I’m looking to install ceiling LED strips in a small guest room to see how it looks and runs before attempting anything in a larger space.
For the whole ceiling I’ll need just under 12m of LEDs. Assuming I can find a deal I’m going to get 144/m strips of WS2815s. Theoretical power requirements would be around 100A so I would probably buy a 12v 75A-80A PSU because I don’t care about 100% RGB white.
Since there will be around 1700 LEDs I was going to use an ESP32 with 512 lights per pin. Does that mean I would need to combine the lights into 3 3.5m strips and a smaller 1-2m strip each with their own data line? If I do it right, the longest data line would be 7-10m depending on where I place the ESP32 and the PSU. Would AWG 22 wire work for that?
I’ve read a lot about 5v power injection and that you should do it every 150-300 LEDs. Is there a similar rule of thumb for 12v? Which gauge of wire would work best?
Would I be able to power the ESP32 from the PSU using a step converter or would it make more sense for the board to be powered separately?
The last thing I’m curious about is fuses. I’ve never done an electrical project this complicated before so I’d like some safeguards in place. What kind of inline fuses would you recommend?
After a bit more research I’ve come up with some answers.
If I do it right, the longest data line would be 7-10m depending on where I place the ESP32 and the PSU. Would AWG 22 wire work for that?
10m is pushing the limit for the data line but should be ok. I won’t know if AWG 22 will work until I get everything put together.
Would I be able to power the ESP32 from the PSU using a step converter or would it make more sense for the board to be powered separately?
Had I read the wiring diagram a little closer then I would have known that a 12v to 5v step down converter is needed. Getting Started - WLED Project
I’ve read a lot about 5v power injection and that you should do it every 150-300 LEDs. Is there a similar rule of thumb for 12v? Which gauge of wire would work best?
I still haven’t found out much about this but it seems that inject as needed is the general rule. 12V LEDs don’t have the same power loss problems as 5v, I’ll just have to see how it works when everything gets here.
The last thing I’m curious about is fuses.
I’m still al little fuzzy on this one but I think I need to use a 1A fuse between the PSU and the eps32 and a 80A-100A fuse between the PSU and the LEDs and the PSU and any injection points.
You’re on the right track with most of this, congrats on wading through the info.
Possible issues:
10m is long for a data line IMHO.
22AWG should be fine as there is little to no current for the data signal.
Look up “Long Data Lines” in the KB for some remedies.
Power injection is based on the amount of voltage drop seen across a string of LEDs.
I do my calcs based on the worst case scenario of 100% White for all LEDs in the strip.
My experience is that 5V LEDs can go 50-75 pixels before significant drops, while 12V get about twice that.
If you inject at the “middle points” of your strip, each injection line can supply 100-150 5V LEDs (up to 75 on each side of the injection point), but the actual wire needs to supply twice the current of 75 LEDs.
The size of the wire depends on the current it needs to carry and its length. Figure out how much injection current is needed for each wire, how long it needs to be and plug those numbers into a Voltage drop calculator. You pick the wire size to keep the voltage drop of the injection line down to acceptable amounts.
Fuses are to protect the injection wires. Hopefully you don’t have any single wire that will need to carry 80A! You spread that out over the injection wires which each carry a much smaller load and you fuse for that smaller load.
Note that 12V LEDs reduce much of this current by a factor of 2 (at least) and make things easier to handle all around.
Fuses are to protect the injection wires. Hopefully you don’t have any single wire that will need to carry 80A! You spread that out over the injection wires which each carry a much smaller load and you fuse for that smaller load.
That makes a lot of sense.
One more question about wiring injection points. If my PSU has 3 12v outputs but I need 4 injection points can I double up wires on the same output?
That’s what the multiples points on the PSU are for.
To look at it another way, if the PSU can supply 80A, those three terminals are like a short piece of heavy wire designed to handle 80A total on all of them.