I am new to this however I am looking to switch from my GE color effects to permanently mounting some WS2811 on the house. I have been researching and think I have it figured out however want confirmation I am understanding the power correctly so I don't burn down my house in the process.

I would like to install a single power supply in the garage to power the 500 - 12V WS2811 lights. The main level is fine however the second level is where I need confirmation. I will have about 250 lights on each level. So 5 strings @ 3amps each for the second level is 15 Amp @ 12V. Now to supply this power over a 75 foot run using the online calculators I would need about a 2 Awg gauge cable to avoid to much voltage drop which I don't want to run. Reading the forums it sounds like I can simply just purchase a 48 Volt 10 Amp Power supply. Using the online calculator I could use a 18 AWG cable to deliver 5 AMPS @ 48V and the drop at the end would be 43V. I would then use something like this from Amazon to step down to 12V @ 20 Amps which would be enough to power all 5 strands of lights.


I would do the same for the bottom with a step down transformer however the run is a lot shorter but would like to also use the 48v PSU.

Will this work and am I understanding correctly that stepping down the volts proportionally increases amps. So a 48V - 10 AMP PSU will supply the equivalent of 12V - 40 Amps which would be enough for a controller and the 30Amps worth of lights. Am I correct in my research that the second level will work fine in this setup? The wire gauge is fine and is within spec as I see it can carry up to 7 Amps over 50ft runs? Is there anything I am missing or does it all look correct?

Thanks for your help.