Yeah another dooby-lamp video. But it's the trashiest lamp I could find this time.
Another look at a mass produced generic LED lamp designed to burn bright(ish) and fail fast. Because it only costs a dollar/pound nobody is going to bring it back for a refund.
The most intriguing thing about this one is that it seems to be from a mass producer of these lamps for many brands, but this one has been optimised for being extra cheap and nasty.
After hacking the 5-LED one I measured the voltage over the LEDs at 250V. That's 50V per LED suggesting around 18 LED chips in each LED package!
Even with the dooby hack it's still dissipating just under half a watt per LED. But it's still going to last a LOT longer than in its original form.
Here's a link to the video with the crystal 3D files in its description:-
https://www.youtube.com/watch?v=HZKu9QMN5xw
Adrians teardown of a Dollar Tree lamp similar to this one:-
https://www.youtube.com/watch?v=NbFmecSdycw
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
Another look at a mass produced generic LED lamp designed to burn bright(ish) and fail fast. Because it only costs a dollar/pound nobody is going to bring it back for a refund.
The most intriguing thing about this one is that it seems to be from a mass producer of these lamps for many brands, but this one has been optimised for being extra cheap and nasty.
After hacking the 5-LED one I measured the voltage over the LEDs at 250V. That's 50V per LED suggesting around 18 LED chips in each LED package!
Even with the dooby hack it's still dissipating just under half a watt per LED. But it's still going to last a LOT longer than in its original form.
Here's a link to the video with the crystal 3D files in its description:-
https://www.youtube.com/watch?v=HZKu9QMN5xw
Adrians teardown of a Dollar Tree lamp similar to this one:-
https://www.youtube.com/watch?v=NbFmecSdycw
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
Thanks…Great videos! Then why do some led light bulbs have a driver board…lets say a tube light with 178 leds, looks like a two color alternating set up, seperated into three groups of 58…each group with their own resistor…this is a 120 volt mains unit?
Clive…are you saying that there is nothing below the led boards but the mains wiring??? So if you were to expose that area you would have just two wires to the back of the led board???
Aldi in Germany recently sold lamps rated as 2.2W/250 lumen and on the inside they look basically identical to this cheap poundland lamp with its 5 LEDs. They don't get very warm when in use…
There is extra components to ones in america, do you want some? Ive been trying to revive some but they do so much foolishness since im not trained it hasnt went to well. Idk when i would have to money to do so. But I kind of wanna figure out how to fix these things. They had contacts & resistors & everything in them. Normally they were like LG 8$ USD but i got them on sale a couple years ago at a clearance for 1$ so i bought a bunch. The circuitry seems pretty advanced but has the same type setup of those.
Could you look at the power factor of the different leds. I imported some no name leds from China years ago and whilst they are still going their p.f is really terrible.The named ones I have are miles better.
Please resume making videos about how to undervolt them to last longer, and maybe also try fixing a broken LED lightbulb and see if it's possible or not, and maybe also show us how we could get a few lightbulb sockets and modify a lightbulb power-plug (like the pink one you have in some other video, for example) to have multiple undervolted running in parallel to get the same amount of light as a 150W incandescent lightbulb or a total of 2600 lumen or 27 W of LEDs running at their most optimal conditions.
In particular, repairing broken LED lightbulbs could be a great way to get people to start repairing electronics. First a lightbulb repaired, then making a lightbulb-bouquet to get the same amount of light from multiple undervolted lightbulbs which would last forever, then repairing some other device which is already broken, then moding some other device to run more efficiently or to last longer, then repairing broken headphones by replacing the wires with thicker wires which lasts longer, then cutting an USB/HDMI/DisplayPort/Thunderbolt/ cable and connecting the wires (maybe except the power wires, if you have a powered USB hub which to use on the side at a distance from the device using it) to those of an ethernet cable (RJ-45 cat 5 or cat6 or cat6e or whatever else, or even telephone/landline wire which is either RJ-10 with 4 wires or RJ11 with 5 wires) to increase it's range from the 5 meters maximum of USB, to maybe not the full 100m of an ethernet cable, but likely at least 50m (1m is close to 1 yard, or triple the number of meters to get close to the number of feet), then even more advanced things.
If you ignore the 8 power pins of the 24 pins of USB-C cables (i.e. 4 outer pins are ground, and the 4 pins which are 4th from the outside to the inside and which have 5V of power), you can get 2 USB-C cables (16 pins each without power, but they are in pairs of 2, so 8 wires each USB-C cable, more specifically pins 2,3,5,6,7,8,10,11 from any side) extended through 2 RJ-45 ethernet cables each (with 8 pins and 8 wires each cable), so you can have one USB-C cable for a screen and another for an USB hub for peripherals, so you can control your PC from a different room or form multiple rooms at the same time. So you could have a pseudo-laptop terminal on a folding table into your bathroom, so you can sit on the toilet and watch youtube videos or something. HDMI has 19 pins and DisplayPort has 20 pins, so you could also include the power pins of the two cables. Even with USB-2, which has 9 pins, might be enough for a mini keyboard with an included touchpad and optionally also a mouse.
A toilet roll works well as a holder if you're soldering on it (the lamp).
The 12v DC bulbs can have their resistors shorted (1 per 3 LEDs on the ebay bulbs I've seen) and then run off a buck converter which also makes it dimmable.
Just remember not to plug them into the mains. (Assuming using E27 or B22 corded lamps with mains plug.)
Clive, many thanks for your work in this area! I have an application in my midwestern USA home with two indoor flood lights configured as downlights (bases up). The kitchen is about 4 years old and I've had to replace each of the lamps (best I could buy–GE Reveal, 90w) FOUR TIMES! They work for the majority of the year and then most often go to pulsing on and off with a duty cycle ranging from a couple of minutes all the way down to 30 seconds or less. I've taken them apart and the failure has always been in an individual LED chip. I've always thought the problem was heat related and have tried drilling holes in the case to introduce a chance for less heat pooling up around the lamp's PCB (base up, remember). After the bulb has been illuminated for 30 minutes, it really is getting too hot to touch in there. I've contacted GE about the problem and always get a kindly sounding voice that profusely apologizes, sends me a couple of coupons for replacement lamps for my trouble, but "no, we know of no general case problem with these lamps."
Your work opened my eyes to the REAL issue here–it's not really a heat problem, per se, but one of pushing too much current thru those LED modules! I'm of a belief at this point that running the PCB naked (without baffle, base or additional cooling) would still result in the same problem eventually–the LEDs are cooking until they fail internally!
So, anyway, using your exploration as a starting point, I opened up two new GE basic indoor floors and although the circuit design is different than what you demonstrate in this video, it wasn't hard to find two PCB resistors in parallel draining a little controller to ground. I scraped off the smaller of the two, as per your experiment and total wattage in the lamp went from 13W down to 6, which means each of the 30 LED chips went from almost half a watt down to below a 1/4 watt! Reduction in light was certainly noted, but hardly enough to worry about (my guess is 10%?). I went ahead and drilled a series of 1/4" vent holes high up in the base, just down from the screw base, just for grins.
Anyway, thanks again! I'm pretty confident that I'll be buying far, far fewer LED bulbs in the future. I'm going to now routinely modify all LED bulbs as per the "Clive Protocol!"
I'm curious. When you remove the resistor, does the light output decrease, say 100w output becomes 60w output for example, or does it remain at 100w?
Just a normal viewer, I am thinking that this design with a PCB was designed to intentionally be overpowered and have the least amount of material to dissipate heat. They are pushing way too much power to each LED which in turn makes them hotter and burn out quicker than the design states it should on paper. Since they're in a series a normal homeowner will just throw out the light bulb and not deal looking for a solution to dim or flickering bulbs.
I definitely am more interested on the technical side for sure. So, this is helping tremendously. What would your opinion be a bulb like (SYLVANIA LED TruWave Natural Series)
I did it to a 4W – 5 Leds. I replaced the 2.4ohm resistor for a 4.3ohm since some has just one resistor. So now it's about 2W and just soft warm. Eventually I will do this to all my lamps. Thanks for the calculations.
I was trying to find constant current Linear LED driver for my custom pcb led light im making, and came across the 'AL5890' it has a fixed current from 10 to 40 ma, i think it has the resistor built into it, so you cant change the power, only if you wire them in parallel.
.. that is correct.. chip 2835 is only 0.5w and have not encountered a 3 strip internal to make it 1.5w.. 🤔🤔
I swear… All the LED bulbs we have here in the US have power supplies with isolation transformers. Very different then the simpler ones you have in this video. Makes them much more difficult to reverse and modify…
I was reading through the datasheet for SM2082 and it looks like most of these cheap bulbs are also running these ICs (not just the LEDs) beyond their absolute maximum current ratings. And the maximum output current for these chips is 60mA. I can bet my bottom dollar these LEDs take around 75 mA when they are run at 0.5W each (at least for 5730 LEDs, these looks like 5050s). And they have an absolute maximum of 150mA for short periods and a 120 mA drive current with proper heat sinking. The Datasheet recommends that these ICs can be connected in parallel with individual sense resistors for applications that need more current than 60mA. So, even with your "hack" the ICs are running out-of-spec and may fail before the LEDs.
EDIT: Okay it looks like the Vref i.e. the sense voltage is set to 0.6V internally. So a 30ohm resistor will only be getting 20mA of current in this circuit. That is well within the operating range for these LEDs and the IC. (I think these are 5050s and the Max forward current is 60mA) So, Clive these look like they are designed under spec. The wattage you get is with the efficiency loss of IC. (I think the IC dissipates excess power as heat and that is why the wattage is so high. The datasheet specifies that if the "total" bias voltage of the LEDs is closer to input voltage the efficiency factor will creep closer to 1 ( Which makes sense as this is essentially a resistive limiter). So you are wrong in the video, the IC takes the brunt of the load and my initial guess was correct, you are not saving the LED by current limiting, you are saving the IC as running a lower current means that there won't be too much excess power that would need dissipating.
(For the 5 LED bulb in your video, it was taking close to 6 watts, but it was using less than 1/3 W of that power for the LEDs themselves. So the IC is dissipating more than 5 W of power, the design is very inefficient.)