I recently purchased one of these LED strips. Now I have read all about how these are notoriously known for drawing a lot of current from its power supply so I bought one of these power converters thinking I would have more than enough power to sufficiently supply the strip. The converter is wired to a 12v power source.

However, when I set all of the LEDs in the strip to full white at max brightness I see a reddening of the LEDs as you get closer to the end of the strip, indicating to me that the blue and green diodes seem to be dimming and therefore not receiving enough power.

I then measured the current using a multimeter and discovered that the strip was only drawing around 4.5 amps when in reality it should be drawing around 9 amps. This was calculated based off of 60mA per LED at full brightness from Adafruit's guide to powering the WS2812B's and other research I've done.

In essence, the LED Strip is only drawing 4.5 amps when it should be drawing nearly 9. Any ideas on why this might be? I am also controlling the LEDs using an Arduino Uno.

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    \$\begingroup\$ Have you tried calculating the voltage drop across the strip of LEDs? At the far end, your 5V rail is probably dropping considerably below 5V. This is likely why you are losing the higher voltage blue and green components. \$\endgroup\$ Commented Feb 19, 2019 at 15:27
  • 2
    \$\begingroup\$ I would agree and propose you measure the voltage at the end of the LED strip. \$\endgroup\$
    – Codo
    Commented Feb 19, 2019 at 15:32
  • 1
    \$\begingroup\$ I posted an answer, then noticed you'd already linked to the same reference. Just follow the recommendations there about adding taps into the power lines every meter to hold the voltage up. \$\endgroup\$
    – Phil G
    Commented Feb 19, 2019 at 15:53
  • \$\begingroup\$ An option to simply balance the load to the LEDs is to attach power and ground to opposite ends of the strip, or if multiple taps are needed, to alternate them, IE attach power at 0m, 1m, 2m, 3m and attach ground at 0.5m, 1.5m, 2.5m, 3.5m for a 3.5m strip. This will reduce the necessary wire size slightly, or optimise performance for a given wire size. \$\endgroup\$
    – K H
    Commented Feb 20, 2019 at 1:10

1 Answer 1


Check the voltage on the far end. Your LEDs sound like they're not being supplied with sufficient voltage, and it may be that the current you're supplying right now causes a sufficient drop by the end of the string. 4.5A is a lot of current for a system like that to handle and it's likely there's a significant voltage drop along the LED strip.

It appears the strip may not be designed to supply current along its whole length while every light is at maximum brightness.

I'd start by supplying the 5V and GND to the center of the strip so there's half the current on the board running in either direction and so the strip runs half the length from where you connect it to the end. Then measure the voltage at the end and if you need you can add secondary connections to deliver 5V to the portions of the strip that are falling below the 3.5V VDD minimum specified for the LEDs, you can make more connections to VDD and to GND to bring that region of the strip back to a 5V supply voltage.


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