Author Topic: Max wire length (extension) for RGB Pixels  (Read 13986 times)

Offline jwilliams31

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Max wire length (extension) for RGB Pixels
« on: November 25, 2024, 08:28:10 AM »
Is there a maximum wire/extension length for RGBs before power and/or signal start dropping off?  Trying to figure out the best placement for my controller and RGB elements.

First year attempting this so I'm still learning...

Thank you.

Offline jond

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Re: Max wire length (extension) for RGB Pixels
« Reply #1 on: November 25, 2024, 11:18:58 AM »
Lots of variables...  5v/12v, gauge of wiring, round/flat cable, how many lights, type such as seed/bullets.

I usually keep my strings under 170 lights, only run 12v lights, and use high quality 18 gauge wire.  I prefer to keep extensions under 25ft, but it does not scare me to go up to 35ft.  I have a couple of "tune to" signs with 50ft extensions and they work fine, but those are pretty far out and I am pushing it.   

5v will not go as far, but I don't use 5v lights and can't give you any recommendations.

Offline jwilliams31

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Re: Max wire length (extension) for RGB Pixels
« Reply #2 on: November 26, 2024, 08:52:04 AM »
Sorry. Some details:

12v bullets (2811 pixels)
18 gauge 3-wire for RGBs (from Amazon)

I was trying to run about 300 pixels per string.  It seems to work with 300 with about a 10ft extension, but that's just running the controller test sequence.  I haven't actually tried to run a program yet.

I will try to keep it under 25ft and keep my fingers crossed.  I appreciate the information.

Offline jond

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Re: Max wire length (extension) for RGB Pixels
« Reply #3 on: November 26, 2024, 09:22:07 AM »
300 lights sounds like a lot without power injection.  Turn the lights on all white, turn them up to the highest percentage of brightness you intend to run them at (30-40% is common), and take a multi-meter and read the voltage at the end of the line.  In most cases you do not want to be under 9.5 volts but lights vary.

Offline jwilliams31

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Re: Max wire length (extension) for RGB Pixels
« Reply #4 on: December 01, 2024, 09:26:43 AM »
Slightly off topic, but related.  As if it wasn't obvious pixels are new to me, I have some questions regarding power.

I was trying to get started with 1 controller with a 350w power supply.  I completely did not research the power thing, I just assumed it would power everything since that's what I'm used to with my older AC controllers.  I also got a bit ambitious with the prop I bought.  Not sure if you (or anyone else on here) has seen it, it's an arch with 3 singing bulbs in the middle from Holiday Coro.  Anyway, in total it's about 1200 pixels.  Now I know that there is no way I am lighting and powering this thing off of a single controller/power supply.

Here is my question though.  Even though this prop has a total of 1200 pixels, they will most likely never be lit at the same time.  For example, it may only be one (or 3) of the singing faces singing.  Or it may just be the arches lit.

I'm assuming that the power limitation would only apply if I light ALL of the pixels at once?  Not if only certain elements/pixels are on at once?

Per the power calculator from WiredWatts, in theory, a 350w power supply "should" be able to power ~900 pixels at 50%.  Still not enough to turn every pixel on at the same time, but possibly enough to run it in a show?

My other question is if you have any information you can share on power injection.  Like how do you house and wire the additional power supplies?

I think that at this point (December 1) I am not going to get the prop integrated into my show this year, but I'm trying to understand how this all works so I can prepare for next year and get what I need to be successful with this and other future props.

I appreciate any additional information you could provide.

Thank you.

Offline jond

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Re: Max wire length (extension) for RGB Pixels
« Reply #5 on: December 02, 2024, 09:20:34 AM »
Here is my question though.  Even though this prop has a total of 1200 pixels, they will most likely never be lit at the same time.  For example, it may only be one (or 3) of the singing faces singing.  Or it may just be the arches lit.

Your thinking is not incorrect, but what happens next year when you want all of them white at the same time?  Will you want to rework everything, or even remember they are under powered.  I personally power everything to handle full white at 70% power, and only run 30-40%.  That leaves me a cushion and I never have to troubleshoot power issues each year.  Are you trying to get by for a few days until more parts arrive, or are you trying to make this permanent?  I would do it right if you can, but you can push it if you need/want to.

I'm assuming that the power limitation would only apply if I light ALL of the pixels at once?  Not if only certain elements/pixels are on at once?

Correct, but see above answer. 

Per the power calculator from WiredWatts, in theory, a 350w power supply "should" be able to power ~900 pixels at 50%.  Still not enough to turn every pixel on at the same time, but possibly enough to run it in a show?

I run 2000+ pixels off a 350w at 30-40% power.  Depends on the lights, but would expect 900 lights to easily run off 350w

My other question is if you have any information you can share on power injection.  Like how do you house and wire the additional power supplies?


I try to keep my strings small enough I do not have to power inject.  Some models need to be power injected or the programming effects do not look right, such as long straight strings on my eaves.  When I need to power inject I use an empty controller port.  Not the cheapest solution, but I can move the model from controller to controller with ease and makes everything easy to hook up.  I basically take a 3-3-3 tee and remove the data pin from the power injection source with pliers.  Not suggesting you do the same.

There is no right or wrong answer provided it works.  Some have dedicated power injection boxes, some install power distribution boards in their controller box.  Really depends on the individual needs and preferences.  Since I rarely power inject, I would not be the best source on this.