As HKJ has noted there needs to be good isolation or insulation between the parts of the circuit working at mains voltage and the rest. Any wall-outlet-powered spark can jump a good distance And if things are really close together, that arc can melt stuff and create a continuous current path
In my business of repairing rental homes I come across many wall-warts that get left behind. The ones I prefer to use are those from brand-name phones as those will have good QC in manufacturing and a good, safe design. The others I use for repairs. I can’t remember when I bought a wall-wart last; it’s been at least 20 years ago or more
I have no idea what I am looking at for the most part as far as if it is any good or a death trap. The first picture is actual size… the rest are zoomed in.
Check out those pink wires though………. … :+1:
If anyone can tell anything about this thing from the pictures, please feel free to share with the rest of us. :+1:
These only cost $1.45, so I don’t expect a whole lot……. :person_facepalming: …
These look like the same i got from FT - at least the markings and model number S-100D (which differ from the picts on FT). I have yet to pry one open (how did you do?).
As i said, i’m suspicious about those. Since then i bought a usb tester which reports 5.2V and 0.3A at best while charging my phone with very unstable numbers…
They sure do look the exact same (except for the plug of course). Just insert a small flat head screwdriver in the gap where the white meets the black & pry. The white part with the plugs snaps into the black housing & should pop right out.
I have misplaced my USB at the moment :person_facepalming: , but when I find it I’ll report back what I find when testing mine.
The primary-secondary separation on this one is marginal at best. It might pass a megger test, but I would not use it. The other typical weak link in the chain would be the transformer itself, but this is difficult to judge without a megger test or disassembly.
At first i though it was exactly the same as yours but when i looked at your pictures i realized there was some notable differences in the layout. It seems they are two different versions of the same design. The components are the same i think, but they are organized slightly differently on the board… I’ll try to post some picts later.
The primary/secondary separation is 1.5mm on mine - unsafe if i understand well… but i’m not sure what i’m talking about.
Thank you ’DEL’!! :+1:
I won’t pretend to understand all you said, but I’ll take your word for it.
But, can I assume the yellow line shows the “primary-secondary separation” you mentioned? With the ‘secondary’ on top & the ‘primary’ on the bottom?
Also, is a “megger test” where the adapter is introduced to excessive voltage to see how it holds up?
I think, (if I am understanding correctly) this is where ‘HKJ’ uses 2500V & 5000V??? (referenced below) Is this a “megger test”???
High voltage test
For this test I connect the two mains wires together and all the usb output wires together, then measure the resistance between mains and usb.
This resistance will be very high, but on some equipment the insulation will break down due to the voltage, this must not happen! Mains equipment without any earth connection must be able to handle 5000 volt DC (Safety standard says 3000 V AC or 4243 V DC for 230VAC supply), between mains and low volt side.
With this test it is very important to keep away from the wires when the test voltage is on!
Good! Yeah it just ‘pops’ right open, :+1:
Can you post a picture of both sides of your board as well as the plug end where the model number & specs are?
I’d love to see the difference.
Thank you ’patmurris’!
I am gonna study that and see what seems different. Like you said, they both are exactly the same on the outside except for the plugs. Model # & specs the same. I did not show it in my pics, but even the clear plastic wrapped around it is the same.
The inside is definitely not the same though. :question:
However, yours is obviously inferior since it does not have pink wires………… . …
… well, the inside is organized differently but the components look the same. Overall it’s the same charger, just another version or something. What i mean is there is not a huge difference as there would be against a genuine Apple charger for instance.
Now trying to source some pink wires to upgrade mine… :person_facepalming:
PS: this whole “cheap but safe charger” thread is turning into a “USB AC adapter tear down contest” kind of thing.
The bottom line is i will not include any such unknown device in my gift set - everybody has a couple ones already not mentioning usb ports everywhere. I’m still curious to hear about a fair deal on these adapters for 220V. I think the Apple 12W adapter is sold around 25 euros. The Opus BT C-3100 was not much more expensive these days on GB!
“Organized differently”, I completely agree. That is what I meant, but you said it much better than I did. :+1: And yep, I bet there is a huge difference between ours and a real genuine Apple one.
I have been able to “match up” all the ‘parts’ they share in common that look the same. There are only 3 or 4 I am not able to match. Of course they may be the same thing and just look different…. I would not know.
Yeah I don’t blame you for not gifting them, that is what I had in mind too…. but not now. I am going to quit using the ones I have been using with a couple of Lii 100’s also…. better safe than sorry now that I know.
Megger is a popular brand name for, and it became synonymous with, portable insulation testers. It is the ‘Fluke’ of insulation testers. (It also somehow became a verb in the electrical trade.)
Insulation level is measured in mega-ohms and is evaluated at high voltage, typically 250, 500, 1000, 2500 or 5000 V, depending on the application. A regular multi-meter, in contrast, measures resistance by applying only a couple of volts over the device measured.
These chargers are supposed to be double-insulated. As far as I know that requires a ‘creepage’ clearance of >6.4 mm between bare conductors for <300 V devices. But there are several regulating agencies and several nuances depending on the application. This is also a safety requirement, not a functional requirement, and the device may work fine under normal circumstances. I am not plugging my phone into it though
The Blitzwolf chargers are cheap enough and well built, if you are OK with shopping at Banggood. See HKJ’s reviews.
And if things are really close together, that arc can melt stuff and create a continuous current path 
…