RGB LED strip misbehaviour

Other Hardware LEDs and Multiplexing
1

I have an 11m strip of 3528 RGB LEDs made up of two 5m segments and a 1m segment joined by solder traces, with connectors at each end.

When I apply 12V to either end, the LEDs closest to the supply are fine, but as you move down the strip every 2nd group of 6 LEDs starts to fade (first blue, then green, then red then all) to the point where at then end of the strip, every second group is not lit up at all.

Same phenomenon occurs regardless of which end you supply power. I took voltage readings at the two joints and get somewhere between 6-9V depending on the colour. My 12V supply outputs around 12.5V under load.

The perplexing part is that every 2nd group of 6 seems to be fine. I looked for a schematic to figure out how things were laid out but had no luck.

Any thoughts or direction on other troubleshooting I should do?

2

Hi, use some good quality thick gauge wire to separately carry power from the PSU to the start of each section, and ideally the end of the last section also. That way, you are not relying on the thin conductors in the strip to carry what will be quite a lot of current. Thin conductors + high currents = big voltage drop!

Paul

3

PaulRB:
Hi, use some good quality thick gauge wire

That is to say - power cable - like you use in the house, either in the house wiring, or what you would use to connect a heater.

Or even better, heavy automotive cable (you do not need the insulation thickness, but you do need the conductor thickness).