Power Distribution

[oxytousc]

I’m building a power injection box for my megatree. I plan to inject at the end of each run of 400. My plan had been to use a separate psu at each drop, but now I’m realizing that idea is probably not electrically sound. Correct me if I’m wrong. I guess I could try to use a power balance cable, to provide essentially injection on the backend, since it’d be from the same PSU. My other option would be to put a power tee at pixel 200, since they’re 200 up and 200 down per controller port, but then I’m going to have to run 26 power drops up a 17’ tall megatree, which seems dumb. I think the power balance is the best option. But let me know if there’s a better mousetrap.

 

[merryoncherry]

What voltage and pixel design? Can you describe the power supplies?

 

[Indigogyre]

So, if you have not already pushed all your pixels into the megatree strands yet I like alternating nodes up, and then come down once more. This puts the input and output at the bottom to make these things easier. We'll wait for more electrical details.

 

[oxytousc]

What voltage and pixel design? Can you describe the power supplies?

It’s all 12v. I’m going to use Matto’s evo pixels. The spacing is such that it’s 200 pixels up and 200 pixels down. It’s a total of 56 strands. Rather than splitting the tree across controllers, I’m planning to use 26 ports on an experience lights 32 port genius pro. That board has 4 separate 350w meanwells. So each psu will power 2600 pixels. I built out a power injection box with another 4 350w psus. I’d planned to do 26 power injections. So each string of 400 has a power feed from the controller and then I’d have another inject at the end of the run that would come from a different PSU. I’m realizing somewhere on each run of 400 I need to disconnect the V+ coming from the controller. As I’ve thought about it more, I think my plan will still work, I just need to get a no power pass through to go between the first 200 and second 200 to disconnect the V+.

 

[oxytousc]

These are what I need:

No Power Passthrough xConnect Pigtail 5 Pack

Min Qty: 2 These 8" connectors are used to separate power supplies on the same strand of lights. You can put these between 2 strings of lights that you want to share data but not positive power. V+ does not pass through while Data and the Negative lines do pass through to the next string.

wallyslights.com

 

[oxytousc]

So, if you have not already pushed all your pixels into the megatree strands yet I like alternating nodes up, and then come down once more. This puts the input and output at the bottom to make these things easier. We'll wait for more electrical details.

I see what you’re suggesting. How do I change the xlights model to reflect that? Do I have to it by hand? Have to imagine there’s a simple trick.

 

[oxytousc]

I see what you’re suggesting. How do I change the xlights model to reflect that? Do I have to it by hand? Have to imagine there’s a simple trick.

That also solves my power injection issue, as I can just throw a t there.

 

[merryoncherry]

OK, so 200 pixels 1" spaced is 17'
I would strongly encourage you to consider @Indigogyre's suggestion of going up the strip at 2" spacing, then turning around and filling in the alternate holes on the way down, and back to power balance point. This will ensure the pixels are within 100 of power (200 between balance points, which is within the suggested 250 for EVOs). 400 between power points is outside the guidelines.
400 EVOs per port may be within the guidelines without any additional power need. If you need additional power, you'd be putting it between strings of 200.
I may not be following the math completely... it seems to me that 56 strands would be run off 28 ports of the controller.
The Genius Pro supports LRS-600s, that could be a better option than cobbling something strange together to get more amps. Assume you will power 3200 pixels off the same 8 ports that go to a PSU, 8mA each is 26A, the LRS-350 is good for 29, so there'd be a smidge of headroom with the regular LRS-350.

 

[merryoncherry]

I see what you’re suggesting. How do I change the xlights model to reflect that? Do I have to it by hand? Have to imagine there’s a simple trick.

There's a tickbox called "Alternate Nodes" for it.

 

[oxytousc]

OK, so 200 pixels 1" spaced is 17'
I would strongly encourage you to consider @Indigogyre's suggestion of going up the strip at 2" spacing, then turning around and filling in the alternate holes on the way down, and back to power balance point. This will ensure the pixels are within 100 of power (200 between balance points, which is within the suggested 250 for EVOs). 400 between power points is outside the guidelines.
400 EVOs per port may be within the guidelines without any additional power need. If you need additional power, you'd be putting it between strings of 200.
I may not be following the math completely... it seems to me that 56 strands would be run off 28 ports of the controller.
The Genius Pro supports LRS-600s, that could be a better option than cobbling something strange together to get more amps. Assume you will power 3200 pixels off the same 8 ports that go to a PSU, 8mA each is 26A, the LRS-350 is good for 29, so there'd be a smidge of headroom with the regular LRS-350.

Meant 52 strands.

If I put power at 400 feeding back pixels 400-201 on one PSU and pixels 1-200 fed off the port with a data only connection from 200-201 connection, isnt it the same net effect as putting the power at 200 feeding 201-400?

And, yea, I might be able to get 400 fed without power and only power balancing. Need to get them in hand and test it. I could also use the in line power balance and have it fed at 200 if needed. But, I guess the point is I probably don’t need to truly inject.

I’ve got an injection box built regardless at this point, so that work is done. So I’m covered either way.

 

[Skymaster]

If I put power at 400 feeding back pixels 400-201 on one PSU and pixels 1-200 fed off the port with a data only connection from 200-201 connection, isnt it the same net effect as putting the power at 200 feeding 201-400?

Yes and no.
From a pixel to power source perspective yes.
From the fact you only have one power cable back to the controller - no. The length of your lead-in to the strands would also come into play; and have double the voltage drop with the former (single) connection.

 

[fugley]

So, if you have not already pushed all your pixels into the megatree strands yet I like alternating nodes up, and then come down once more. This puts the input and output at the bottom to make these things easier. We'll wait for more electrical details.

Thank You Very Much ! this fixes a silly sized tree 24/150 i was planing which leaves the end of the string at the top of the tree
now reminding me of this it'll bring the end back down to the ground

 

[oxytousc]

Yes and no.
From a pixel to power source perspective yes.
From the fact you only have one power cable back to the controller - no. The length of your lead-in to the strands would also come into play; and have double the voltage drop with the former (single) connection.

Oh, so basically I’d have the voltage drop at 201-200 if I inject at 400 instead. I could still inject at 200 if needed or try in line power balance which might be the better ticket if I’m thinking about it right. Basically break of the 12v power and ground lines from the port line and tee them off to 200-201. And then I don’t have to run any separate PSUs.