Power injection problem

Nick Cosper

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Sep 24, 2013
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26
Can't seem to figure this one out.
I am running some 12vdc pixels, three LED's per pixel and I cannot get the power injection to not mess up the display. The pixels are ws2812's, three wire. Some are rectangular pixels some are 5m strips. I have the common pigtails that holiday coro/Ray wu sells along with the T's for power injection.


When I run power to the middle of a string the pixels going out from that point go screwy, flickering and staying on all the time. After about 30 pixels the rest of the lights will work well. If I run it to the end of the string it seems to work fine as long as the string is very long, like 2+ full 5m strips connected together. When I run these through the 3 bulb rectangular pixels the voltage drops out after about 50 pixels and the remaining lights stay off. On those if I inject at the end the entire string turns off. I can get them to work by cutting the power that is going into the last 30 pixels and leaving only power going into the end but it seems as though I occasionally get a bulb stuck on or something strange.


I have tried injecting power with different 12 v converters, the same on that is running the controller, short runs of wire, long runs. I seem to get the same results with them all.
I have a bunch of 5v strips and I've never had any problem injecting power to them, the 12v just don't seem to want to cooperate.
 

AAH

I love blinky lights :)
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I would check that the T's in particular don't have something screwy happening with them. The very 1st one of these that I touched had an internal short. Using another T immediately beside your injection point would allow you to measure the voltage with a multimeter to check that you are getting 12V or pretty close to it.
Do you want to elaborate on what you're meaning by different 12V converters. I can't work out if you're meaning different 12V power supplies or a 24->12V buck converter or similar. A drawing of how you're connecting things up may help as well.
 

Jamie

Lighting up the night.
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At the bris mini this year superman had some of these t connectors- all of which had failures.
 

Nick Cosper

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Sep 24, 2013
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By mentioning different 12vdc converters I mean that I have 4 of them, one runs half of my ecg p12r board, another the other half. I have some long runs so I also have a couple closer to the strings for power at the ends of those.


I was suspecting the t connectors also. I just connected one by simply putting it in between two connectors and leaving one of the ports open. Then swapped out the on e open one to make sure that one port didn't have a failure. When I did this I didn't see any issues with the end results. I guess it could be the connector still but it didn't fail by using it inline on the in side of the connection.


I'll see if I can draw up the wiring, but overall its very simple. 3 3m strips, connected at one end from a ecg p12r. Between strips I have connectors and when using a T it messes up the next 10-30 pixels.


The other pixels are a bit tougher to explain so I'll try and draw it up.
 

Nick Cosper

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Sep 24, 2013
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Here is the diagram. One thing I forgot to add is power injection is run from the same power transformer as the controller. I've tried a second transformer but results were the same.
 

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starzen

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Oct 13, 2012
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definitely check all the plugs and esp. the Ts that they are wired correctly. I always measure every one with a multimeter to make sure the correct wires are connected and that there are no shorts. I just use two known good plugs (one female one male) and plug the new one in and measure between all the wires. only the same color set should have connection
 

Nick Cosper

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After some trial and error I had all but eliminated the t's as the problem because I could reproduce them with just regular connectors for what I showed in the diagram. Today I decided to skip all plugs and just straight hardwire it. Same problem. Out of frustration I decide to swap the wires going to the power transformer and whalla.... it works. I then go back to the last pixel and the stupid this is cross wired. All that frustration and it was just wired wrong... All figured out at least but learned a lesson not to trust that the lights are wired properly.
 

fasteddy

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Great you found you issue, never trust the wiring colours, ive had strings from ray where the colour of the wires crosses over 1/2 way through a string. But it was a good learning for you.
 
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