Has anyone got some good rules of thumb to follow?

Hi,

This is will be my first attempt at setting up a light show this year and I am reaching out to see if anyone has some good links or tips for doing the calculations prior to ordering and install. Apologies if this is a long read but I appreciate any help.

My current plan is:

Roofline:

18m 12V WS2811 30 LED/m strip

540 LEDs

180 controlled zones

Arches:

4 x 2.5m 12V WS2811 30 LED/m strip

300 LED’s

100 controlled zones

Pixel Props:

5 x 100 WS2811 12V resistor pixels.

500 LEDs

500 controlled zones


As for the arches I am tossing up between 30 and 60 LED per meter. I have read 30 is fine in 32mm airseeder tubing and I like the idea that the roofline and arches are the same strip to have better spares available. But I am considering using 60 led/m for the arches for added definition (this may be lost in the dispersion of the tubing though…) as the arches will be a main feature of my display.

Proposed layout:


Planned Controller:

I am planning on using a raspberry Pi 4B 4gb which I already have and running FPP and using a Hanson Electronics RPI-28D+ cap. This will give me 2 controller outputs for the WS2811 with the option for 4 with the FPP license key. I would plan to run 1 port for the roofline and then 1 port for the props and arches totaling 2 controller output ports for the show. As for the lawn props I plan to link them all together which would mean I only need to do a big control cable run to the first prop with the other runs only being between props that are next to each other.

Power Supplies:

For power supplies I am planning to go with the Aliexpress versions of the meanwells initially for the 12V supplies. I can have power sources on the left side of the house and in the carport on the right. Ideally I would like the controller to live on the right side under the carport and run cables out from there. I would be interested to know if these cable runs will be too long in practicality and the controller needs to be moved to get the signal closer to the props. I feel I can mitigate any of these issues with a booster like a false pixel mid way if required. There may be an impact of voltage drop over the power wires but I am happy to size up the copper within reason.

Now for the bit about calculations. How much power will I need and how many PSU’s.

I have read that 12V WS2811 resistor pixels consume about 0.72 Watts on 100% and white and that 12V WS2811 30 LED/m strips consume about 9W per meter.

Roofline = 18 * 9 =162W

Arches = 10 * 9 = 90W

Props = 500 * 0.72 = 360W

Total = 612W (I feel this is too high and in reality would be less?)

So I plan to power the roofline from both ends to mitigate any colour loss from voltage drop. I know we need both psu’s to be connected by ground but I read that we can’t have the lives connected unless we spec for expensive PSU’s built for this. Does this mean halfway through the strip I need to break the positive connection on the strip to keep the two PSU’s power source independent on the live line?




Also noting that I won’t be running the display on 100% brightness, I read something in the range of 30 – 50% is more appropriate but I assume the power usage it not linear and it would not be half the number of watts?

Ideally I want to run everything from the right side of the house for power (expect the left side of the roofline strip) as this is more convenient. But I am not opposed to running power to the left side of the arches from the left of the house.

How many wires can I run out of my PSU, as many as there are terminals available for? In terms of wattage is it a case of as long as its under 80% of the PSU’s watt capacity it is all good (given a aliexpress PSU… I only want to use 80% of what it is ‘rated’ at).

What do people think, Would I be okay with 2 12V 350W PSU’s one on the left and one on the right? Or would I need 3 with 2 being used to power from the right side?

I am starting to think now that I should have 2 PSU’s the left powering half the roofline and the arches, and the right powering half the roofline and the props but the right might need to be more than 350W to comfortably power everything.

Now for running the power cables and the power injection. With 16 AWG wire at 12V over approx. 5 meters I’m hoping that this would be sufficient. If anyone has some good rules of thumb for this on how much voltage drop you can get away with for 12V ws2811 I would love to know.

Also regarding fuses, the inputs to the LED’s will be protected initially by the fuses on the Pi cap. I also want to use fuses on the input power to the Pi cap from the PSU and fuses on all power injection lines coming out from the PSU’s to the middle of the LED runs. Is there a good way to determine what fuse rating to use?

Enclosures:

How do people deal with heat dissipation in waterproof PSU enclosures. The 350W PSU’s come with a fan but how do we get airflow through the sealed box, are there some fancy air vents people use or does a roomy waterproof box have enough air to keep things safe? Does anyone have some good rules of thumb on boxes to use for controllers and PSU’s?


In short if anyone has some good links or rules of thumb to help calculate the number of PSU’s required prior to purchasing and install that would be great. Also any theory on how to correctly do fuses and the sizing of wires would be great to know! Any tips in general would also be very welcome! I am looking forward to playing around with lights this year.

Thanks for reading

Rather than using a Pi, rpi-28D+ and a 12V power supply with a fan I would suggest going with the new Baldrick controller that I currently have on the way from UK and the 12V 500W waterproof supplies that I have. The Baldrick controller has 8 outputs versus 2/4 and by using the waterproof power supply you can bolts it to the outside of a box and there is no need to have a fan or vent in the box.
For your first year and for the ease of setting up I'd suggest just breaking the props in half (2 pairs of arches, 2 9m runs on fascia etc) and running each from an output of the controller and not have to worry too much about any sort of power injection. If you use 3 core mains flex of 0.75mm2 or preferably 1.0mm2 you should have no issues running pretty much everything up towards 100% brightness.
The 500W supply has 2 outputs for it's 42A capacity. With 1 output to each of the Baldrick controllers 2 inputs you can come close to using the full capacity of the board.
1 Baldrick controller (they are due somewhere around 7th June)
1 12V 500W power supply
8 40cm female pigtails
2 4 hole cable glands
1 box. The box can be small as Baldrick is diminutive and with the power supply on the outside of the box you don't need that room inside.

I am too lazy to work out all the wattages but I would be quite surprised if it was close to 500W at 100% brightness. Resistor 12V pixels are somewhere around 0.36W.

Matt430 said:

I have read that 12V WS2811 resistor pixels consume about 0.72 Watts on 100% and white

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They absolutely do not use that much (even though I have vendor tags from at least 2 vendors that say they do). The max they can possibly use is half that, and as the voltage drops they'll use a bit less. There are some options like GS that use significantly less watts for the same light.

As for the arches I am tossing up between 30 and 60 LED per meter.

Click to expand...

IMO those will both be fine. I have 2m arches with the 30 segments/meter strip, you can notice that they're pixely if you think hard about it. Since yours are 2.5 they'll be a little better.

The two things I would consider if I were you:
1. The distance between your props and the power. You may find yourself needing data amps at 9m distances... I think with my little arches I have a 50/50 chance of needing an amp at 8-9m away with the standard xConnect extensions they sell, and yours would be an extra half meter. Similarly with your roofline, you may do well to run a power wire behind it (some of the strip channel has plenty of room for this) to get voltage to the middle.
2. Future expandability. If you might add props in the future, you may find that you're putting power closer to the props. That means more PSUs but also less cable, and also suggests a controller with long range ports on it (or a 2nd controller eventually).

With the LED strips, (Iv had LED gutter line in my show for last few years)

They are pretty fragile, and mounting to pvc pipe or something will help, (zip tied)

They typically come in 5 meter rolls, so butting lines up close together can be a challange,

Waterproofing, the silicon cover is ok, but smallest hole and water can get in, so keep an eye on it, and look for any clouding,
Once water get in, strip rusts quick,

If a pixel dies mid strip, it can be a pain, you would need to remove the silicon cover off the strip enough to repair and then refeed it back in, can be done but not a fun job,

I love the look of strip, and will be replacing my gutter lines as i had part die last year,
Strips are good on things that are regid.

But can be tricky,

There is a saying in the hobby, friends dont let friends use strip,

The waterproof PSU's is an interesting idea, definitely something I might look into. I plan to keep the gutter LED strip up year round so using a waterproof PSU on the side of the house might be a good idea and this was the reason why I wanted to use a strip vs pixels for the roofline as it will be up year round and want it to be minimalistic. I currently have some non addressable strip on the gutter from last year and it has held on fairly well.

My plan for the first year was to start out my learning journey with the Pi as I already have this and that way next year I will know which controller will suit me when buying another .

Good to hear that the 12V pixels do not use as much power as advertised and I think using some decent cable would get me out of any trouble of running wires out from the controller. But I may need to splice in a data amp mid way on the long runs which I am not too afraid to do with a little junction box.

I also like the idea of having nodes around the place with power and long range controller ports using ethernet cables from the main controller. Definitely something to consider as the show will inevitably grow .

In regards to the strip I have seen IP65, IP67 and IP68. I like the idea of the IP65 and IP68 strips being a full resin like cover but I am not really a fan of the tubing of the IP67 as I feel any scratches would ruin the tubing's integrity fairly quickly. I can find lots of sources of IP65 strip but IP68 strip is much harder to find. The only places I have seen so far have crazy shipping costs per roll. Does anyone have a good source for getting 20m or so of IP68 strip?

Thanks for the tips I appreciate it

Matt430 said:

I like the idea of the IP65 and IP68 strips being a full resin like cover but I am not really a fan of the tubing of the IP67

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IMO from my usage, the tubing is loads better. It's much easier to work with and repair. You don't have to worry about the intricacies of scraping the resin off to make a solder joint and then re-coating it...... Also the resin strip I had was only front coated, so no protection in the rear.