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I understand that the Zero W USB port has just the power lines connected to all the power on the board (+5V and GND). I also understand that you can use something like Adafruit PowerBoost 1000C to power by connecting to those rails (e.g. using PP1 for +5V and PP6 for GND).

In that case, the PowerBoost would have a lipo battery, and you'd plug your power cable into its USB port (not the Zero W's USB port), and power would be intelligently distributed between the battery and the Pi.

The problem with that approach is instead of using the Pi's USB power port, I have to use the PowerBoost's power USB port. My desire is, because the Pi has all its jacks secure in a row, I'd like to use them as is.

My thought is:

  1. CUT the connection between the Pi's USB power port and its power rails.
  2. INSTEAD re-route the Pi's USB power port to input to the PowerBoost.
  3. Connect the PowerBoost output to the Pi's PP1/PP6 (fairly typical).

My question is whether this is possible and the best way to go about it.

I think in the worst case, the USB power jack could be removed from the Pi and reconnected so it's not touching the solder pads, then +5V wired from it to the PowerBoost. Would it be a problem if the GND is shared though?

Or, are there some traces I can cut to remove the Pi's power from USB power jack, without desoldering the USB power jack? Is there anywhere I can get a board layout of the traces to see where they go?

Finally, has anyone done something like this before? I know it's easier to just use the PowerBoost separately, but I'd really like to re-use the Pi's power jack if at all possible, as it's a cleaner solution if it can be achieved.

  • AFAIK it will go through tiny traces on the board, and I havent found any schematics of which ones (though they will be the ones obviously leaving the connector). So it would likely be possible with precision equipment and magnifying glass! – Wilf Feb 11 '18 at 21:22
  • I should mention I really dug into where the traces are and never did manage to cut them. The Pi still works. I'm not sure how much deeper to cut. A board file (showing trace layout) would really come in handy. (Or an x-ray...) – mlepage Oct 7 '18 at 22:16
  • Why not simply solder or otherwise attach a micro usb male connector to the powerboost and connect it to the existing USB Power Jack? Then when the battery pack is removed, you can still use the USB power. You can cut the trace immediately at the connector with a sharp scalpel, but since as you point out, it only uses power line, you may as well just remove it, reuse it, or block it from being used (or break it). – crasic Feb 19 at 5:52
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Hmm, honestly, your question is a little difficult to understand (there are a lot of "bits", but I'm thinking:

You want to use your power supply plugged into the Pi0 power connector, without actually powering the Pi, but powering the 1000c instead. In other words, you want to plug the power supply into the Pi0's power connector, but use the UPS.

I'm not sure how your plan is "cleaner"?

Yes, the 0V can be common, definately!

Looking at my Pi0, there are no accessible tracks on the top or botton layer of the PCB.

BTW, I once unintentionally powered up my Pi0 via the USB host port.

          ******* HIGHLY NOT (!) RECOMMENDED *******

But... As you mentioned, you could desolder the micro-USB Power socket, run a 5V wire from the socket to the UPS (1000C - I want one!) and run a wire from the UPS's 5V2 output to the Pi0's 5V input power connector pad.

Put a tiny piece of electrical tape (Kapton tape or a thin piece of plastic would be better) between the connector and the solder pads.

Sort out the 0V somehow.

Solder and/or glue the connector shield back on.

But why do you want to use that single position on the Pi0 to power the UPS so desperately???

It is too risky, IMO. PLEASE don't attemp it!!!

          ******* HIGHLY NOT (!) RECOMMENDED *******
  • Simply, the reason is to re-use the form factor of the row of connections of the Pi in another larger case. It's true I could try to put the USB port for the UPS elsewhere, if there was room, but there isn't, and even then I'd have to prohibit the user from using the Pi's USB. – mlepage Oct 7 '18 at 22:15
  • Let us know how you go, please. – electron1979 Oct 7 '18 at 22:56

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