MADRIX Forum • Nebula Cabling Option B2
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Nebula Cabling Option B2

Posted: Mon Jun 28, 2021 8:34 pm
by acdnrg
So I´m looking at the different cabling options shown in the manual and find B2 to be the most convenient for my setup (and my limited experience). I have two questions on this:

1.
In the left side of the diagram, there is the power supply symbol. According to the legend on page 8, this can be either a monolithic PSU that handles all supply or it can be multiple smaller ones.
If I´m going for smaller ones, is there any connection made between them?

2.
In the same scenario, Nebula is receiving power via the power supply terminal and not via strips. Can this be connected to one of the "LED power supplies" or should there be a dedicated PSU for Nebula?

Context:
My main goal is to keep things simple, i.e. no V+ connection between any LED strip and Nebula, all strips and connectors are configured in the same way. If Nebula can be powered from one of the "strip PSU" that´s even nicer, but I want this to be a dedicated line.

Current test setup:
Strips: 5m of WS2815, 12V, 150 LEDs, 45W -> 3.75A per strip (calculated value)
PSU: Meanwell HLG-240H-12A specified at 12V 16A (don´t get fooled my the model number 12A)
After measuring a single strip at full white pulling 2.7A, I feel comfortable to power 4 strips from one PSU. I rarely use full white and I rarely use longer light sequences. At 450 addresses per strip, assigning 1 strip to 1 universe is of course wasting address space, but the setup is much easier to understand, because:
1 Nebula = 8 universes -> 8 strips
4 strips per port, 1 PSU per 4 strips = 2 PSU per Nebula

This then defines a building block which can be replicated for growth. Either in one big installation or several smaller ones.

Re: Nebula Cabling Option B2

Posted: Tue Jun 29, 2021 8:52 am
by Guertler
Hello acdnrg,

1.) If you will use multiple smaller PSUs, please make sure the GND of the used PSUs will be connected but not the V+.

2.) If the used PSU is powerfull enough, you can use one and the same PSU to feed the LED stripes and the NEBULA.

By the way it is recommended to feed the used LED tape at least after every 2 to 3 meeters again to ensure the correct voltage will be applied. Of course you can use one and the same PSU to feed it but you have to think about the correct wire size to prevent a voltage drop.

Re: Nebula Cabling Option B2

Posted: Tue Jun 29, 2021 12:03 pm
by acdnrg
Spot on and ultra fast, thank you for your support.

I agree on the power injection in general, but will try to get away witha single injection point per strip in this project. It consists of aluminum profiles freely hanging from a ceiling, so additional cabling (and visually hiding it) is tricky and I´ll avoid that if possible. My first test with Nebula and single 5m/30 strip didn´t show any visible voltage drop at 5m, so it may be ok. Worst case I will need to inject at a 2nd point, but that remains to be seen. Actually, the better voltage drop performance of 12V was why I picked WS2815 in the first place. Totally different story for WS2812 of course.

Wiring: 16A -> AWG18 or less = 0.75mm2 or more. I´ll settle for at least 1mm2.

Is there was an option to upload images here, I could post a schematic.

Anyway, the support you give confirms my decision to go with madrix, that´s one of the reasons I picked Nebula over other options.

Thank you!

Re: Nebula Cabling Option B2

Posted: Tue Jun 29, 2021 2:57 pm
by Hertel
Our customers are at the heart of what we do. <3
We truly appreciate your support. We thank you!