2

Im working on a project with LED light strips, and want to connect them all to a sd controller. The lights are ws2812b 60 LED/meter, and have 20 meters of it. It calls for 14.4w per meter @ 3 amps per meter. Can I hook all these strips to one power supply of 400W 80A?

2

The power rating of the supply must be higher than the power rating of the load -- so based on the numbers, yes, this seems sensible.

However, the strip lights themselves will not support running that much current through them -- which means you can't just daisy-chain all the strips lights.

From https://www.pololu.com/product/2547:

  • The 60 LED 1 m strip drew 3.0 A and had a voltage drop of 0.6 V.
  • The 120 LED 2 m strip drew 4.7 A and had a voltage drop of 1.4 V.

The voltage drop means you'll have dimmer LEDs.. and at some point they'll stop working entirely. To get around this, you should provide power to each strip. You can interconnect the data lines, but separate power wires should be run to each segment. How long the segments are really depends on how much voltage drop you can tolerate (how dim the LEDs at the end get).

enter image description here

You can use a voltage drop calculator (Google it) to figure out the size of wire you should use for the distance and power draw -- but expect to probably run 18 or 16awg wire from your power supply to the segment.

It may also make sense to use multiple smaller power supplies (with shorter runs), depending on your distances, room layout, etc.

  • So if i want to run a sequence to all the lights do i daisy chain the data wire and send power to the strips say every 10 meters from the same power source on separate wires ? – damian Jan 6 '15 at 2:37
  • Sorry, I wrote that for 5050-style LEDs, not individually addressable with a data bus. Updated -- and yes, you can daisy chain data wire and have separate power. – gregmac Jan 6 '15 at 3:17
  • Separate power? or can i run separate wires from the same power source which has multiple connecting out ports to the led strip every 10 meters? – damian Jan 6 '15 at 4:36
  • Either works. It really just depends on the exact situation: you just have to balance the size/length/complexity of wiring, cost of power supplies, and availability of space. – gregmac Jan 6 '15 at 4:41
0

I've done a few projects like this. My guess is that 10 meters is probably too far apart to get results, though it depends on the copper thickness on the strip that you have. I'd hook them all together in a strip and then just add in the +5V and gnd connections every 5 meters; this powers the strips from both ends. You might get away with 10 meters if you do this.

You are going to need some hefty wire to deal with the voltage drop as you are pushing a lot of power through it. A quick calculation says that 5 meters of the strip takes 15 amps of power. You can find some wire resistance calculators online that will help you with this, but my ballpark guess is that you will need 10 gauge wire if you power at both ends.

IIRC, the ws2812 is constant current so voltage drop might not be that bad, but you'll want to experiment.

Finally, make sure your controller can handle 1200 LEDs. That's a lot to drive and you may see very slow update rates. Many projects break them up into multiple smaller strips.

  • My plan is to cut the strips in to 1 meter lenghts to make a 20 row x 1meter panel and run power to the first row and then to the 10th row i figured that using a 400w 80a power supply should be enough to power the lights – damian Jan 6 '15 at 10:43

Not the answer you're looking for? Browse other questions tagged or ask your own question.