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This is a useful 12V light in a very common form factor that seems to have become a standard. The bizarre name "purification light" actually makes it easier to find these online. The same style of light is referred to as a grill fitting by CPC (A prominent UK supplier).
The light comes with a double sided foam adhesive strip and also the more traditional concealed metal clips for attachment to a surface. The foam strip may be useful for vehicle use, but the clips would be preferable for wall or ceiling mounting indoors.
The circuitry is refreshingly simple - just LEDs and resistors, but it should be noted that running this directly from a fully charged SLA/Lead-acid battery will cause much higher LED current than normal. I tested it at various voltages and got the following results:-
8V - 32mA - 0.26W
9V - 195mA - 1.75W
10V - 378mA - 3.78W
11V - 595mA - 6.55W
12V - 804mA - 9.65W
13V - 1012mA - 13.16W
14V - 1237mA - 17.32W
If using for long periods of time on a lead-acid battery supply that may float to 14V during charge, I'd recommend at least two diodes in series to drop the voltage slightly. Like 1N4001 series diodes.
This light came from an Aliexpress seller. Note that many of their other items at unusually low prices are salvaged or factory rejects. This item was ordered along with several packs of LED filaments that came pre-broken, and also some small motor assemblies that had clearly been removed from equipment, and of which about half were faulty - including really obvious things like missing shafts.
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An led baton, light bought from aliexpress for about three pounds: 15 inclusive. I got this to take apart, see what it's like inside. So it says, led purification fixture, not sure where the translation went wrong there, but what you get inside here is a classic little baton. Light and sometimes they call them grill lights for some reason, but it's got the usual little metal clips that can go in to actually attach it to a surface, but in this instance it's also got double-sided tape.

Unfortunately, it's got double-sided tape on the back of where the uh, the heat dissipation surfaces for the leds, let's get the two leads and a little click on click off button. Let me apply 12 volts to this right now. I have tested this at various voltages. It's important to note that it is optimally designed for 12 volts because, when put on at 12 volts it dissipates about 10 watts.

It draws just under an amp and if you were to use this on a solar panel and sealed lead acid battery system, where the battery got charged about 13.8 volts. The current at 14 volts is 1.237 amps, and that equates to about 17 over 17 watts, which would actually potentially overheat this. So it's one of these things that, if you're going to use it in a system like that i'd, probably recommend a couple of diodes in series just to drop the voltage a little bit. Let's open this up, i should mention that it does start lighting up at 7.4 volts that does suggest it's got the series clusters of three leds.

Now i don't see any screws in the back here. I don't know if this is glued together, it's uh clipped together, apparently, okay and it's got the usual arrangement. This slides out. This also looks strangely sort of filming this.

I think, there's a protective film this. Let me just uh, i'm not sure i thought initially. This may actually come out, but it's all molded in together, like these lights, tend to have. Does the other end come off not easily? Okay.

This is the end we want off. So what i'm seeing here is multiples of nine leds with a resistor per three leds. That's good, i thought it might be going to be using one resistor for the whole lot, as sometimes happens, but it has divided it down um and there's a little switch in the end uh. I wonder how, technically speaking, based on how sensitive this is, you could also use it as a night light if you stuck i'm gon na, try that i'm gon na put a resistor across this one moment.

Please continue the experiment, so at 12 volts, if you put a resistor across that switch even at a level of something like 3.3 000 ohms. The current draw is about one milliamp and it's actually still quite bright as a night light. In fact, it's really surprisingly bright. I'm going to keep going i'm going to keep going higher, so this is actually 33k now in sears and it's still visibly lit.

Let's bring the leds out, i'm just playing about here - i'm just messing about here. Let's see how far i can go with this before they're, this is the highest. It goes to it's one, mega, ohm and they're actually still visibly lit. That is ridiculous, uh.

So that's an interesting option that if you wanted light now watch your eyes, i'm going to bring the light back. So this does kind of introduce the possibility that if you had one of these running a 12 volt supply, you could have the switch to turn it on and off. But if you put a resistor across that it could run at just a really low current. Like one milliamp and it could provide low level ambient lighting as well, just as a 24, 7 security or or just comfort light, i have tested this.

There is a film across it to protect the uh to protect the front. Oh, it feels sticky. Now it's the usual construction, nothing really radical to say about it! It's nice that they're driving the leds properly uh! I haven't worked out how much power that is, though i write too well. I'm gon na have to work out the power now one moment please, the computations have been done.

The current through each led is roughly 38 milliamps. That gives a typical power dissipation per led of 0.038 38 milliamps times round about 3 volts voltage drop across the led about 0.114 watts between across the led each led. It has potential. Adding those diodes in series will reduce the dissipation.

That depends for application. Maybe you want the fuel intensity, but if certainly if you're running off the rechargeable lead acid battery, i would recommend adding those because it is going to push these leds a lot harder and it is relying as these things do, on the heat dissipation of this plastic Plate just loosely slid into this channel here, so the thing is going to last a lot longer. If you under run it um and i like that's a nightlight idea, is there anything else to say about this? Not really it's useful, where i could see in the future. If there were power, outages then having a 12 volt system, it would be quite useful to have something like this uh, but certainly if you live in a camper, a trailer or if you want extra lights in the back of your vehicle, this looks as though it Would certainly fit the bill, but i would say just add those extra series diodes and just to nudge, the voltage down from that sort of peak charging voltage and to actually make it make the leds last a lot longer.

And they should give a decent length of life, but it's very neat: it's typical construction, it's what you'd expect so that is it! It's uh. The strangely named led purification fixture strange that i don't know why they call it that, but that's it a very simple arrangement. Uh multiples of three leds with a resistor for led just like the led tape and just a little switch the end and everything just on this little aluminium panel. That then goes into that.

Uh that strip light fairly standard and absolutely fine.

18 thoughts on “Inside a cheap aliexpress 12v led light”
  1. Avataaar/Circle Created with python_avatars Steve D says:

    The funny thing is that I have been 'upscaling' some of these cheaper, but better made units- fix the 'factory faults' then onselling to the camping/offgrid community…
    Yeah I add a little to the price, but they are also much more reliable longterm… good for us 'semiretired' folk fix their elcheapo screwups and make a few quid on the side lol
    Hardest part is finding the 'cheap but still OKish quality units to use as the basis…

  2. Avataaar/Circle Created with python_avatars John Nodge says:

    Thanks for the Video Clive.
    I've just ordered 4 for my various solar powered lighting solutions around the workshop and garden sheds. For under £2 ea + shipping is very reasonably priced, and perfect for my usage.

  3. Avataaar/Circle Created with python_avatars agvulpine says:

    You should give us plebs a boost of confidence by telling us more about these diodes you speak of and what ratings to look for when shopping for them, or what devices to harvest them from.

  4. Avataaar/Circle Created with python_avatars Dyrck says:

    I have two mains powered versions of this, from CPC, in my shed, they give a really good bright white light. Unfortunately one of them has a quite loud 50Hz hum!

  5. Avataaar/Circle Created with python_avatars WECB640 says:

    This would make a cheap "on air" light for a HAM shack. Just make a transparent overlay in your laser printer and paste it over or inside the housing.
    Simple 12 volt, easy to switch with a relay and safe to wire. NICE! Put a CDS cell in series and it will adjust to the light in the room so it doesn't burn your eyes out as you warm your feet with the amplifier in a dark room. LOL

  6. Avataaar/Circle Created with python_avatars shamelessFNGRL says:

    Hey Clive, recently they found out that a lot of Shein/Ali products (for some reason especially children's clothing) contain insane amount of lead! 5 to 20 times 'safe limits'. Please be careful, and if you could, would you mind doing some lead detection tests on any of the items you got from Ali? On one hand I'm asking for shits and giggles, on the other hand because I can't do it myself… It's really hard lately for me to find Pb indicator. Thank you in advance~~

  7. Avataaar/Circle Created with python_avatars D W says:

    The things I love about this channel:

    1) The random impulse buys just to take apart and see what's inside.
    2) The random thoughts you let us in on and then experiment based on those thoughts.
    3) The educational aspect of the channel.
    BONUS 1: Retinal fusion shock pink calculators!

  8. Avataaar/Circle Created with python_avatars pyromaniac303 says:

    Did you know that you can run LEDs too low and damage them? I was working on the analysis of returned automotive products at a well known German manufacturer and the symbol illumination on the window switches kept failing or becoming discoloured after about a year or so use. It turns out we had used super efficient white LEDs and they were running at less than 100uA! Under the microscope only part of the die was lighting up which was causing the phosphor to age rapidly. Solution was to swap to less efficient LEDs! This was in ~2008 though so not sure if it's still the case and I'm yet to this day find a datasheet with a minimum current spec. I treat them like switches now as if they have a 'wetting current' of about half a mA and never had a problem since.

  9. Avataaar/Circle Created with python_avatars Joe Brown says:

    Nighttime illumination using broad spectrum lights is responsible for a sharp decline in moth populations and consequently bats and other wildlife too. Moths are attracted to bright lights. So I hope people do adapt these to be much less bright if using them for outdoor security lighting.

  10. Avataaar/Circle Created with python_avatars girlsdrinkfeck says:

    my workplace ( morrisons supermarket ) just had all new LED fitting installed ,using phillips titanium drivers , looks very expensive ,i bet it cost lrast half a million to do every light in the building ,they include IR sensors /and theyre all off or dim and first and turn on or brighten up to full intensity when it detects motion, its very jarring ! PS i looked at one of the boxes ,i think each strip 0.5 metres ,is 150 watts !!!!!!!!!!! thats a lot for a LED ,then again its better than the 500 watt FL tube lights they had ?

  11. Avataaar/Circle Created with python_avatars Andrew Edis says:

    Clive have you considered looking at LED grow lights for "Tomatoes"? I still use HPS lights with a ballast and ive always assumed that an LED system might be cheaper on my electric bill but I honestly don't know.

  12. Avataaar/Circle Created with python_avatars Seth Murphy says:

    Alternatively, you could just take that el cheapo Chinesium switch off and replace it with one of those click on pots (kinda like a volume switch), then you could set the intensity as you please at any given time. A 22k pot would probably work best. That would run the whole 0.5mA and dissipate approx 6W which is nothing at 12V.

  13. Avataaar/Circle Created with python_avatars Niall Tracey says:

    The one question I always have on cheap LEDs is whether they’re “video safe” or not. I didn’t notice any strobing in your video so I assume they are constantly on, and the summing you achieve with the resistors isn’t something coming from a controller board disabling the LEDs momentarily…?

  14. Avataaar/Circle Created with python_avatars Tiny Tony Maloney says:

    I got 3 of these, very similar, may even be the same, to run off a solar panel/ 12v wind turbine for our stables. Not actually installed it yet but I like the idea of the resistor across the switch, good modification that. 👍👍👍

  15. Avataaar/Circle Created with python_avatars twocvbloke says:

    Even just a couple 20w paralleled solar panels in my window hooked up to a (now dying!!) roadside-salvaged car battery works nicely for 12v lighting, though I found that lights that are unregulated like this tend to be noticably dimming when they start to pull the batteries down, versus the 4W bulbs I got (similar style as a pygmy-type one you got some time ago with the ceramic LED filaments that turned into a bit of a disaster vid) which have a regulated buck-boost supply in them, only downside to those is they work great well below the battery's officially discharged voltage, which isn't healthy for an already tired lead-acid battery!!! :S

  16. Avataaar/Circle Created with python_avatars Ben Snow says:

    Resistors? No, thank you sir, we only use diodes in series here.

    That said, if they have a current-independent voltage drop, that does sound profoundly useful. Wonder why don't they just make them in arbitrary voltages, could be great when for example you have a 9V circuit and you'd like to drive it with a 5V microcontroller, just put a 4V diode on the power rail and any inputs and you're done. Or you would be, if the component was available, right now you either have to use like seven diodes, or just build a proper step-down converter, but that's boring.

    Would there be any drawbacks to this strategy?

  17. Avataaar/Circle Created with python_avatars Kim Christensen says:

    You could mod it and put a 800ma constant current source in series with the supply lines. Then it's brightness would stay the same from 12-14Vdc. I bought some LED replacement bulbs for my RV (caravan) which use this technique so that the current and brightness stays constant over a 11-15V range.
    Or just feed it through a 12V LDO regulator instead.

  18. Avataaar/Circle Created with python_avatars .x. says:

    It doesn’t get simpler than that big Clive.
    Well I think I’ve been watching you for seven years since anni exploded at least
    And I sure know A heckuva lot more about how to use resistors diode‘s capacitors and light emitting diode than I did when I started watching so thanks for bringing me this far and don’t ever quit. Xoxo.x.

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