Yet another eBay special. A cheap USB powered charger for nickel metal hydrate or nickel cadmium cells. and I've done a little bit of premature exploration in this and it's got its quirks. However, let's plug it in and see what results we get.

This one was fairly cheap. They've kind of got rid of the cable and it's got the connector straight on it. I Guess that if you've got a suitable power supply, you could just plug this straight into it and dangle it from the wall I'm not sure how strong that would be if it might just dangle and drop out, particularly with the weight of all the cells in it. However, if I plug it in, two things happened: A little red LED glows in here and it passes 240 milliamp milliamps into the cells.

However, if you remove a cell, the car goes down a little bit. remove another one, no changing current, remove another one. So if I can remove another, one goes down a tiny bit. and in reality at all the sound positions are just connected and parallel in here, so it's just basically providing well, presumably one resistor for the whole lot.

It is limiting the current though. this is good, it's not doing anything too weird. Let's open it up and explore the insides. I See some clips here I'll get a screwdriver and undo the clips.

It looks really undo like this. They do undo like that. What else is holding this shot? Is it being held shut by pins? Maybe Oh yes, there are pins in there. Let's uh, pop those pins out.

Oh in this area, kind of clamping all the other more pins in the connect. USB connector. Is it glued or something? Oh no. that plastic's going through the connector.

The actual connector is part of the circuitry. Really? Oh okay, is this going to come off at all? Am I supposed to pull this shell off I don't think it is I think I may have to use unreasonable Force I Just have used on reasonable Force to kind of snap that off the look of it. Oh, that's not great. That is very minimalist design, right? Tell you what? I'm gonna have to cut a wire here and then hinge it up like this to reveal the circuit board.

There's a diode. Yeah, that's uh. that metal shell has literally been slipped. Hold on.

let's get the flowers and see if we can rip it off. Rip it off. There we go. Oh, the circuit board itself is part of the connector.

How Low Can You Go I Mean, it's good, but it's bad. Let's take a closer look at this one moment, please. Well, that didn't take long to reverse engineer. it has been reverse engineered.

Let's resume. I'll ignore it. It says in the back of the case here it says at 100 to 240 volts, 50 60 Hertz No, it's just 5 volts and it says 120 milliamps. I'm guessing this is just a case that has been copied for or repurpose from another product.

So the circuitry is very simple. Let me Zoom down, Not. There's much to see. Here is the bear end of the circuit board that goes into USB connector.

The positive goes to an LED and also to this diode and then out to the positive to the cells. The negative goes via this resistor to the LED and then via this 12 Ohm resistor. That's one two, zero, one two, and zero as the decimal multiplier. So it's just 12.

Uh, and that goes out to the batteries. Oh, one oh, two, one zero, and two zeros. 1000 Ohms. Let's bring in the schematic, not that it's really needed.

Is it anything else worth mentioned about this? The data connections are not connected. This is good because that means that there's no way it can negotiate a higher voltage, which would be just as well. Really, this is it. The USB Supply Community the LED across that Supply with its resistor, the diode which is standard one amp diode going out to the positives of the cells and the 12 Ohm resistor going out to the negatives.

The resistor could theoretical anywhere in the circuit. Just to basically you could put it up. here it's in a series circuit, but the downside to this is that if you were to put in one cell that was fully charged right up to the hill, maybe it had been charging for a while and then you just thought I'll pop another cell in, that's pretty flat and you're stuck it in another position. You'd Bridge them together and you could get quite a high current flow.

But having said that, one of the joys of nickel metal hydride cells is they spend most of their life at roughly 1.2 volts, so there's not going to be a massive current flow. The connections: You've just got the spring plate for the negative and the indented plate for the positive that is. It could be useful for the contacts for the case or as a battery charger. It's not going to be a disaster.

Also, interestingly because the open circuit voltage will be about oh, just over four volts technically speaking, although it's really not recommended, you could put a protected double a lithium cell and as long as a protected one and it will charge it up to the point it cut off on its over voltage protection. not the correct way to charge these. particularly given that some of these lithium cells with a little gold protection piece to be an end. Sometimes the PCB is blank and it is a fake protection circuit, but that is it that is the super duper cheap.

Uh USB Charger: A Quite neat construction I Have to say, even for its for its penny pinching. Um, quite unusual that the circuit board just lays in like that and then gets clamped down by the case and then the metal housing just slipped on over that. Oh, I've broken a bit of metal housing off I Think that's the bit that may have been in between this plastic here, But quite a minimalist construction. Very easy for them to make, very cheap for them to make, and I guess that's what it's all about.

It is a very cheap, simple charger just designed to do the job and be manufactured as cheaply as possible. And for that you know it's impressive. but not really. 100 recommended.

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