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I am building a small kitchen for my child. For the hot plate I bought eight ws2812 led pixel rings: four with 8 leds and four with 16 leds. I soldered each two rings together so I have four double rings with 24 leds in total.

I soldered three 26 awg cables on each double ring and a JST (3 pin) on the other end to connect it to the pcb.

An esp32 will do the controlling of each double ring. The power will be supplied by a 5v 10a adapter (to esp32 and the leds separately).

I measured the amps at the power adapter and it showed only 2.5 amps even though all leds were turned on 100%.

The specs state that each led can draw up to 0,06A which results in 24x0,06x4=5.76A.

The leds will only light red when I am finished with this project. I just wanted to check the worst case scenario. Then each double ring will draw up to 0.48A according to the specs.

My questions are

  1. Why do the leds draw only 2.5 when fully white?
  2. Are 26 AWG cables (10cm each) a secure way in this setup? I really do not want the kitchen to catch fire.
  3. Should I add a resistors between data in and esp32?

Thank you very much for your help!

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  • \$\begingroup\$ 26 AWG is too small for almost 1.5 A. Measure the voltage drop across the wire, you're probably losing some voltage which is causing the LEDs to be dimmer. \$\endgroup\$ Commented Mar 12 at 21:45

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There are actually a great many variations on the WS2812, from WorldSemi and maybe there are other makers, I have not looked, but one common type is 12mA or 12.5mA (nominal) for each LED plus Iq so not so far off the number you are reading. The 20mA WS2812S, for example, is only one of many and might run too hot when mounted in a tight cluster. Some are more like 5mA per LED, plus Iq.

AWG 26 is fine for a couple A if the wire is rated for 75°C or 90°C insulation from an ampacity point of view, but you will lose a bit of voltage. If it works, then fine.

Yes, adding resistors is a good idea, especially with long and/or thin wires.

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  • \$\begingroup\$ Thank you for your help! I didn't know that WS2812 have different types and specs. I couldn't get AWG 18 wires soldered on the rings as they are to big. What do you think would be a safe enough diameter to use in my context? \$\endgroup\$
    – Gregor
    Commented Mar 18 at 9:53
  • \$\begingroup\$ I think for 10cm AWG26 is okay, but a bit fatter wouldn't hurt. \$\endgroup\$ Commented Mar 18 at 13:43

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