First serious year - wiring diagram

[JordoLights]

Hello all, this is my first serious year. Last year I tried playing with 2x WS2812B 5V 5m strips using a NodeMCU just to see how I like it. I immediately got hooked to the hobby. This year, I have expanded my display more buy adding some props, arches, and outlines. I got myself a rPi-28D+ from Alan as I figured I can easily upgrade or add later on a controller with more outputs.

I have tried my best to do a wiring diagram of what my setup will be like. I need some overall tips/advice as I am fairly new to this hobby.

Everything is 5v.

My grey areas are (sorry if some of these doesn't make sense or if they are beginner questions):
1. Power injection - I've laid out in the diagram what/where I think is best to power inject? Is it true that I have to inject every 100 nodes/pixels?
2. What cable is best to use for power injection?
3. I set the brightness to 24% so it'll all be under 7.5A draw so to comply with the fuses on the 28D+ and power distribution board. What if I want to run it at 30% and the draw is >7.5A, do I just cut the + wire at 7.4A then start a fresh + from the PSU?
4. Instead of running multiple lines of power injections (ie. 2x to the arches), can I run 1 line to the arches then tap off to the 2 arches?
5. Is it necessary to fuse (2A) the rPi power input?

Thanks heaps in advance for your guidance and help.

 

[TerryK]

1. Power injection - I've laid out in the diagram what/where I think is best to power inject? Is it true that I have to inject every 100 nodes/pixels?
With the drive level at 24% you should be able to increase that. However most individuals design to a higher level which builds in some headroom if the drive level increases either if necessary or accidentally. It also depends if power is injected either at one (single ended) or both (double ended) ends of the string. Double ended fusing does design in possible cascading fuse failure so there are pros/cons to each approach.

2. What cable is best to use for power injection?
I suggest avoiding the CCA (copper clad aluminum) but beyond that just about anything that works with the amperage requirements and less than maximum voltage drop. I use a 2 conductor 14 AWG cable.

3. I set the brightness to 24% so it'll all be under 7.5A draw so to comply with the fuses on the 28D+ and power distribution board. What if I want to run it at 30% and the draw is >7.5A, do I just cut the + wire at 7.4A then start a fresh + from the PSU?
Keeping in mind what I mentioned for #1, with a bit of reserve, yes. I do think I would stay lower say in the 5 to 6 Amp range. Indirectly this indicates a single ended power injection scheme.

4. Instead of running multiple lines of power injections (ie. 2x to the arches), can I run 1 line to the arches then tap off to the 2 arches?
Yes but be aware of amperage and voltage drop. This typically means that secondary fusing should be implemented to prevent a downstream low current point from being overloaded. I do this; a single power injection cable to run several props and then secondary fusing to the individual lower amperage props. There have been a couple Forum Threads that have mentioned secondary fusing.

5. Is it necessary to fuse (2A) the rPi power input?
Recommended but I am more familiar with Falcon's Pi-Hat than the rPi-28D. I think it depends somewhat on if the rPi is powered through the rPi-28D or not.

Another note; you might try to not use the 2 Null Pixels, at least with the 4 meter cable. So far I've been good up to about 30 feet/7 meters give or take. You may want to plan on adding a F-Amp in the 7.5 meter cable.

 

[JordoLights]

1. Power injection - I've laid out in the diagram what/where I think is best to power inject? Is it true that I have to inject every 100 nodes/pixels?
With the drive level at 24% you should be able to increase that. However most individuals design to a higher level which builds in some headroom if the drive level increases either if necessary or accidentally. It also depends if power is injected either at one (single ended) or both (double ended) ends of the string. Double ended fusing does design in possible cascading fuse failure so there are pros/cons to each approach.

2. What cable is best to use for power injection?
I suggest avoiding the CCA (copper clad aluminum) but beyond that just about anything that works with the amperage requirements and less than maximum voltage drop. I use a 2 conductor 14 AWG cable.

3. I set the brightness to 24% so it'll all be under 7.5A draw so to comply with the fuses on the 28D+ and power distribution board. What if I want to run it at 30% and the draw is >7.5A, do I just cut the + wire at 7.4A then start a fresh + from the PSU?
Keeping in mind what I mentioned for #1, with a bit of reserve, yes. I do think I would stay lower say in the 5 to 6 Amp range. Indirectly this indicates a single ended power injection scheme.

4. Instead of running multiple lines of power injections (ie. 2x to the arches), can I run 1 line to the arches then tap off to the 2 arches?
Yes but be aware of amperage and voltage drop. This typically means that secondary fusing should be implemented to prevent a downstream low current point from being overloaded. I do this; a single power injection cable to run several props and then secondary fusing to the individual lower amperage props. There have been a couple Forum Threads that have mentioned secondary fusing.

5. Is it necessary to fuse (2A) the rPi power input?
Recommended but I am more familiar with Falcon's Pi-Hat than the rPi-28D. I think it depends somewhat on if the rPi is powered through the rPi-28D or not.

Another note; you might try to not use the 2 Null Pixels, at least with the 4 meter cable. So far I've been good up to about 30 feet/7 meters give or take. You may want to plan on adding a F-Amp in the 7.5 meter cable.

Thank you so much for your suggestions and input. I will read more on double ended fusing and secondary fusing.

 

[i13]

TerryK's points look good. One thing to mention is that in some scenarios, voltage drop can cause incorrect colours before it causes more serious problems. If you're getting incorrect colours when you turn the brightness up but you still haven't overloaded any of the cables or fuses then this is okay.