Exploring alternate methods for providing DC power to Raspberry Pi

Pin header is cool, I've done it. I like to use 7.4V or 11.1V LiPos, and an adjustable buck power supply, fed into a diode , then to the Pi header pins.

The buck PS can be adjusted for 5V + whatever voltage drop you get across the blocking diode. 

I tend to overdo the battery size mA hr, if you just want to make it thru the track once , a baby size lipo, maybe  wire qty 2 150mAhr 3.7 V in series would do the trick. 

  https://www.etechnophiles.com/rpi-zero-2w-board-layout-pinout-specs-price/

The DC-DC converter chip doesnt seem to have  significant transient protections built in. 

robogary said:

Pin header is cool

how did you do this, what kind of jumper wires did you use, one pin or 2? a Pi 4 can draw 3A, so the connector should be suitable for that. 

The Chinese jumper wires from my junk box are certainly not.

thanks for the thorough test, anyway it is clear that you loose a lot of voltage over the Dupont jumpers.

Note that the official 3A Raspberry Pi power supply uses 18 AWG cable.

18 AWG would do the job for sure. I've had to make my own cables for wire sizes that big using Mate-N-Lock pins and hot glue as a homemade connector housing to keep pin separation & keep the sockets straight on the pins. It does look like an ugly hack job tho.  Please share if you find a nice solution for terminating 18 or 16 AWG wires into the GPIO header. 

I also considered the standard GPIO ribbon cable, usually at 28 AWG. The case against them is the users dont often feed 5V to the RPI , the pins are used to source 5V for sensor use.  The 40 pin connector tho allows for a good mechanical fit. I'll have to give them a look too, do more measurements to check on voltage drop using multiple conductors in parallel, 2 for 5V and 2 for GND, on both the GPIO ribbon.

I also need to the load measurements while the RPI is running code, for sure that also has impact.

At the end, its mostly curiosity, a bigger wire size ultimately the simple answer, as long as it is mechanically stable and has some covering that keeps pins from shorting together. 

Some of the smaller boards like Zero and Pico can likely get by with a smaller 5V feeder wire size. 

In the past, if larger gauge wire was used, I would solder the wire to a 2.54 pin. You can crimp it but it can make a mess of the insulation on the wire depending on how thick it is. I then heat shrink to protect the pin. It has worked for me and since I don't have another solution, I will use it again.. This will be the first power connection I have done using this method. I have always managed to make the PS work. This project doesn't afford me a PS.

these connectors are 1A per pin, so with two 5V input pins you have 2A max.

I would propose to buy an official raspberry pi 4 power supply, cut the wire with the cable and throw away the power supply.

They are really cheap, price is comparable to a bare cable:

Buy Now

I was thinking the same. But colporteur wrote in the first post that there's no room for the USB connector in his design.

ok, you are right, forgot about that, I was more thinking for a solution for my own project 

On the other hand he is not using a Pi 4, so in that case it could work with proper pin headers and wiring.

much appreciate the input just the same.

Found these adapter cables on Amazon, sez 16 AWG, I have my doubts on that .....but here is a link to have a look https://www.amazon.com/Jienk-Terminal-Connector-Extension-Screwdriver/dp/B096RQNN8C/ref=sr_1_3?crid=1R8PJRO6AT2FN&keywords=Screw%2BTerminal%2BBlock%2BConnector%2Bto%2BUSB%2BC&qid=1649344174&s=electronics&sprefix=screw%2Bterminal%2Bblock%2Bconnector%2Bto%2Busb%2Bc%2Celectronics%2C132&sr=1-3&th=1

Another option to backfeeding GPIO with 5V. 

Looks interesting, much appreciated. I have been doing some reading about power supplies and their impacts on Pi4s. 16gauge is a step up from the typical 18 found in some power supplies. I have added it to an Amazon wish list for the next time I place an order.

Looks interesting, much appreciated. I have been doing some reading about power supplies and their impacts on Pi4s. 16gauge is a step up from the typical 18 found in some power supplies. I have added it to an Amazon wish list for the next time I place an order.

The RPI4 uses the USB-C connector, the link is for that adapter. The RPi 3 uses a micro USB.   https://www.amazon.com/gp/product/B07PJYVH12/ref=ox_sc_act_title_2?smid=A3MDC9KUHU6B27&psc=1

There are a variety of these adapters depending on the USB type. 

I'm starting to really like the idea of powering a project this way. It makes it easy to unplug the upstream battery, interlocking & buck power supply, and plug in the AC power supply when doing the project development & debugging.