Power supply to pixels comparison?

[ChristmasPolice]

First and foremost, I'd like to thank you all as this forum has been an incredible resource for me as I start this hobby. I've been getting a bit confused in terms of the amount of power supplies I'll need. For instance, I've read sellers advertising a max power of 0.6w. For a 350w power supply I understand this would be able to power roughly 583 pixels. However, in terms of using different brightness how do I do this math as pixels running at 10-20% power would not be using 0.6W? I'm sorry if this has been asked before.

[rstehle]

Hi and welcome!  I guess the first thing to mention is that the .06w is all on at full white.  Most enthusiasts don't have all of their pixels on at full white often.  So, since each Pixel has 3 led's, draw would be .02 with one color on at a time, which greatly increases the number of pixels you can run. (note here - you want to leave a safety factor, so most folks plan to only use 80% of ther total power available) If you plan to run at lets say 50% brightness (for ease of math), then you power usage is reduced by 50%, meaning that you could run twice as many pixels.  The ratios hold true at whatever brightness level you choose.  With normal sequencing using xlights or Vixen effects, I would imagine that you could run WAY more than 583 pixels on one PS.  I'm sure others will chime in to give you real world experiences.

[k6ccc]

First of all, a correction.  The most commonly used pixel type (WS2811) draws about 0.060 AMPS (not watts) at full white.  That does not matter if it is a 5V or a 12V pixel.  Therefore, when running 5 volt pixels, the power is about 0.3 watts per pixel and at 12 volts it is about 0.7 watts per pixel.  That DOES VARY between different batches and manufacturers of pixels so you really need to measure the pixels you are using.  Rough numbers (allowing for some power supply overhead - not good to plan on running at 100% load on the PS) is a little over 400 pixels for a 350 watt power supply at 12 volts and about 1,000 pixels for a 350 watt power supply at 5 volts.  Both those numbers would use about 85% of capacity of a 350 watt power supply with all pixels at 100%.

As for how much it changes if you run lower percentages, that also varies, but check out post #13 in this thread:
http://falconchristmas.com/forum/index.php/topic,12633.0.html
I measured four different sets of pixels at everything from 0 to 100% and documented it, and then posted it in that thread.

As to how bright you will run your pixels, it depends a lot on pixel density and the application.  For example, my pixel tree has 2,400 pixels in a tree that has a lit portion of about 11 feet.  By comparison, on my roofline, I have one GE Color Effects bulb every 10 inches.  I run the roofline at 100%, but not the tree (most of the time).  There are a couple places where I do momentarily have the tree all full white, but it is really bright POW in your face intent that only lasts for a very short period.

[anthmillward@gmail.com]

Check out this tool. It is very helpful in determining power consumption and demand. The site was built for this exact reason.  Cudos to Spiker Lights. 
http://spikerlights.com/calcpower.aspx

[ChristmasPolice]

Thank you all very much! This information is super helpful and informative.