Capacitor for long ws2812b led setup

[nervusvagus]

I have a total of 20 meters leds setup coming out parallel from arduino, so 2x 5meter strips on 2 sides.

Unfortunately I can only power the arduino from one or two ends of the 10 meter long strips. I have a 20a and 40a 5v adaptors. I use a power rail parallel to the strips to feed power every 5 meters beginning and end of strips.

I know capacitors should be as close to the strips as possible. However in this case im powering from both ends.

can capacitors be close to the power as well, does distance have a big effect? Do using more than 1 capacitor (1000uf 35v) along the power rail help?

[Railroader]

@nervusvagus

I can only power the arduino from one or two ends

Make a drawing showing the physical piece of the story.
Those words doesn't make it clear. What is "the arduino"?
As I see it the power supplies could well be situated in the center. From there the extra rails for strips emerge.
Power 1 strip + the controller from the 20 Amp supply and 3 strips from the 40 Amp supply.

[Paul_B]

I think the general suggestion is that the 1 mF capacitor is to stabilise the supply where the data from the Arduino feeds into the strip.

This point is also where you should take the power back to run the Arduino itself - all three wires kept together as a bundle.

@nervusvagus

I use a power rail parallel to the strips

That is right - keep the wiring together, avoiding any open loops.

[DVDdoug]

@nervusvagus

Do using more than 1 capacitor (1000uf 35v) along the power rail help?

"Help" with what? From what I understand the capacitor is to help prevent glitches and it might not be required at all... Sort of "insurance". It wouldn't hurt to put one capacitor on each strip but if you don't get glitches/errors in the display I wouldn't worry.