I am designing a new project and i am at the point of choosing my power supply if i am going to drive 240 leds with the maximum possible brightness and use the fastled hsv(x, 255, 255) function.
Would it be acceptable to calculate 240 * 0.03A = 7.2 A for my power supply?
I always end up buying bigger power supplys than i need which cost way more money.
I believe that’s 60mA each and not 30. You also might want to read up on FastLED power management and artificially limit the amount of current available.
60mA would be full white iirc
Most of the 5050 RGB LEDs can draw up to 60 mA each so 240*0.06A =14.4 amps. I generally don’t run power supplies at more than 80% load so 14.4/0.8=18 Amps. Get yourself a 20 Amp supply 
But be careful runnning LEDs at full brightness for too long…
Sorry, the LEDs can draw up to 20mA per channel. So reduce by 1/3 as you’re only using two channels
@Jeremy_Spencer . He is using hsv (x,255,255) so any color at full saturation and full brightness. So you can get the maximum draw of 60 mA for each pixel.
Each color takes 0.02A and AFAIK the hsv at full brightness never goes beyond one led at full brightess
I’m pretty sure that white at full brightness is the same whether you call it via HSV or RGB. So if you want to be able to safely power 240 LEDs at full white brightness then you should use a 20 amp power supply.
I’ve got 250 on my deck which I use a 20 amp supply for…
So if i need to drive 820 i would need a 50A power supply?
Or would it be better to split the power between 3 sections and supply 10A to each section?
That’s a good point about a CHSV(x,255,255) not requiring all 3 LED’s, however I’m not sure why you would want to limit yourself to CHSV(x,255,255) anyways. The use of palettes abstracts the colours from your underlying algorithm, and provides a LOT more flexibility with your display sequences. Again, if I want to limit current, I’d be using the FastLED power management function.
@Cristian_Martinez It’s okay to split the power supplies as long as you tie the grounds together.
One might be more convenient… three might be cheaper.
Now since we’re on the subject can 820 LEDs be run as a single strand? Or do i have to have more than 1 data line?
@Cristian_Martinez , APA102s or SK9822s? Or something else?
With ws2812b you would definitely get a bad framerate.
I was thinking WS2812Bs since its the only RGBs ive ever worked with. But what would you guys recommend?
Jeremy Spencer already mentioned APA102.
For 820 I’d be tempted to use SK9822s. They’re very similar to the APA102s but much much faster. I’m sure that I read on here about someone who had less problems with them in very long strips too. I think that the IC reshapes the clock signal as well as the data signal but I’m not 100% sure.
I’ve not tried a very long strip of them yet, but i will soon. I buy my strips in kit form, so it’s not as easy as just clipping them together…
Where do you buy them from?
Ray Wu on AliExpress. I’ve got 2500 being delivered this week