110 feet of SK6812

Hi… Total noob to WLED, but I have dabbled in BASIC home automation as well as BASIC led lighting.

I had a scenario that i could use help planning out:

90% of our house has straight white 3500k led accent lighting everywhere (cabinets, counters, toe-kicks, etc). Trying to keep it clean and minimal.

The living room has a large tray ceiling (20’ x 35’) that I want to light white most of the time, but every now and then go with designs or colors based on parties, holidays, etc etc. The ceiling looks kinda like this

For this reason, I’m leaning towards 5v SK6812. I’ve got 4 outlets at each corner in the tray ceiling, so power injection and running wires isn’t a problem.

From my research, I think I will need:

  • a 20A power supply for each 20’ run, and a 40A power supply for the 35’ runs, with power injected at either end and along the middle of the 35’ run?
  • TWO esp32’s…? it looks like I have about 2000 LED’s total

My questions (few of many):

  • is my equipment list valid? assuming I put a power supply at each corner, and an ESP32 at two opposite corners?
  • Can i control 55’ of SK6812 with one ESP32? 60LED/m = 60*18 = 1080 LED’s
  • I’m assuming I can use the WLED app to synchronize my two ESP32’s to create one large light array

I have a feeling I’m looking at this wrong, but I don’t really know which path to even start on :slight_smile:


My general rule of thumb for LEDs is to assume a max of 0.3W/LED and do my power guess calculations from there. In general what you’ve described sounds reasonable power wise. The power injection details may require a little more thought depending on the actual LEDs you finally decide to install.

Again, in general you would try to position your injection points towards the middle(s) of strip sections so that 1 injection wire supplies power to 2 strip sections. You then further divide your strip into 1/4’s or 1/6’s or 1/8’s giving you 2,3,or 4 injection points respectively. You decide on how many points based on how your strip reacts at full White brightness (the “worst case” power draw).

The easiest way to find out for real is to bench test 100 (or even 200) LED’s at max brightness and measure both the total current draw and the voltage drop along the strip after a simple injection on one end. At some distance from the injection you’ll measure an “unacceptable” drop, usually more than 10% of the original - 4.5V for a 5V supply. That distance is how far the strip can supply power without another injection point. Multiply that distance x2 and divide your strip into that many sections, each one will need an injection point in the middle.

You may need to increase the number of injection points to allow for the length of the injection lines from the power supply. The total current draw you measured earlier will tell you how much current you’ll try and supply through the wires of each injection point. Depending on the wire size you choose, you’ll have to account for that additional drop as well.

As far as the total number of LEDs you can drive from an ESP32, 2000 is not unreasonable. If you’re simply looking at static lighting with some dimming, a single GPIO pin will be no issue. If you want to run colour effects, you can subdivide the setup across multiple GPIOs to keep the strips under 800 LED’s per pin to get max FPS. You likely will have good results even at 1080 LED’s on a single GPIO.

The sync function will make it easy to treat the entire setup as a single strip if you go with two although that’s not necessary from what you describe.

This is spectacular info and I’m up and running!

Here’s what I got going so far:

  • ESP32 running WLED
  • 5v 40A power supply
  • TWO 5m SK6812 strips (60 led/m) for a total of 600 LED’s
  • one data wire running into the first strip and then continuing (no level shifter, but the distance from my ESP to the first data injection is like 10"
  • power into the beginning of the first strip and the 2nd (though I might want to add power to the end of both as well)

Here’s my next Q: do I really need a level shifter if my initial data link is so short? I assume after the first LED, the data signal gets to 5v anyway right?

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Personally, I’ve had good success without level shifters for short data runs (<50cm).
The proof is typically in the first few LEDs, what you’ve described sounds like a good setup so far.
If it does prove problematic, it’s not really difficult to add a level shifter inline with your data.

Power is almost always a bigger issue than data, think seriously about how you can power inject in the middle of the 1st and the middle of the 2nd strip. You don’t need to worry about the ends at all. If you do bench tests and measure the voltage drops at max brightness, you’ll find that setup will give the most even spread of power.

how exactly did you connect the Power supply?
cause i’m about to recreate your exact same setup