First LED of Neopixel SK6812 LED stripe dying on power off/on

Hello everyone,

in my current project, I'm controlling a SK6812 LED stripe having 300 (- 1 :frowning: ) LEDs using an ESP32 (Lolin D32).

The setup is quite simple: The 5V Power is supplied by a 100W Meanwell LRS-100. Using an LDO to get the 3.3v for the ESP32 and controlling the stripe using these 3.3V (I know this is not ideal, but it seems to work without a level shifter). The stripe itself is powered directly from the power supplier. Since I had some flickering towards the end of the stripe, I am now powering the stripe from both sides and using the same power supply. Parallel to the supply I have added a 1000 uF cap as suggested by some manuals.

Now, already two times when I unplugged and replugged the power supply from 220V, my first LED in the stripe died such that the whole stripe does not work anymore until I remove the first LED.

Do you have any Idea what could be causing this and how I can prevent it from happening.

I have already measured the power supply which delivers 5.1v

Well, we are going to want photos of how you have actually wired the main parts together, and particularly the ground wires.

Thanks for your answer. I hope this photo is detailed enough. If not, let me know what else you need to know. The blue header (5V input) on the PCB is directly wired to the white header. The white header has an additional data pin and goes to the LED stripe.

I think you should insert a resistor into the data line,
you can find details about the value in the Adafruit documentation,
but 330 (IIRC 200) Ohms should work in protecting the first LED from being powered via the input pin.

OK, now you have the main power and data connected to opposite ends of the strip. That is clearly wrong to start with.

While it is true that power (two wires, 5 V and ground) should be connected to both ends of the strip (as well as in the middle), the power cable should go from the power supply directly to the start of the strip, then follow the strip along to the middle point where it splices in and from there also following the strip to the "far" end.

The power should then also go from the start of the strip together with the data wire, back to the controller.

Thanks, this could very well have been the problem. Since adding the resistor, no additional LED died. So three casualties because of me not RTFM carefully enough. Thanks for your help.

now you have the main power and data connected to opposite ends of the strip

Both sides of the strip are powered with the same 5V. The power for the start of the strip is just routed straight through the PCB without any components in between. This was just to let me have a single 3-pole plug for the strip (my first approach was to power the strip only through the start).

the power cable should go from the power supply directly to the start of the strip, then follow the strip along

Do you mean physically follow the strip? This would make the power cable much longer and more complex to guide.

to the middle point where it splices in

I don't think my strip is intended to be powered somewhere in the middle. It has an IP65 protected (which I don't need) and powering it from somewhere in the middle would mean to void this protection.

In any case, thanks for your help. My goal is to learn something new with this project and It's probably not the last LED strip I have used.

I fear this was too early :frowning: Again a LED died. Do you have any other suggestions what might be going wrong here?

OK, on a closer look at the picture I see there are all three connections there.

The "IP65" refers to waterproofing but clearly no other part of your assembly is in any way whatsoever waterproof. :grin:

Two significant points: The foils on the strip acre clearly not capable of carrying 8 Amps (from each end) so at full white you will get yellowing in the middle of the strip. This may not be a problem to you.

Large loops in the wiring - and you do have a large loop in the power wiring - may permit coupling of transients between one part of the system and another. Probably not going to be too much of a problem there, but best avoided where possible. It would be preferable to keep all the wiring together.

Oh, that's sad!

Possibly what I first recommended? :roll_eyes: Note the part about supplying the processor board back from the start of the LED strip, not supplying the LED strip through the processor board.

Thanks for the further explanation. No, the whole system is not waterproof by any means. I just bought the IP65 version of the strip since it was on stock an even cheaper than the alternative.

The 8 AMPs will never be reached. I'm using less than every second LED which should then be less than 4 AMPs from each end. Also full white is not really a use case.
Its basically this clock with some modifications:

I am now using one LED to act as a level shifting for the data:

Also, I have reworked the wiring and reduced the power supply from 5.1 to 4.9V. Let's see if the LEDs will survive now.

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