I am using 4 WS2812B strips of 300 LEDs for 1200 LEDs total. I'm having issues with power. I have the data line wired from each strip to the next sequentially.
Powering all the strips from a single power supply gives me the results I want, and all lights work in the correct sequence. But a 75W power supply heats up quickly, even with brightness limited to 120. A 300W power supply would handle the maximum load, but it has a fan that is very loud in a quiet room. I can't find anything bigger than 150W without a fan.
Powering each 300 LED strip with it's own 15W 5V 3A power supply gives me inconsistent patterns on each strip. Only the first 300 do what the code is telling them to do. The other strips give distorted results.
Before I spring for a 150W fanless power supply I would like to understand what others are doing in similar circumstances. Is there something I need to do to regulate the power from different supplies?
There are a number of rules to be considered here.
The power (which is 5 V and ground) should connect in to each strip every 50 LEDs (2.75 A) from a reasonably heavy cable and that of course includes both ends of the strip. 5 V and ground should always be reticulated as a pair in some form of twin cable. Possibly the same sort of stuff used to wire your house (2 mm2), although this has unnecessarily thick insulation for just 5 V.
Where the data transfers from one strip to another it should go without saying that the data and ground travel again as a twin cable. If the separate strip sections are powered by separate power supplies, this ground is the only necessary connection between the grounds of the different power supplies, however if the power supply grounds are connected together elsewhere, then the ground connection that goes with the data must have the same rating as the power cable.
It is advised to have a 330 or 470 Ohm resistor in series with the data input at the start of each separate strip section and a 470 µF or more capacitor between 5 V and ground at that same point.
Thanks, but I am confused by what seems mutually exclusive:
“5 V and ground should always be reticulated as a pair in some form of twin cable”
and:
“the data and ground travel again as a twin cable”
Are you saying the the ground is common between the strips, even if each strip has a separate power supply? I.e., the data and ground are connected sequentially strip-to-strip, and the red + are wired separately to individual power supplies?
All connections between parts of a system must consist of a supply and a return - or data and return - and the two must travel closely together to avoid coupling of interference between one part and another.
So you connect each strip directly to its corresponding supply by a twin cable - 5 V and ground. You also connect the end of one strip to the beginning of another using a twin cable - data and ground. If the grounds of the different power supplies are not connected together that does not matter as long as the ground is connected from one to another together with the data.
If however the grounds of the different power supplies are connected together in some other fashion, it is necessary to ensure that the ground of the data cable can carry any return current from the LED strips that may use this alternate path back to its own power supply via without resulting in a voltage drop along the data ground that may interfere with the data.
That's it. Thank you so much. It works great with separate power supplies for each strip, and the ground tied together between strips. I was missing the strip-to-strip ground connection.