PiPixel input power max

Hello, I’m working out the details of adding LED strips below a bar, and I have a few questions regarding your PiPixel board (https://www.tindie.com/products/ManiacalLabs/pipixel-raspberry-pi-led-strip-hat). I’d love to reduce the “rats nest of wires”. :slight_smile:

I noticed that the Usage Guide says:

The PiPixel has two input options… For both the maximum current is 5A. If you need more power, you will need to splice power into the LED strip further down the line.

I’m going to be using a 5V 30A power supply for this project, and I plan to power the Raspberry Pi with a separate (smaller) power supply. If I understand the above statement correctly, plugging the power supply directly into the PiPixel will fry the board.

I’ve attached examples of what I’m trying to achieve. Both options have the power running through the board (which I will adjust as necessary). The second option is a tentative plan to address any potential voltage drop if it happens.

Two questions:

  1. Is the above assumption correct? Will my plan, as diagrammed, fry the board?

  2. If so, do you have any diagrams or corrections you can provide on how to bypass the board safely?

  3. Lastly, even if rerouted the input power (answer to #2), do I need to worry about the ground coming back to the PiPixel? In other words, if there was a surge or overload of some sort, would the additional amperage flow back and fry the board from the other direction?

A 30A PSU will not fry the PiPixel unless you try to draw 30A through the PiPixel. Remember, voltage is pushed, current is drawn :slight_smile:
Since you have a separate power input on the LED strips you are fine.
But you don’t actually need to power the PiPixel separately at all. The power input on the board is JUST for the LEDs, otherwise it’ll get the 5V it needs for the level shifter chip from the Pi itself.
And you MUST have a common ground between the PiPixel and your LED power. As long as you connect the LED strip ground to the PiPixel ground you are fine. No current will flow back through that - unless you wire it COMPLETELY wrong :wink:

Thanks for the super quick response!

Since you have a separate power input on the LED strips you are fine.

Are you referring to the dotted red line within the diagram? If so, should that line be moved to connect between the PSU and the PiPixel? In its current position, the draw would still flow through the PiPixel and fry it, correct?

But you don’t actually need to power the PiPixel separately at all. The power input on the board is JUST for the LEDs, otherwise it’ll get the 5V it needs for the level shifter chip from the Pi itself.

Oh! I think I understand what you’re saying. So, the power being pulled from the Pi to the PiPixel is simply for the data line? If that’s the case, I can remove the two lines (red and black) between the PSU and the PiPixel?

And you MUST have a common ground between the PiPixel and your LED power. As long as you connect the LED strip ground to the PiPixel ground you are fine.

I do have that now (green line), but I think I may need to make some additional modifications depending on any follow-up answers you provide.

Oh - right, yeah, just remove the PiPixel from that part - go from the PSU straight to the LED strips

Yup

Great! I think I’m getting it now.

Changes:

  1. Running power directly from the PSU to the LED strips in two places (to avoid voltage drop)
  2. NOT running power directly into the PiPixel
  3. NOT running power from the PiPixel to the first LED strip
  4. Running the negative wire from the PSU into the ground wire between the PiPixel and first LED strip
  5. NOT running the negative wire directly into the PiPixel

Does this look accurate now?

Also, for #1, do I need to run a negative wire (black dashed line) anytime I inject power in between strips? (i.e. red and black in tandem every time)

Hi, @adammhaile. Any thoughts on the questions above? I’m eager to make some purchases. :slight_smile:

Might as well still hook up ground. It won’t hurt.

Yes - always leave ground connected. Even if using multiple power supplies.

Thank you for all the advice. Much appreciated!

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