You are in Europe, i.e. 230VAC country, that means you need at least 4 mm in safety distance.
It looks like you have 2mm and if the letters are in copper, you have even less.
The circuit does not use any IC's, but has optical feedback.
Wow, amazing how many bad USB PSU’s there are out there!
I would be very curious to see testing from more major brands like HTC, LG, Samsung OEM power supplies. I would hope and assume that they are quality products. In the past I’ve bought samsung and LG USB power supplies for as little as $3-4 shipped on eBay from US sellers.
Also forgive me if I missed this, but how are you loading them? Programmable DC load? The same one you use for batteries?
Usual a electronic load, but for noise I am using resistors.
I have made this resistor box:
Then you very likely bought fakes, at least the Samsung ones.
The original Samsung and LG chargers are quite good, the fakes not so much.
Well the Samsung one I bought looks and performs the same as the one that came with my samsung phone… So if it is a fake, its a damn good one.
Of course it looks the same, that’s why it’s a clone… How do you know it performs the same? Did you test it with a multimeter and an oscilloscope?
Here is a test of a fake Samsung charger: A quick test of a counterfeit Samsung 2A charger and another junky charger
Does anybody know if on the multiple USB port chargers, the USB ports are isolated from each other? That is, they do not share a common ground? I would like to be able to charge 2 cells wired in series, in place with 2 of the little mini USB circuits as found on eBay. Everything would be wired in place and I am assuming that 2 separate wall warts would work. My question is whether 1 multi USB wall wart could be used instead, using 2 USB cables, 1 to each of the 2 mini USB charging circuits.
No, they are in parallel.
Thanks, HKJ, looks like its a garbage, wont use it!
Yes, datalogging multimeter for testing USB chargers. However I will admit it was at 500mA, not 1A, but also the open circuit non loaded voltage was the same on the ebay one as the one I got with my phone. 5.2v IIRC.
Not everything that is cheap and OEM out of China is fake. Sometimes suppliers sell “under the table” and step around samsung / lg and ebayers get ahold of them.
Everyone thinks their counterfeit product is from the urban legend of “the night shiift”, but in reality there is rarely any night shift. At least 99.99% of “Samsung” chargers out of HK / SZ are fake. You may be OK with LG as that is an unknown mobile phone brand in China and I don’t think anyone is bothering making clones.
If you bought in USA you may have been lucky, but on ebay for $3 including shipping from China: forget it. In Europe I see lots of online sellers selling the same fake Chinese “Samsung” chargers.
What about buying Samsung charger from an actual store? Are they guaranteed not to be fake? Even Amazon can’t be trusted for some electronic products with so many sellers exporting fakes.
Oh, about the Samsung version of the Pisen dual charger, I could only find Apple version on Ebay and AliExpress. I put in a product request for it at FastTech.
Ideal travel USB charger would have switching for both types and able to deliver 3-4A in small form factor. I am guessing they’re ultrasonically welded so no way to mod them nicely.
Maybe some smaller stores sell fakes but the bigger ones should be OK. Brick and mortar stores that is. Lots and lots of people have received fake Samsung chargers from Amazon. I know my chargers are genuine because they all came with mobile phones, cameras or tablets.
I have dozens of small quality(=original) 1A chargers so I have no use for a big bulky two-port charger that only outputs 2A. I’m not 100% happy with my original Samsung 2A charger (the voltage is a bit too high) so a small good 3A charger would be nice (the best higher output chargers I have are a Sony 1.5A charger and ASUS 2A and 1.35A chargers).
The Pisen charger is only available with Chinese plug, but it would still be interesting to test it.
I might at some time test a couple of these again. For people that would like to get a specific charger tested, please post a link where I can get it.
This one is a little interesting: Page Not Found - Aliexpress.com
2A version of the Pisen “Samsung” charger: Page Not Found - Aliexpress.com
HKJ mentioned the creepage distance as being completely inadequate. Also, no Y capacitor across the line. Zero filtering logic. Cheap resistors. Unwrap that little transformer and find out how safe it is (you might be surprised). Looks like they are using a standard resistor as a fuse (it should be flame proof), it even looks like they tried to make a fuse in the trace on the back of the PCB, (variability is enormous with this technique and is just plain bad).
Test it.
Oh… and when your done, don’t put it back together, chuck it in the bin.
I found this one on DX that can supply 3A (across 5 ports):
http://dx.com/p/5-port-usb-eu-plug-power-charger-adapter-for-iphone-5-ipad-mini-more-white-223006
DX also have the “thunder charge” mfm posted above:
http://dx.com/p/dt-adapter-2usb-15w-dual-usb-power-adapter-wall-charger-white-215042
The “thunder charger” seem very Apple-centric and the first one is the same as one on FastTech I think?
Anyway, today this 2A charger was banned from sale in Sweden: http://unplug.com.hk/tc2000.html because bad internal isolation in the transformer (and lack of proper CE declaration of conformity):
Maybe “hobby testers” also need to check the transformers (or would the 5 kV test detect it?).
[quote=mfm]
This is exactly the reason I uses the 5 kV test, it will reveal the worst problems with short distances and bad isolation.
But there is a considerable gab from passing a 5 kV test to passing a CE test.
A picture of what 5 kV can do:
