In a recent video, i took a look at a safety vest that was basically a hi-vis vest that had strips of leds in it to make it even more high-vis and inside was this quite nice, uh 3-cell lithium battery pack and it came with the option of Chargers that came with a mains voltage charger and it came with the vehicle chargers and these all say, input 12 to 24 volts output, 12.6 volt, 1, 000 milliamp. This is a universal 100 to 240 volt and but the same 12.6 volt, 1, 000 milliamp output and in the circuitry, when you plug it into the jack on the device. I've got one of the little jacks here and it's still in its sleeve. It basically puts the power straight out to the battery, so this is basically connecting straight to the battery to charge it, and i wonder why they were selling them off, because they were selling them off very cheaply uh.

We were just into it to get the battery packs out these because they're quite useful and the chargers, but then i discovered that the low voltage chargers aren't what they seem and although they may look identical it makes me wonder, has this what's actually resulted in these? All being sold off because there's a lot of work in the vests, but if you look at these they've got roughly the same such shape, but they've got the different ends and they have the same labeling, the uh, 12 24 volt. This one does have a model number, but this one is a sort of like the sort of pits in it but range of like a pool table, the sort of like all the balls lined up and this one's got the deeper pits. So it's three different chargers: let's explore inside them because one of them is not at least one of them is not ideal. So this one has a little red led in it and that's a clue.

This one is a clear led, and this one has a diffused led so to open these. You unscrew this bit at the end fuse pops out. You may need to change the fuse if you use it 24 volt. Well, you may need to change your pants and you may need to change the cab of your vehicle if the batteries burst into flames.

That's just pinged right across there, because this charger, despite saying for 12 or 24 volts, i thought. Oh this reason. Let's get resistors for just 12 volt use except the resistors are not in circuit. Let me zoom down in this actual draw the circuit diagram.

If this is oh, it's not going to take long. It's not a good thing uh, but there are four resistors all with identical value. I think they're for theater red black red. That's 2k i'll! Tell you what one moment i'll draw this schematic the schematic.

So here is the car end of things. There's the positive there's! The negative out this, the plug, it goes through a two amp fuse, and then it goes up to power, the led with the 2k resistor and then there's a row of 2k resistors. I think they just put the same value in them all, just basically, because that's what they had. It looks as though it may have had been designed to have some sort of resistor to each output, but in reality the output to the lithium cell is just right across there and it's got the protection circuit built on.

But the protection circuit is not there's. No current limiting here and if the lithium cells were low, they'd be around about 9, volts or less or if they were fully discharged, but about 7.5 volts, and that's a cut-off point. So then, if you plugged it in, it would just smash current into that um and if you plugged into 24 volts it would be extremely bad news. I hope i'm not sure the protection structure do think it would kick in when it saw a serious overcurrent situation that fuse would probably blow so that is an abomination.

Now there's this thing that uh manufacturers who get products made in china. This is a dutch product. It's a designed, uh and manufactured by a company in the netherlands and oh there's, a there's, a wire sorted across the outside of this. Oh, oh, maybe the fuse did keep blowing oh, oh, i swore hey hold on i have to.

I have to make notes of this. I have to make notes of when i swear, i swore just to remind me to tell uh i do it quite a lot, but i'm supposed to actually mark my videos when i say things like that, i wasn't really expecting to see it with these. What's this going to be, it is oh they've saved money, it's got a smash circuit board, oh and there's one resistor, really 1.5 k, brown, green, red and sears the led, and it's just going straight out again wow. I was saying there there's this horrible thing that when people get stuff manufactured in china, they, the big companies, have to send somebody across to supervise that and check all this stuff that they deliver, because you just never know what you're getting here is a big fuse.

This is feeling a lot better already. This might be a real one. In fact, is there going to be a little screw under here? Maybe nope? Let's have it open here we go. This is the proper thing.

With the look of it, we have a regulator. Chip um, we have a transistor here, boosting it up, so this might be actually for a fairly decent current, because that does seem to be coupled to that and we've got a little transistor connected to possibly the leds. Yes, it is which will be the end of charge. It will just be a basically a simple voltage reference just to say when the current stops, probably it'll just be measuring current across this resistor i'd guess, and this resistor and output may actually be uh to limit the current.

I'm not really sure if it's going to be used for that. Oh this resistor here could be a factor in that uh or that's the sense resistor for the actual switching device. So maybe this is regulating the current as well. But this is the real thing, but but what happens? Is the factory manufacturers a product and they get it made in china? There's no saying what you're actually going to get back um they may skimp, they may change a component, they may improvise.

They may do what this has happened here. They may substitute that something that looks identical, but save them a lot of money when they send it out, but in reality, they've taken all the safety out of the product and now that's why there's a local company here in the iron man called strix and they Make kettle switch mechanisms and the reason they can still manufacture stuff like that on the isle of man, is because the manufacturer for that safety, critical component. That is going to turn that kettle off and not burn people's houses down. They want to be manufactured by a company that operates proper standards, the correct materials tests, everything and is a bit efficient with the paperwork, but uh gets the result.

So the moral of the story is here: if you ever go into manufacturing, never fully trust um overseas manufacturers to supply what you were expecting uh, that is quite dire, particularly the wire soldered across the fuse, because the previous one well, the actually previous wire, is still In there they've just beefed up a bit: that's horrific er, but there we go. That's that's an education. You don't really want to basically stick a lithium battery pack directly across 24 volts with no current limiting that's just plain freaky.