I have 3 RGB LED strips which are controlled by an infrared sensor input. The way they are working right now is that there is one 12 V, 3 A adapter that powers one LED strip. I have connected all 3 strips in series. Now the problem is that the brightness of the LEDs is decreased in the 2nd and 3rd strip. I don't want to use separate power supplies to power each strip. Can I use a 12 V, 5 A adapter to address this issue? Or is there any other good solution for this problem?

  • 5
    \$\begingroup\$ You can use one power supply but feed strips with separate wires. Star connection, not chain. Your current problem is voltage drop inside the strips. Controller has a switches, you should check if they can transfer enough current. \$\endgroup\$
    – user263983
    Commented Mar 23, 2023 at 14:40
  • \$\begingroup\$ Homogeneity in brightness pretty much depends on current, which in turn depends on voltage. If the strips form a loop, leave it open and connect one rail from one end each. \$\endgroup\$
    – greybeard
    Commented Mar 23, 2023 at 15:04

1 Answer 1


A larger power supply may help, but it isn't really the problem.

The power to the LEDs is carried along thin copper tracks in the flexible circuit board strip that the LEDs are soldered onto. Those strips have a small resistance per metre. As you string more and more LEDs together, the total resistance gets higher, the voltage at the far end gets lower, and the LEDs start to dim.

The solution is to run additional wires to carry the supply to each strip.

There are various ways you could do that. Perhaps run separate wires to each strip from the power supply. Or run extra wires to the far end of the last strip, and feed the LEDs from both ends.


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