Hi,
I want to power 8-10m WS2812b RGB Led Stripes (see Adafruit Neopixel 60 leds/m).
(I will start at 8m and maybe extend to nearly 12m.)
These are 5V LEDs, most of the LED drivers are 12V. I want full closed (waterproof) PSU.
But only some open frame versions have 100W at 5V. Most are 12V or higher.
Is it better to use 2 x 40W at 5V to power the LEDs from both ends (cut ‘+’ in the middle).
Or should I use 12V 100W and transform it down to 2 x 5.xV at a high ampere level?
@FloX, Personally i prefer to reduce the power wastage from conversion.
Unless you are talking about high efficiency step down buck converter from 12V to 5V… Or i’ll just go for the 5V PSUs
Why would you want to split the LED strip into 2 and power them separately?
That’s a good consideration if you want redundancy should one side fail you still have the other running. Or maybe the idea of having 80W on a single pair of wire sounds beefy? 
I’m just wondering about data transmission since WS2812 is chained and the individual LED data is one after another and the timing might go off towards the end. Just a thought but i have seen people running 100s-1000s of WS2812!
I previously bought a 1 x 8 from RGB123. You might want to look at this:
I read that when powering the strips on several points, you have to combine all GND but split the ‘+’ so each segment will have its own power supply. The reason of doing this is to eliminate interference between the PSUs.
I’m looking for something like that http://www.meanwell.com/product/led/LED.html HLG series.
So fully closed, no air flow inside. It seems only the 12V psu are closed. All 5V that i have seen looking like the one you posted.