I am using a 30V 50A power supply (KXN-3050D) as an external power source. I have an led strip with 120 LEDs.

The problem is that when I drive 50 LEDs (in full brightness and white,) the power supply provides 1A but when I want to drive more than 50 LEDs, my power supply still provides 1A and the LEDs after 50 turn yellow.I'm going to share the circuit I set up below.

How can I solve this problem?


  • \$\begingroup\$ What is the capabilities of your power supply? What is the current draw of the LED strip? \$\endgroup\$ – Puffafish Jun 24 '19 at 15:35
  • \$\begingroup\$ That power supply has a current control set of knobs. Do you have the current set down at 1A? \$\endgroup\$ – zeta-band Jun 24 '19 at 15:39
  • \$\begingroup\$ My power supply normally provides up to 50 amps. 50 LEDs draw 1A and glow smoothly.But when I turn on 70 LEDs, it draws 1A again and after 50 LEDs turn yellow. \$\endgroup\$ – bopele Jun 24 '19 at 15:43
  • \$\begingroup\$ If you power the LED strip from the other end, does the behavior change sides (LEDs close to power are white)? And what if you power it from both ends? \$\endgroup\$ – RaphaelP Jun 24 '19 at 15:48
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    \$\begingroup\$ It's probably the voltage drop within your LED strip causing problems. If you feed the power to the center of a strip of 70 LEDs you will likely be ok. \$\endgroup\$ – Jack Creasey Jun 24 '19 at 15:48

The power wires (tracks) on the LED strip have too much resistance to support that many LEDs. You should run extra power wires alongside the LED strip, and connect them at each end of each strip.

The affected LEDs appear yellow because the blue component of each LED needs a higher voltage to turn on. Taking away blue from white gives yellow.


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