018, 03:53:33 am
content: Thought I would start a thread for dodgy USB chargers.You know, you buy the 'genuine' apple USB charger only to find its a chinese knockoff.I remember once buying a 12W apple charger and the 240v head plastic was slightly different to the case body. I took it apart, and lo and behold, craptastic creepages. The ebay seller replaces it. I take the replacement apart, and boom, different design and at least an attempt at creepage control but again a copy.I down vote them, and oh boy are they upset. No amount of explaining would convince them that what they were doing was illegal and potentially dangerous... no.. it was all about the one star review.My latest problem is with a Volans unit bought from retail in Australia. The end plate takes the full force of the PCB when unplugging the fig-8 power cable. The end plate has popped off on my unit, pulling the unrestrained PCB with it and exposing 240v direct to consumer in the process.Maybe Dave should go buy a whole heap of 'Genuine' chargers from ebay and check them out.

author: Raj
author_rank: Frequent Contributor
timestamp: September 17, 2018, 04:02:42 am
content: Brands aren't no better. My genuine made in India, motorola usb-c charger has started to give bearable amount of shock after 3 years of use (touching the shielding portion of the charger plug is enough to give you a shock).To make it worse, the whole phone's body is conductive.My hp printer's adapter, lacks a ground pin.touching any metal portion like usb port gives you a shock, Until you connect it to a grounded computer.My samsung monitor does the same thing too,if you touch vga plug,unless again, its connected to a computer.None of them trigger mains GFI.You know, when devices start to give you shock, it is really a good method to brain wash yourself to not use them.Meanwhile, My zte charger and motorola charger, age 6, works fine but both are rated for 600mA.They Really don't make things like they used to.

author: Raj
author_rank: Frequent Contributor
timestamp: September 17, 2018, 05:05:03 am
content: Quote from: blueskull on September 17, 2018, 04:10:37 amTrue, electricity is way worse when it has a direct path through flesh. I've given myself shock from 9v battery by accidentally pricking the wire into my fingerbut it's kinds strange,Hp printer has a ground pin, which is not connected anywhere at all.Why didn't they connect it to reduce the shock? Plus, Motorola charger didn't give a shock when it was brand new.

author: wraper
author_rank: Unknown
timestamp: September 17, 2018, 06:43:58 am
content: Quote from: Raj on September 17, 2018, 05:05:03 amBecause it's double insulated and does not need ground pin for operating safely. Then think about charger plug size and where it will be plugged, don't tell me fairy tales about all sockets in India to be grounded. Also without Y cap, touchscreen of the phone attached usually will stop operating properly, even if there was no purpose of passing EMC test.QuoteThen something has changed in how you used it. I guess at that time there were no metal objects with a path to ground anywhere around. Therefore there was no path for current to flow and you did not feel anything.

author: labnet
author_rank: Contributor
timestamp: September 17, 2018, 10:21:28 pm
content: What I find interesting, at least in the Australian context, is that as a business, I have to make sure I pass RCM. In fact we pulled a product because re-certifying ($10k+) was going to cost more than the profit than we made on that particular product.Yet, people can import products without RCM marks, and I'm sure most ebay sellers are bulk importing from China and reselling their gear without getting the local certifications.So either certification is a waste of time (because death rates/interference haven't gone up from the use of all this un-certified gear so we should scrap it), or the government should be doing a lot more policing of this area to make a level playing field for everyone.

author: Raj
author_rank: Frequent Contributor
timestamp: September 18, 2018, 04:47:18 am
content: Quote from: wraper on September 17, 2018, 06:43:58 amThe phone's body is metallic, so I would have noticed. Now I can't touch the phone while charging. Also, this means, it ain't double insulated.Also,nothing was done to the charger except for using it to charge the phone.So natural degradation pretty much.The touchscreen still works.I don't care since the phone was S#!t anyways, except for the battery life, camera and best kind of card tray.And about grounding India,My house has grounding ever since it was built. But it's becoming a must have since even corsair's (other companies too) computer power-supply electrifies the chassis of a computer, if ground is missing.My cousin had to get his house electricity grounded because of that, when he bought his first PC.Attached-photo of a goofy plug for hp printer's adapter.Notice how the wire contains only 2 conductors and no ground point at adapter side. Funny that they spent an extra buck on the metal of plug's ground pin.

author: wraper
author_rank: Unknown
timestamp: September 18, 2018, 07:40:38 am
content: Quote from: Raj on September 18, 2018, 04:47:18 amDo you understand that current won't flow unless there is current path? You can hold line wire under voltage and not feel anything if you don't touch anything else conductive (say standing bare foot on wet floor).QuoteSo you don't even know what double insulated means.

author: Raj
author_rank: Frequent Contributor
timestamp: September 18, 2018, 08:44:39 am
content: Quote from: wraper on September 18, 2018, 07:40:38 amDouble insulated means, every part of the circuit has 2 layers of insulation as separation from outside. Moto z play isn't double insulated. The whole body of the phone is connected to usb shielding and the ground of the whole circuitry inside.Also, charger was double insulated but it now has failed.You can feel it zapping you even with rubber flipflops on.And surely if it was made like this from day one, it would have zapped my in 2 years of heavy useThe fact remains that it has started to zap me and that wasn't the reason why I stopped using it.(I could have replaced the charger and continued)Also, there is 35 volts AC, from usb shielding to the ground with max current of 5uA

author: wraper
author_rank: Unknown
timestamp: September 18, 2018, 09:10:52 am
content: Quote from: Raj on September 18, 2018, 08:44:39 amYep, you completely don't understand what it means. Sure phone is not double insulated, the charger is.https://en.wikipedia.org/wiki/Appliance_classes#Class_IIQuoteQuoteLOL, and you call it failed insulation?. With Y cap between primary and secondary side you normally can measure half of the mains voltage and up to about 0.3mA leakage current. And it's completely normal and within spec.

author: stj
author_rank: Super Contributor
timestamp: September 19, 2018, 06:51:11 pm
content: so-called "safety caps" can and do go leaky with age - so do MOV'sif your getting more of a tingle than when it was new then the cap is probably starting to break down.

author: wraper
author_rank: Unknown
timestamp: September 19, 2018, 07:09:24 pm
content: Quote from: stj on September 19, 2018, 06:51:11 pmExcuse me butYcaps don't get leaky unless something extraordinary happens, and such product gets recalled. Also comparing them with MOVs is ridiculous, there is a good reason why MOV clamping voltage goes down with time.QuoteYou'll get tingle from almost anything if there is Y cap and current path through you. Also you may feel weird feeling when moving your fingers over metal surface even if there is no current path. Especially noticeable on laptops with metal case.

author: stj
author_rank: Super Contributor
timestamp: September 19, 2018, 08:28:55 pm
content: i'v been in the repair industry for a long time and replaced more than a few safety-rated caps that had gone leaky or just plain split in half and burned.it may be rare, but it happens.here is something to dwell on.if a cap is rated at 1KV and is sitting on a 240v line, how many times a day is it going to see over the rated voltage for a fraction of a cycle?i'm pretty sure test meters rated for mains must be spec'ed to survive 6KV spikes.

author: Wolfgang
author_rank: Super Contributor
timestamp: September 19, 2018, 08:32:43 pm
content: Hi,I must say, same experience. I hate them. They are unsafe, create a lot of illegal EMI and are simply junk.To get some RFI out of my ham shack, I killed them all. See here:https://electronicprojectsforfun.wordpress.com/power-supplies/a-quad-usb-power-supply-with-low-noise/

author: wraper
author_rank: Unknown
timestamp: September 19, 2018, 09:29:41 pm
content: Quote from: stj on September 19, 2018, 08:28:55 pmX capacitors sure do blow up, never seen Y cap failed. And if this happens it should be caused by something akin thunderstorm. You cannot buy Y cap rated for 1kV. For consumer electronics Y2 and sometimes Y1 capacitors are used.

author: Gyro
author_rank: Super Contributor
timestamp: September 19, 2018, 09:53:02 pm
content: I came across a couple of Rifa MP Y caps in anoldHP3310A Function generator after the X one did its characteristic meltdown. They hadn't failed but were showing the same characteristic package moisture cracking. Needless to say, they got retired!Those are the worst exception though. You're unlikely to come across anything other than Ceramic Y caps these days, certainly in new stuff.

author: wraper
author_rank: Unknown
timestamp: September 19, 2018, 11:01:49 pm
content: Quote from: Gyro on September 19, 2018, 09:53:02 pmYep, those are exceptional junk. Although I dod not came across those caps in Y variant. Normally Y caps are ceramic.

author: Raj
author_rank: Frequent Contributor
timestamp: September 21, 2018, 03:49:20 pm
content: Well I did had a problem distinguishing purpose from methodThe company should have thought of what if scenarios and should have designed the charger differently so as to not allow any leakages considering that the user is definitely gonna come in contact to it.Btw,No other phone charger, including those using Y caps that I've seen so far leaks current so high the one can feel it. Infact I trust my reputation on many of them. I often insert sony charges into my creations.

author: wraper
author_rank: Unknown
timestamp: September 21, 2018, 06:28:23 pm
content: Quote from: Raj on September 21, 2018, 03:49:20 pmExcuse me but 5uA leakage current is nothing. You'd have a very hard time finding a charger with so little leakage current. I think it does not even have Y cap at all, and all leakage happens through capacitance between windings in transformer. Or you did your measurements wrong.Yeah, and your measurements completely contradict your claims about feeling current leakage. And don't forget that all leakage through Y cap happens as AC through capacitance. It has nothing to do with quality of insulation.

author: stj
author_rank: Super Contributor
timestamp: September 22, 2018, 10:19:43 am
content: and inclusion of said cap violates the "double insulated" claim.it's "insulated" (sort of) by a single dialectric layer.

author: Gyro
author_rank: Super Contributor
timestamp: September 22, 2018, 10:39:37 am
content: Quote from: stj on September 22, 2018, 10:19:43 amIt's done by agency approved withstand voltage rating. You would specify Y1 cap (8kV withstand) for Class II. It's the same situation for the regulation feedback optoisolator....In Grounded chassis applications you typically use Y2 caps (~4kV), In Class II double insulated you use Y1 (8kV)The same situation with the PCB itself. For grounded chassis, mains to chassis clearance is 4mm, for Class II it's 8mm. Effectively two 4mm insulation gaps side by side. They don'thaveto be physical barriers (as long as the conductors can't move!).

author: TurboTom
author_rank: Super Contributor
timestamp: September 22, 2018, 12:45:46 pm
content: Well, this one is a good joke by itself. And you probably need a good insurance if you're going to use it. Wait a moment, got it as a feebie with the branding of a major international -- you guess it -- insurance company!So far, so good...No glue whatsoever, the plate with the wall plug prongs is just snapped in and it's so wobbly a five-year old could open itAdmittedly, it's tiny but do these components have to be cramped inside like this?Isolation clearance? What is it? It would be generous to say it's one millimeter. And even that's sprinkled with flux!Here's the one I like most -- a genuine press fit between the input smoothing electrolytic and the USB shielding can. Probably cannot get any better than this!If this company is still in business? They've got to have a good insurance...Obviously, I never plugged that one in. Maybe I'll check it with an insulation tester, just for fun. At least the micro USB cable that was included is useful since it includes the data lines unlike some of these super-cheap charging only cables...

author: Gyro
author_rank: Super Contributor
timestamp: September 22, 2018, 01:10:48 pm
content: That isby farthe worst I have seen in a long time! It's impossible to quantifyanyprimary-secondary isolation gap.The fact that they are a German based Insurance company is the topping on the cake! .... Oh no, sorry, the dry jointed negative lead on the output capacitor is probably in the running too.P.S. I am sorely tempted to sent Allianz a link to their blatant breach of CE regulations, and hence, EU law! [Edit: @TurboTom, how long ago did you get that thing? Any history? Presumably they've handed out these lethal items by the bucket load!]

author: wraper
author_rank: Unknown
timestamp: September 22, 2018, 01:14:03 pm
content: Quote from: TurboTom on September 22, 2018, 12:45:46 pmI would not consider it as anything good. Most likely it has hair thin strands in the wires which have so much resistance that phone will limit charging current because of a huge voltage drop. Also don't expect it to be shielded.

author: TurboTom
author_rank: Super Contributor
timestamp: September 22, 2018, 01:49:33 pm
content: My daughter won it at a tombola at this year's summer festivities at her school. All the items given away there had been donated by parents. I remember there were many of the USB power adapters. Only recently I got it in my hands again and opened it. I guess I better phone the school on monday and warn them about the adapters...I don't know when or if they had been actually distributed by Allianz or if they just stayed in some employee's home who eventually donated them to the tombola.Cheers,Thomas

author: madires
author_rank: Super Contributor
timestamp: September 22, 2018, 02:39:27 pm
content: No surprises there! Or what do you expect from an US$ 2.50 USB charger? Unfortunately a lot of gadget manufactures put one of the cheapies in the box. Same for the ubiquitous SMPSU wall warts for other electronics. But as a member of this wonderful electronics forum you should be able to perform a proper QC

author: wraper
author_rank: Unknown
timestamp: September 22, 2018, 02:55:08 pm
content: Quote from: madires on September 22, 2018, 02:39:27 pmThe issue with chargers is that you really cannot take them apart without damage. Of course really dodgy ones easily break apart so you could use it as a first test.

author: Raj
author_rank: Frequent Contributor
timestamp: September 22, 2018, 03:07:40 pm
content: I've even seen, some of them blowing up.One of them even had a capacitor that was under rated (4.7v) at output.Many of them don't fit any country's socket thus keep sparking away ruining itself overtime.And about y caps making screens go haywire. Chinese chargers do make my moto defy's screen nonfunctional when charging. But my galaxy s4, moto z, and chinese phones still function well while charging.

author: stj
author_rank: Super Contributor
timestamp: September 22, 2018, 05:13:30 pm
content: Quote from: madires on September 22, 2018, 02:39:27 pmthat's no excuse.

author: Gyro
author_rank: Super Contributor
timestamp: September 22, 2018, 06:11:37 pm
content: Quote from: TurboTom on September 22, 2018, 01:49:33 pmMight be an idea if school kids are involved, better safe than sorry. A bit delicate for the innocent well meaning parent involved though.I guess Allianz count as the importers in this case, so could find themselves on the wrong side of the law if an accident happens.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 22, 2018, 08:13:52 pm
content: Those promotional items are often sold from companies that essentially search for cheap ass parts and do the printing. So you can likely find those same type of USB charger with different names on top.So it might be a good idea to notify someone. At least with an insurer chances are they go after it. Otherwise there is also an official path with an EU warning list (RAPEX) for such items.

author: Gyro
author_rank: Super Contributor
timestamp: September 22, 2018, 09:21:23 pm
content: QuoteWell I bit the bullet and sent an email to their Investor relations department - the only non-phone contact I could find. It will be interesting to see what comes back. At least they can't deny knowledge of the issue now.QuoteI think that covers things enough for them to establish the facts for themselves. I don't know how you go about the RAPEX process, maybe you want to have a shot at that.Hopefully I've done the right thing - in all conscience, I wouldn't have felt comfortable doing anything else after seeing the photos.

author: labnet
author_rank: Contributor
timestamp: September 26, 2018, 10:58:47 pm
content: Your charger is not an isolated case. There are thousands of unique designs with hundreds of millions of chargers that would be non compliant with electrical safety and EMC.So I think the question we should be asking is: Is personal injury and property damage increasing because of this?In Australia, I'm only aware of one case where a woman was using her phone on a Chinese charger in the bath and was electrocuted.Are the creepage standards too tight? Probably not. Are they hard to comply with? Not really. Is conformity testing expensive. Yes!, which probably discourages a lot of low cost manufacturers... but if people are not dying and the government doesn't care (unless you a local manufacturer of course!) then where is the incentive to change things.

author: Raj
author_rank: Frequent Contributor
timestamp: September 27, 2018, 04:16:05 am
content: Quote from: labnet on September 26, 2018, 10:58:47 pmPeople are using, phones with aluminium body, more and more, these days. Who knows who'll be the next to get a shock from insulation breakdown?

author: stj
author_rank: Super Contributor
timestamp: September 27, 2018, 08:46:24 am
content: not just phones, 100's of things.including metal-body flashlights.(and wall hooks)

author: madires
author_rank: Super Contributor
timestamp: September 27, 2018, 01:16:50 pm
content: Quote from: labnet on September 26, 2018, 10:58:47 pmmedia coverage != statistics (reported accidents/deaths) != nothing happened, I'm OK, just a tingleQuote from: labnet on September 26, 2018, 10:58:47 pmThat's the reason why countries have standards and enforce them (more or less). And we've designed our systems with several layers of safety. If a single layer fails, such like a poor creepage distance between primary and secondary side, another layer, e.g. the RCD, might save the day.

author: Raj
author_rank: Frequent Contributor
timestamp: September 27, 2018, 04:00:27 pm
content: Quote from: stj on September 27, 2018, 08:46:24 amYes, choose a wrong spot to drill holes for the screws of a wall hook, and Kaboom! electric shock

author: Cyberdragon
author_rank: Super Contributor
timestamp: September 27, 2018, 09:44:51 pm
content: QuoteTechically they should, switching supplies are EMI producers.

author: wraper
author_rank: Unknown
timestamp: September 27, 2018, 09:55:17 pm
content: Quote from: blueskull on September 27, 2018, 03:54:53 pmI don't see any reason why there should be FCC ID. Also, then iphone should be illegal as well, as there in no factory name.

author: wraper
author_rank: Unknown
timestamp: September 27, 2018, 10:06:50 pm
content: Quote from: blueskull on September 27, 2018, 10:01:37 pmWell, there is no address on the iphone or any other device I see around. And you have company name on the power bank.

author: GeoffreyF
author_rank: Regular Contributor
timestamp: October 06, 2018, 01:58:52 am
content: There is a related piece to this discussion and that is the power supplies in LED Incandescent bulb replacements. My guess is that a lot of these products will not last as long as one would expect the LED's to last. The end of life will come sooner than later for the quality of the power supply.Rules are a little different because they don't drive a USB cable to something else and the product isn't intended to be held in the hand as a cell phone is. Longevity is up for discussion and fire hazard as well.

author: wraper
author_rank: Unknown
timestamp: October 06, 2018, 08:47:51 am
content: Quote from: GeoffreyF on October 06, 2018, 01:58:52 amThere are tons of corncob bulbs which can give you electric shock while screwing/plugging them in. Exposed leds are under mains voltage.

author: Raj
author_rank: Frequent Contributor
timestamp: October 06, 2018, 09:31:54 am
content: simple pet plastic cover can solve that

author: wraper
author_rank: Unknown
timestamp: October 06, 2018, 11:48:39 am
content: Quote from: Raj on October 06, 2018, 09:31:54 amThere a lot of bulbs with plastic cover as well. That cover usually is so flimsy that can fall off by barely touching it. Also it worsens cooling. Crap chargers can be made much safer by increasing creepage distance from insane 1mm or sometimes even less, at zero cost. However people producing such crap simply don't bother.

author: madires
author_rank: Super Contributor
timestamp: October 06, 2018, 12:48:18 pm
content: Not at zero cost. A proper creepage distance would increase the PCB by about 2cm², also the enclosure. Just a few cents, but not zero.

author: wraper
author_rank: Unknown
timestamp: October 06, 2018, 01:18:21 pm
content: Quote from: madires on October 06, 2018, 12:48:18 pmNope, usually those PCBs have enough space to increase creepage to somewhat acceptable level just by rearranging component placement.

author: wraper
author_rank: Unknown
timestamp: October 06, 2018, 01:22:27 pm
content: Here is example. Just by rearranging layout a little bit, creepage distance could be increased several times.

author: stj
author_rank: Super Contributor
timestamp: October 06, 2018, 04:26:42 pm
content: that looks like an original i-pad charger!!

author: Gyro
author_rank: Super Contributor
timestamp: October 10, 2018, 09:18:07 am
content: Quote from: wraper on October 06, 2018, 01:22:27 pmThat rectangular through hole pin pattern bottom left looks like the opto isolator. Only an idiot runs tracksinsidethe footprint. I think the one just to the right of it is a Y cap. Likewise!