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Thread: Am I pushing my luck?

  1. #1
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    Default Am I pushing my luck?

    5v ws2811 bullets. Mega tree has 50 per string @ 16 legs. Doing some calculations on the power injection calculator working with the rule of thumb that you generally Inject e we 50 with 5v. But I would REALLY like to avoid having 16 or whatever injection points x2 for the v-.. That's an extra 32 wires. Eyesore, pain in the butt etc.... I'm running it as 4 blocks of 4, so every block of 4 strings has its own output on the controller, and the controller will be located just above the topper on my second floor deck. If that helps anyone visualize the setup. So I was tinkering with the calculator, seeing how far I could push it. These are mostly 24 awg pixels fyi. I tried running Injection at pixel 0, 100 and 200, with 18 awg, 5' lead wire power restricted to 50%. That tells me my lowest drop would be around 4.4v, and if I increased the lead wire to 16 awg under 5', supposedly I drop to 4.49v max. I'm hearing pretty wide ranges of what's ok out there, some people saying you can't drop lower than 4.5-4.7 without negative effects. Others giving it a bit more into the 4.2-4.8 range. Is it feasible to run that every 100 injection as outlined above without noticeable side effects at 50%? Or is that optimistic? I'm also very interested in any feedback on the best way to efficiently inject my particular layout if it was your setup. (keeping in mind the plan is to have the e682 controller on the deck about 6" above and behind the topper, but I can always move it if there's a good idea)

  2. #2
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    Default Re: Am I pushing my luck?

    I have a similar setup but power from the bottom. In your case things are simpler (yes you need to make 32 solder connections but that is just the way it is), your PSU is up on the deck, hopefully in the same box as the controllers. That means you have less than 1m from the PSU to the top of the tree. A bundle of 16 power cables from the PSU to the top of the tree should be easy to manage. Hide it with garland. With only 50 pixels per leg you do not need to run the power cable anywhere except to the top of the tree.

    Next lets do some power calculations (I always plan and design for 100%), 50 5v pixels = 0.06a * 50 == 3A. A 16 AWG wire at less than 1m can handle 12A.

    This means you can inject four legs using a single 16 AWG power lead. The result would be four cables from the PSU to the top of the tree and each power cable gets connect to four legs. While this reduces the number of power cables, it increases the mess at the top of the tree.

    If you insist on calculating for 50%, then you could reduce the power cable size to 18 AWG or double the number of legs connected to the power feed cable. I would not do this but this is DIY.


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  3. #3
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    Default Re: Am I pushing my luck?

    I have a 16 leg 50 pixel Mega tree that is 5v. I am running them all off 1 port and I power inject at the bottom of ever other leg so every 100 pixels. My injection wires are 18 AWG and probably 10 foot long, and I inject at the end of 16 as well. So 8 injection points. At 100% white the color is a little off but with the power down it works with no issues. All other colors were fine at 100%.

    --
    Shawn

  4. #4
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    Default Re: Am I pushing my luck?

    Quote Originally Posted by sctwohig View Post
    I have a 16 leg 50 pixel Mega tree that is 5v. I am running them all off 1 port and I power inject at the bottom of ever other leg so every 100 pixels. My injection wires are 18 AWG and probably 10 foot long, and I inject at the end of 16 as well. So 8 injection points. At 100% white the color is a little off but with the power down it works with no issues. All other colors were fine at 100%.

    --
    Shawn

    So you are saying that basically exactly what I said, inject every other leg/100 pixels, but not even reduced to 50% power is more of less working fine for you?

  5. #5
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    Default Re: Am I pushing my luck?

    Thanks for the feedback so far. So to clarify, my psu is in the same box as the controller. I have always run it from the bottom of the tree, but I had thought it may be worth trying it from the top deck this season, because it would allow for shorter runs for other props to connect to the controller without long extensions. This however, is not set in stone. I was planning on running some injection wires from the psu in the controller box, but seeing as I have multiple other props connected to the same controller and psu, I was pretty resigned that I would have to use standalone power supplies for injection, which obviously does not allow the two different v+ sources to interact

  6. #6
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    Default Re: Am I pushing my luck?

    problems come when you do all strings 100% white.
    i have never wanted to have my tree go 100% white in anything i sequenced.
    strings on the house i want to do 100% white but never my tree

  7. #7
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    Default Re: Am I pushing my luck?

    I ran 100% 2 years ago, and it worked fine. Last I reduced the power down to 50%, and you couldnt really tell much of a difference other than whites all looked white with the reduced power.

    --
    Shawn

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