LED color changing throughout strip, not drawing proper current

We completed our Hyperion setup this weekend and successfully implemented HDMI-USB capture on the Pi 4. However, the lights dim toward the second half of LEDs and for certain colors some LEDs in the last 40-50 shut off entirely. When displaying a white light, the lights go red toward the end. The theory is that it's not getting enough power to the last set of pixels (see count below). When displaying all red, green, or blue, LEDs respond properly, which reinforces the power consumption theory. When watching an HDMI source, all colors look good except it won't display white at the end of the string and instead displays red. If the whole screen isn't lit, all colors look accurate.

When hooked up to a multimeter they don't seem to be drawing nearly the expected current, only 50mA vs. expected 16A based on the number of LEDs in the circuit. We are using the right-angle pressure connectors in lieu of soldering. I thought this may have been a cause at first, however, we checked all connections and the issue appears to be a linear gradient across the entire strip with no discrete changes.

Circuit diagram and photos of issue: imgur.com/gallery/6zFjNxN

Power supply: 5V/20A
Raspberry PI (4B)
LEDs: 254 total (83 top and bottom ea., 44 left and right ea.)
Strip: WS2801 - https://www.superlightingled.c…r-reel-by-sale-p-157.html
Software: Hyperion.NG

Zitat von jeroen warmerdam

Hello.

I would recommend to use your 100watt PSU on everything, I looked at all your pictures and see you use a separate 5volts USB connector for powering your raspi4. Which isn't necessary. So make them one, or use the 50watts psu separate for the pi only, then ground everything together (use more ground pins on the PI 》》》 and very important!! Apply +5volts and gnd to BOTH sides of your ledstrip... and measure after that with your multimeter the voltage out of PSU 》》 not more then 5 volts dc under load. Your ledstrip should draw about 12,5 Amps with full brightness so there's still enough power for the USB port and pi.

First try measure and do this steps before you go on. Basics has to be good. Your connection overall is okay, not really clean but technically correct :classy:

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Thank you for the response. Completing the DC loop fixed the issue. I had tried that the previous day but must have had another issue going at the time.

Ya, the wires are due for some fixing up when I put everything together in a project box...I just kind of threw it together for testing. Thanks again!