WS2812B multi-controller power and warm wire issue

I have multiple WS2812B stips (24 LEDs per strip) configured to function using multiple data pins of an Arduino 2560 Mega and an external 5V 2.5A power supply. The multiple controller setup and multiple data pin use was done purely because of the physical wiring needs, nothing more.

I elected to use 1-2 meter CAT5 cables to connect each LED strip.

Although it is possible to illuminate multiple strips at a time, I am not doing that. Some or all of a single LED strip are lit at any given time but all other strips are set to CRGB::Black.

I should also mention, I set ALL LEDs for ALL strips to CRGB::Black during setup().

Power requirement of each LED strip = 24 LEDs @ 60mA = 1440mA or 1.44A

I'm finding I can surprisingly connect and illuminate a single LED strip but cannot connect multiple strips even if all LEDs are set to CRGB::Black. I would have thought I could hook up 100 LED strips as long as they were set to CRGB::Black.

So I hook up 4 strips using an external power adapter. Insofar the adapter does not have full Amp capacity to handle 4 strips (96 LEDs) my code works without issue.

The issue I seem to have is the CAT5 wires get hot even if the LEDs are NOT illuminated (i.e. LEDs are set to CRGB::Black)? Sup with that? Why would the LED strips draw any power when set to CRGB::Black?

I appreciate any insight.

Part of the WS2812B LEDs is a 'driver' that consumes power, even of the LED itself is off.

Cat5 is not made to transfer power, make sure you use proper size cables for all your connections.

Ws2812 draw about 0.5~1mA per led even when off. With 24 LEDs in a strip, that should only be 15~25mA and I wouldn't expect that to cause much warming even in thin wires. Measure the current that is flowing in the cat5 wires when they get warm and check how much current actually flows.. Maybe there is a short somewhere and the current is much higher.

I elected to use 1-2 meter CAT5 cables to connect each LED strip.

Are you using a single conductor each for 5 volts, data, and ground? With eight conductors, I would try running three in parallel for 5 volts, four for ground, and a single data, making sure that the wire paired with data was a ground. (probably a good idea to pair a ground with each 5 volt also).

PaulRB:
Ws2812 draw about 0.5~1mA per led even when off. With 24 LEDs in a strip, that should only be 15~25mA and I wouldn't expect that to cause much warming even in thin wires. Measure the current that is flowing in the cat5 wires when they get warm and check how much current actually flows.. Maybe there is a short somewhere and the current is much higher.

This makes a lot of sense to me and measuring the load is definitely in order. Should have done that already. But it's helpful to know the LED driver draws 0.5~1mA in an off state.

For prototyping, I have a single CAT5 strand connected to the power supply which I then insert into a breadboard. Then I split the power in parallel to each LED strip. It's that single strand that is warming up. What is interesting is a single CAT5 conductor is rated for 577mA (Category 5 cable - Wikipedia).

I'll circle back once I measure the draw. See if I'm missing something.

I appreciate the feedback.

david_2018:
Are you using a single conductor each for 5 volts, data, and ground? With eight conductors, I would try running three in parallel for 5 volts, four for ground, and a single data, making sure that the wire paired with data was a ground. (probably a good idea to pair a ground with each 5 volt also).

Each LED strip has the 5V and ground running in parallel. Each strip also has a data conductor running back to a different digital pin on the Arduino. I think my issue might be my setup. I have a single CAT5 strand connected to the power supply which I then insert into a breadboard. Then I split the power in parallel to each LED strip. It's that single strand that is warming up. Gotta check the load.

Thanks for the suggestion.

A breadboard is not designed for higher currents.

Doesn't explain the warm cable though.

grandmastert:
It's that single strand that is warming up.

Even powering 4 strips at 25mA each when the leds are off still isn't enough to cause warming.

Case closed...

I sometimes think I'm better than I am but paying attention helps. The CAT5 conductors were not my issue however feeding the power on a single conductor into the breadboard and subsequently back out, was. Running parallel power directly from the adapter to the LED strips work as expected.

Had some noob wiring issues with the LED strands too.

Thanks for the feedback.