Author Topic: 5a output per port, max pixels, etc.  (Read 280 times)

Offline gspence1@gmail.com

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5a output per port, max pixels, etc.
« on: December 04, 2018, 11:54:44 PM »
I just wanted someone to confirm my math or correct me if I'm misunderstanding. 


I just purchased the F48 and the specs say it can support 16384 pixels. That works out to about 341 pixels per string.  (16384 / 48)


However, the board says that each string output is rated at 5 amps.  If a typical 5v pixel is 60 mA when powered on as white, that means you can only run 83 pixels per string on full power before you hit about 5000 mA per string. 


Unless I'm way off, or we make a big assumption that we don't run our pixels on white, how do we get anywhere close to 16384 pixels per board?  In my current display, I have several fixtures where I'm running 96-112 pixels on a single string.  Am I running the risk of blowing the fuses?


Thanks!
Greg


Offline Bwinter

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Re: 5a output per port, max pixels, etc.
« Reply #1 on: December 05, 2018, 12:04:45 AM »
Power injection

Offline gspence1@gmail.com

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Re: 5a output per port, max pixels, etc.
« Reply #2 on: December 05, 2018, 12:28:30 AM »
Thanks, that's what I am doing, I just wasn't sure how the amperage draw works if you're powering a string at both ends.  Does it pull equally?  If I have 200 pixels with power injection at the end, that's a total of 12 amps.  Would it pull 6 amps from each end of the string?


Offline jnealand

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Re: 5a output per port, max pixels, etc.
« Reply #3 on: December 05, 2018, 06:19:25 PM »
Do not confuse powering strings straight from a board output and powering separately thru a distro board.   the f48 supports controlling 16k pixels not powering.
Jim Nealand
Kennesaw, GA all Falcon controllers, all 12v Master Remote Multisync with Pi and BBB P10 and P5

Offline gspence1@gmail.com

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Re: 5a output per port, max pixels, etc.
« Reply #4 on: December 05, 2018, 06:41:36 PM »
Right. I guess I just made the assumption that the 12 receiver boards could power that many pixels, but that was naive of me. 


What power distro boards are recommended nowadays?  I know every year or two new things are always coming out.




Offline TNF250

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Re: 5a output per port, max pixels, etc.
« Reply #5 on: December 06, 2018, 08:38:17 AM »
Are you running your light at 100%? I run my at 60% and really don't see any difference in the light output.
Zane
Springfield, TN

X-Lights - RPi3 - FPP - Falcon - DLA Lynx

Offline gspence1@gmail.com

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Re: 5a output per port, max pixels, etc.
« Reply #6 on: December 06, 2018, 01:43:00 PM »
I believe I am, and you're probably right.  I'm guessing there's a global adjustment in xLights that doesn't require editing each effect?


Offline TNF250

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Re: 5a output per port, max pixels, etc.
« Reply #7 on: December 06, 2018, 02:21:18 PM »
Not each affect but there is a setting in layout in the prop under Dimming Curves. Or you can change it in the F48 if it is anything like the F16v3 in the String Ports - Brightness.




Offline Emuney18

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Re: 5a output per port, max pixels, etc.
« Reply #8 on: December 07, 2018, 04:55:12 AM »
Thanks, that's what I am doing, I just wasn't sure how the amperage draw works if you're powering a string at both ends.  Does it pull equally?  If I have 200 pixels with power injection at the end, that's a total of 12 amps.  Would it pull 6 amps from each end of the string?
The answer would be yes assuming all the lights are doing the same like a single color.  Think of amps/current like water and it might help you make sense of it.

Light strings are a hose and then attach both ends to a faucet.  If you turn on exactly same time the water meets in the middle.  If you cut some holes to represent lights at the beginning of the hose water will come out and it will be the water from the source closest to that hole.  Cut holes at the end and the farthest source feeds those holes.  Of course there is mixing in the middle of the water and current.  If your hose is too long very little water makes it to the middle. Now cut really big holes at the beginning and the vast majority of the water from the first source will go out the holes and lights/holes further down will get less water.  Depending on the hose length will determine what the middle looks like.  A really long hose and not much water will be in the middle.  Short hose will have a lot of water from the end source. Really big holes could be full white for example where as small holes are blue.  You can keep this going but I hope it helps some. 


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Offline jhoybs

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Re: 5a output per port, max pixels, etc.
« Reply #9 on: December 07, 2018, 05:00:48 AM »
Hey Greg,
To clarify, refer to my attachment.  The 2, 3 & 4 outputs from my F16v3 are shown in blue and use 3 wires.  I feed the start of each series of strings directly from the output ports.  The end of each series of strings you'll see a 2-wire feed - that is my power injection fed from a Falcon F8-distro using the same power supply as the F16.  As you mentioned, you can roughly assume that half the current will come from each side (in my case).
There are numerous distribution boards - I chose Falcons, but other vendors such as Crockett Fantasy of Lights sells them too.  In terms of the dimming curves, I'd recommend not applying the curves in xLights and instead use your controller.  That way you can adjust your brightness while out in your display without recompiling your sequences from xLights.
Jim H - Muskego, WI
Falcon F16v3, PiCap, FPPs. Lynx Expresses, xLights

Offline JonB256

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Re: 5a output per port, max pixels, etc.
« Reply #10 on: December 07, 2018, 10:17:14 AM »
As far as Power Distro boards, I like the ones that Falcon sells because of the pluggable jacks and LED fuse indicators. (if you use 24vdc, you may burn out those LEDs :( )

Other distro boards may accommodate larger gauge wires for power. Almost all use 5amp fusing.

The F8-distro boards show as "in stock"  https://www.pixelcontroller.com/store/index.php?id_category=14&controller=category


Offline KBCoggin

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Re: 5a output per port, max pixels, etc.
« Reply #11 on: December 07, 2018, 10:37:48 AM »
As far as Power Distro boards, I like the ones that Falcon sells because of the pluggable jacks and LED fuse indicators. (if you use 24vdc, you may burn out those LEDs :( )

Other distro boards may accommodate larger gauge wires for power. Almost all use 5amp fusing.

The F8-distro boards show as "in stock"  https://www.pixelcontroller.com/store/index.php?id_category=14&controller=category
I also use several of these, and they are in stock as I just received 3 more of them 2 days ago :) Very nice distro board.

Offline aknflyer

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Re: 5a output per port, max pixels, etc.
« Reply #12 on: December 07, 2018, 09:49:10 PM »
Thanks, that's what I am doing, I just wasn't sure how the amperage draw works if you're powering a string at both ends.  Does it pull equally?  If I have 200 pixels with power injection at the end, that's a total of 12 amps.  Would it pull 6 amps from each end of the string?
The answer would be yes assuming all the lights are doing the same like a single color.  Think of amps/current like water and it might help you make sense of it.

Light strings are a hose and then attach both ends to a faucet.  If you turn on exactly same time the water meets in the middle.  If you cut some holes to represent lights at the beginning of the hose water will come out and it will be the water from the source closest to that hole.  Cut holes at the end and the farthest source feeds those holes.  Of course there is mixing in the middle of the water and current.  If your hose is too long very little water makes it to the middle. Now cut really big holes at the beginning and the vast majority of the water from the first source will go out the holes and lights/holes further down will get less water.  Depending on the hose length will determine what the middle looks like.  A really long hose and not much water will be in the middle.  Short hose will have a lot of water from the end source. Really big holes could be full white for example where as small holes are blue.  You can keep this going but I hope it helps some. 


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I am sorry to differ. Your hose analogy would apply to voltage. Current is the same for the entire length of the string, ohms law. Dont believe me, measure current at any point in a series circuit and it will be the same. It is the voltage drop across the wire and each pixel circuit board that lowers the brightness at the far end pixels. That is resistance. E=I*R.  E=voltage, I=current, R=resistance. So resistance adds up over distance, reducing voltage. Sorry, I just could not let that analogy go without a bit of correction.39 yr Telecom Technician.

Offline Emuney18

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Re: 5a output per port, max pixels, etc.
« Reply #13 on: December 09, 2018, 06:09:56 AM »
@aknflyer thanks for correcting me, I can admit when I was wrong and I guess I am still confused about current.  What determines the amount of current on that string, the PS or the lights?  For a 30amp PS is it always 30 or only what the lights are asking for at a given time?


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Offline JonB256

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Re: 5a output per port, max pixels, etc.
« Reply #14 on: December 09, 2018, 06:59:27 AM »
@aknflyer thanks for correcting me, I can admit when I was wrong and I guess I am still confused about current.  What determines the amount of current on that string, the PS or the lights?  For a 30amp PS is it always 30 or only what the lights are asking for at a given time?


A 30amp PS can reliably supply up to 30 amps (well, don't push it that high for long)

But if the attached string of pixels/lights only needs 2amps, that is all it will supply. As the string needs more current, it's resistance drops and current flow increases. The tricky part when designing a Power Supply is that it should be able to rapidly supply changing amounts of current without big swings in voltage. Poor supplies will vary. Great supplies stay very steady. Even a Battery will show voltage changes with current changes.

So, as you say, "only what the lights are asking for at a given time"

 

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