LED Power Supply/Amperage

Came across this diagram as I am designing a lighting layout with a ton of NeoPixel LEDs:

I will have approximately 165 Adafruit NeoPixels in the setup, totaling an amperage need of around 9 amps for just these LED pixels in the strip. In addition, I will need to wire around 10 additional simple LEDs to another output pin and will have the Adafruit Music Maker MP3 shield connected.

I’ve estimated that I’ll need around 15 amps to properly power it all. I’m at the point where 1 5V 10A supply is too small, but 2 x 5V 10A to spread out the amperage would be a bit overkill. This leads me to my main question: Is a single 5V 15A DC converter the best way to accomplish this? If so, I’m assuming the wires will have to be a tad bit bigger than the breadboard jumpers I’m used to lol

Yes, 9 Amps.

An output pin can only provide up to 30 mA, however many LEDs you connect, unless you intend to use a transistor to switch them.

A number of points. You need a power cable - at least 1 mm2, preferably 2 - to run alongside the LED strip to tap into 5 V and ground on the strip at least every 50 LEDs and each end. The ribbon will not properly carry 9 Amps.

The 1 mF capacitor and resistor should be at the very start of the strip.

All wiring needs to be paired - 5 V power running as a pair with ground and data running as a pair with ground. This means you connect the power to the start of the strip and then run your 5 V back to the Arduino together with the data line and ground.

Hardly anyone uses mF anymore, as it was sometimes ambiguously used to mean either micro or milli Farads and created confusion. That is why it was echoed back to you as 1 mF. In fact the correct value is probably 1mF or 1,000 uF. Just to save you the smirks at the parts store... a 1,000 mF cap is a 1.0F cap!

Which demonstrates how far you can trust some colourful diagrams that float around the internet.

Don't forget to feed the power from both ends of the strip.

Actually, the older convention was "mFd".

I (always) put it in to be provocative. "mF" is the actual SI correct unit for milliFarad. :grinning:

Thanks for the input! Yeah, I was wondering about the 1000 mF lol I also figured it was probably meant to be 1000 uF.

I'm looking at 16 gauge (1.27 mm sq.) wire for the main power supply. Do the jumper/connector wires from the main power cable to the individual light strip connections and Arduino 5V pin have to be as thick? I would assume not, since the power is branching out, but just wanted to check. Same goes for the ground wires and data wire.

Again, thanks for the input!

That sounds about right. :grinning:

Now as the cross-connects are short, their gauge is not critical, it makes sense to have them of similar gauge as the LED strip itself.

Just had an epiphany: the light strip I'm going to use is made up of Mini NeoPixels. That means that the amperage needs are far less than regular NeoPixel LEDs. From the AdaFruit website: "These LED's use about 9.5 Watts max (~2 Amps @ 5V) per meter." That means that the absolute max amperage needed for my setup would be 5.83 A. So the actual amp usage is likely to be around 3 A or so.

I can't believe that I missed that lol This means I could probably get away with a 5V 10A power supply and smaller gauge (18?) main power wire.