Let's take a look at a lurid a USB charger. a little pop-out USB keyring charger which has a terrible secret. A secret that can destroy expensive electronic equipment. So starting off this was supposed to be 1 500 milliamp hour I Really much doubt it because it's it's too late to be that, but we'll measure that capacity later on.

But it's got a pop-out connector and you can choose the one that it comes with I chose USBC but you can also choose Apple compatible connectors. and when I go to I plugged into my USB tester, it's got an input Port here and it didn't light up and I thought all right, that just means it needs to be given a charge and I charged up a bit and plugged it back in again. and uh, nothing else happened. so let me plug this lead it into the output.

You can guess where this is going and get the meter in and we'll put the black connection to Black and The Red Connection to red and the meter says minus 5 volts. So thankfully, the USB tester apparently has polarity protection. It still works. Uh, this thing is putting out the wrong polarity I Think this needs to be explored? How could they do that? That's ridiculous If this is a standard thing.

Has this destroyed Lots of pieces of expensive electronic equipment so it looks as though it's clipped together? Let's prize apart and we'll take a look inside it making sure I don't stab through whatever size of Lithium cell is in here. I should Zoom down on this? So we've actually got fly leads onto that connector that slides in and out. That's interesting. Let me Zoom down and where it goes on to the circuit board.

I wonder if it's the Miss soldered or if the Um wires are just the wrong polarity. Where is that magnifying glass? the red wire is connected to G and the black wires connect to five volts. They've missed one miss soldered the bars on. They've put them in the wrong connections.

Wow, that's a bit of a disaster. now. look at there lithium so see if we can get this apart. The Lithium cell is anonymous I Tell you what.

I'm going to take the circuit board out of this and we'll at least take a look at this circuit board and, uh, analyze it. Now we know kind of what the problem is. One moment, please, reverse engineering is complete. Let's explore and I Have to say I'm feeling quite bad for the manufacturer now that somebody in the factory has sorted these on back to front, because other than that, it's a textbook socket.

It's following the data sheet of this chip, the power bank chip, to the letter, and it's also got our dedicated little Lithium cell protection circuit on it. So let's take a look at what's on here. Other things worth of note here here is the USBC charging port and it has the two 5.1 K resistors connected to CC1 and Cc2 the signal to whatever device you're going to plugged into that it's looking for current. That's really good.

A lot of stuff just misses those off and that results in things like rechargeable head torches and things like that that just don't work if they're plugged into some power banks. In the case of this one, it does send the correct signal back. It has the T Power Tp4333 Power Bank chip that's a generic power bank chip. It's got a couple of LEDs pins to indicate uh, the charging and the load status.

It uses the inductor of capacitors um to actually provide the five volt Supply and it also has unused in this case, the switch and the LED arrangement for those power banks with the clicky button and the LED comes on. On the other side of the circuit board are the two LEDs associated with that um and the Lithium Cell Protection chip 3160. not sure that is and it's the Tool Uh filter Network Everything is textbook. All the correct capacitors are here.

the little snubber Network here in the input. let's take a look at the data sheet which I've just basically augmented. I'm going to turn this down just a little Tad There we go. So the incoming Supply comes in here the USB charge connector and it has those two resistors going to the zero volt Rail and it's also got that number Network that they seemed to use.

1.5 Ohm and 2.2 microfired as a filter presumably divides provide stability on the input and uh, that then goes to charge the Lithium cell here which has its little protection chip and its little Network Now, the resistors are tiny, but I Can guess that's 100 Ohm and that's 100 nanofarad. That's what they usually have. Uh, there's the two LEDs Uh, the bit of secretary that's not used the button with the resistor in the series for uh, signaling that it wants to turn the LED under off. It's a sort of double click thing usually.

Um, there's the inductor at the battery connection that's capacitor for stability and the output of 5 volts. So that's capacitor probability that someone just connected onto back to front. That is it. It's actually quite a nice circuit.

It's a nice layout in the circuit board. It's all fairly textbook. Um, what a shame that it's just lack of quality control that someone just sorted those connections on back to front, But that is it. It makes me wonder how many are similar.

One of the advantages of having the connector just fixed and actually mounted in the circuit board is that Well, you can't really make mistakes like that. It gets sorted onto these standard pads and you can't mix them up in this case because they've got the red and the black wire coming out. It means that a tired factory worker or one who's just not been shown how to do things correctly. Uh, can just tack these on back to front and they're and mess that up And that's what's happened here.

Such a shame. Nice little power bank. Now the Lithium cell that was in it is not huge capacity. It's current under test once.

I've got the result of that. You'll find it in the description down below, but I can tell you it's not 1 500 milliamp hour as stated in the eBay listing because eBay listings lie. But other than that, you know for a small power bank, it's actually quite neat.