Poundland's finest solar-powered cable light. This light acts as both a solar garden light in the sense that if I turn the lights off, well, I'll turn it off. right now. it lights up at very low intensity, but then you turn the light back on and watch your eyes.

the light's about to come back. Uh, it can also be used at much brighter intensities. by pulling this cord, it goes from off to low level and then high level and that's not too bad. Now the power source if you take this off here is a 18650 stuffed up the end and what? I've got right now to turn this off so you can actually see what's in there and what I've just done right now because uh, I got a top tip on how to remove this there I Have basically taken the sponge around the outside and look at this solar panel.

That's nice. Why? why is solar diameter 115 millimeters? Very nice solar panel and what we have inside here is Hotmail glued an LED PCB and there is the control PCB and the lithium cell. The control PCB will have probably well, I'd hope the means to regulate the charge from the solar panel, but also it's got just literally glued onto the end with a bit of wire. It's got a little micro switch here that toggles through the intensity settings.

That's quite neat. Okay, well you know what happens now. I'm going to flip the circuit board out and we shall reverse engineer it one moment. please.

Once again, we have a video that is in a slightly different location for the second part because I'm traveling with work and I have to say this is a something that I wish I did of the rest of this light because there's something very odd about the circuitry. I'll let you I'll let you leave your comments down below what you think it is and once I've described the situation whether you think this is a valid functional circuit, but anyway, the back of the circuit board is fairly boring. It's just some tracks and it's got an on off switch which disconnects the battery from the main positive reel. But there one thing it doesn't disconnect is there's a little track here which is part of the charging circuitry and that is a bit of a problem unless this chip is very magical indeed.

On the front, we have the mystery chip and we've got two transistors. One of the transistors is switching the LEDs via these two parallel resistors and the other transistor is controlling the output from the solar panel to the input of the lithium battery the Lithium cell. Um, and this transistor is normally turned on by the solar panels. I'll show you in the circuitry and it gets pulled off by this uh, microcontroller pulling this pin low and uh, that turns it off.

Perhaps peeled off was not the best at word to use there. There's a couple of unpopulated resistor positions. They are our voltage divider across the solar panel that's probably used as a dust dusk sensor for the their chip in here. and there's the pill core toggle switch with just a little micro switch and all its acting is a simple input to the microcontroller.

Okay, let's take a look at the schematic and I'll show you what I have found here, which is a bit odd. I'll Zoom down this right. So here's the sort of panel and it charges the Lithium cell via this transistor. The transistor is normally turned on by that 100 ohm resistor and as I mentioned earlier to, the only way it can really turn that off is for the microcontroller to pull the base.

This transistor law. Now here is the odd bit. The switch between the lithium ion cell and the rest of the circuitry is here, and if you turn that off, it disconnects, it turns this microcontroller off, and and theoretically then there's no way it can sense the battery voltage or actually control the charging. But there is a way it could theoretically do it if I was being inventive and it may well do that.

Who knows if some of these chips are very odd functions, but the LEDs are controlled. Here's the cluster of LEDs. There's two 3.6 ohm resistors giving approximately 1.8 ohms and a transistor, a g3y switching to the zero volt rail. Let's just Mark that zero volt and and it's got one key resistor between it and the microcontroller.

The microcontroller also has that toggle switch, the little pill cord switch, which is just basically it activism traction button, and there's a little decoupling capacitor across the mega controller for stability. Now, the only way I can see that if you get this switch off, that the microcontroller can actually stop this solar panel from charging this Lithium cell up to about 5 volts is if there's some bizarre circuitry in here that uses this connection here. If it made when open circuit, it could detect the open circuit solar voltage. Oh no, that's not going to work either.

This I was trying to invent ways this might work that it could measure what the solar panel was being pulled down to as it because it will be dumping all its current into this Lithium cell. Um, but I I came up with fancible ideas that it's basically a separate section of circuitry that monitors the voltage and then shunts it to the zero volt rail itself. But none of this works. I Think this is a design flaw.

that's why I really want the rest the circuitry. So I can basically hook the solar panel up again and just measure the voltage being sent out to the lithium cell. even maybe put a small lithium cell or a capacitor and output just to actually measure what voltage it charge is up to. But as it stands I don't see any way it can actually stop the charging of that lithium cell, which is strange.

Um, so if you have one of these I would recommend that you leave that little switch turned on all the time. Uh, just in case, especially if you're in very sunny areas, particularly outdoors in a perhaps a greenhouse or something like that where there's a lot of sunshine. because that at least means that, uh, hopefully the discharge at night time of the lithium cell is not. It's going to keep it a sensible level and not let it get overcharged.

I have to get the rest of the circuitry again, But um, I'll let you I like you? yeah? Leave them your own thoughts in the comments below as to how it could be doing this because uh, if it is actually monitoring in any way or if it is actually a design flaw, it's very strange. It would be an easy mistake to make if the people are just putting sort of Lego designs together, but there we have it. It's interesting and strangely exciting. Tour.