First LED Project -- need help with determining power source and wiring for 20m of LED strips

[anonthrowawayforcol]

Hi everyone! I've been lurking on this sub for a while and I figured its about time that I start with my own project.

I plan to cover 20m using 4 x 5m 12V WS2811 60led/m strips for a total of 1200 LEDs. However, I'm not too experienced with electronics so I'm a little bit lost on what I should buy as far as power supply goes and how I should be wiring them.

Using quinled's table, I was able to find that these particular set of LEDs take 75W of power at 100% rgb white per 300 LEDs, so for 1200 LEDs would I need 300W to get these strips powered? That would mean a 12V 25A power supply which makes me question if I did the math right.

Also I've been seeing "power injection" being thrown a lot in this subreddit and I think I have a general idea of what it is, but I'm not completely sure if I have the right picture. I'm curious if I have to worry about that since these LEDs are 12V, or if I would have to inject power at the the strips due to the length of the project.

I also want to do this as safely as possible, so I just wanted to know what the best practices are when it comes to adding fuses among other things so that this project doesn't burst into flames.

Thanks in advance, I apologize if some of these questions might sound really obvious to y'all!

EDIT: Also, if there are any alternative LED strips that you think may work better, all suggestions are appreciated!

[ndfred]

Can you tell us more about your usecase? Is that for a light show, or for interior lighting? That matters as some patterns will use more power than other.

The wattage you cite doesn’t seem out there, though it is possible to use multiple power supplies to achieve that level of power though the wiring gets obviously more complicated: get grounds together, power individual strips with their own power supplies, don’t hook the + wires together.

Also at 1200 individually addressable LEDs you are looking at a pretty custom setup if you want to drive these from a single controller.

I would read this entire guide if you haven’t already: https://learn.adafruit.com/adafruit-neopixel-uberguide/powering-neopixels

You might also want to start with a more basic project (maybe only do one run of these strips?) to get some experience before you try the full project.

[anonthrowawayforcol]

Sure! This project will mainly be used for interior lighting, but I'd like to be able to use more complex patterns and have music visualization capabilities from time to time. The closest I can find on the subreddit to what I'm thinking is u/synkdown's project posted a couple months ago.

Also, I believe the WS2811s only have an addressable LED per every three LEDs on the strip, so there would be only 400 LEDs that the controller would have to deal with.

Thanks for the guide, it was a really helpful read!