phase
Posts: 54
Joined: Thu Jun 30, 2016 3:05 am

power rpi-4 via the 40 pin header

Thu Aug 08, 2019 8:09 am

how do i go about powering the rpi-4 via the header pins..
does powering the board in this manner bypass any circuitry at all..???
.if somebody could point me to a thread or if it`s in a sticky i cannot find it..thanks...
Last edited by phase on Thu Aug 08, 2019 8:44 am, edited 1 time in total.

User avatar
joan
Posts: 14593
Joined: Thu Jul 05, 2012 5:09 pm
Location: UK

Re: power rpi-4 via extension header

Thu Aug 08, 2019 8:36 am

You can't power the Pi via the GPIO. You will destroy the Pi.

You can power the Pi via the 5V and ground pins on the extension header.

Code: Select all

https://pinout.xyz/

phase
Posts: 54
Joined: Thu Jun 30, 2016 3:05 am

Re: power rpi-4 via the 40 pin header

Thu Aug 08, 2019 8:46 am

thank you ..ok i will do it ,,i fixed my question..

User avatar
davidcoton
Posts: 4421
Joined: Mon Sep 01, 2014 2:37 pm
Location: Cambridge, UK

Re: power rpi-4 via the 40 pin header

Thu Aug 08, 2019 8:52 am

The Pi4 appears not to have a polyfuse, so there is no protection to bypass. There is still overvoltage/reverse polarity protection, so you should consider providing your own polyfuse between supply and Pi.
Signature retired

phase
Posts: 54
Joined: Thu Jun 30, 2016 3:05 am

Re: power rpi-4 via the 40 pin header

Thu Aug 08, 2019 9:29 am

would a 6.3 volt zenner to gnd be ok or a 5.1 and an in4004 in series to give 5.7 volts to gnd using 1 watt devices and an inline 3.15 amp fuse..
i dont know where i could get a 6 volt polyfuse from..??...or 5 volt for that matter

User avatar
Burngate
Posts: 6156
Joined: Thu Sep 29, 2011 4:34 pm
Location: Berkshire UK Tralfamadore
Contact: Website

Re: power rpi-4 via the 40 pin header

Thu Aug 08, 2019 9:35 am

There's a SMBJ - effectively a zener, etc. - on board, so you won't gain by providing your own.

Davidcotton is suggesting you provide a fuse that can blow when you trigger the SMBJ by doing something wrong.

Polyfuses can handle 6v and upwards. You need to choose one that can handle the full current that the Pi will take, but will blow at the higher current that the SMBJ will take when triggered, preferably before the SMBJ dies.

User avatar
rpdom
Posts: 15929
Joined: Sun May 06, 2012 5:17 am
Location: Chelmsford, Essex, UK

Re: power rpi-4 via the 40 pin header

Thu Aug 08, 2019 9:50 am

Fuses work on current (Amps) not voltage, even though they do frequently have maximum working voltage ratings for safety reasons.

phase
Posts: 54
Joined: Thu Jun 30, 2016 3:05 am

Re: power rpi-4 via the 40 pin header

Thu Aug 08, 2019 11:09 am

ok all the above taken into account ..can anybody tell me the max current that the rpi-4 can consume..pls..

User avatar
DougieLawson
Posts: 36900
Joined: Sun Jun 16, 2013 11:19 pm
Location: Basingstoke, UK
Contact: Website Twitter

Re: power rpi-4 via the 40 pin header

Thu Aug 08, 2019 11:10 am

phase wrote:
Thu Aug 08, 2019 11:09 am
ok all the above taken into account ..can anybody tell me the max current that the rpi-4 can consume..pls..
The official power supply is rated at 3000mA.
Note: Having anything humorous in your signature is completely banned on this forum. Wear a tin-foil hat and you'll get a ban.

Any DMs sent on Twitter will be answered next month.

This is a doctor free zone.

fruitoftheloom
Posts: 21394
Joined: Tue Mar 25, 2014 12:40 pm
Location: Delightful Dorset

Re: power rpi-4 via the 40 pin header

Thu Aug 08, 2019 11:27 am

phase wrote:
Thu Aug 08, 2019 11:09 am
ok all the above taken into account ..can anybody tell me the max current that the rpi-4 can consume..pls..

https://www.raspberrypi.org/documentati ... /#pi-power
Retired disgracefully.....
......to a more gentile life !

dzyner
Posts: 3
Joined: Wed Jan 15, 2020 4:04 pm

Re: power rpi-4 via the 40 pin header

Wed Jan 15, 2020 4:19 pm

Thought I'd post this here since it took me several hours to figure out, and a lot of folks saying it wasn't possible with Pi 4B to direct power through the 40 Pin GPIO. As you can see, assuming you've applied the proper Buck Converter to step down the power into the Pi (mine is connected from my 3D printer's power supply so I can power everything off with one switch), it certainly does work using pins 2 and 6. Whether or not this means my device "could" be damaged by doing this I do not know, but for now it is working fine so apparently they did not disable the ability to power the Pi via the GPIO connectors like many are saying.

Having said that, if you see something that I'm doing incorrectly or that could be very dangerous, please let me know since I am indeed a novice to the world of Raspberry Pi.
Attachments
2020-01-15_10-13-00.jpg
2020-01-15_10-13-00.jpg (226.51 KiB) Viewed 590 times

User avatar
rpdom
Posts: 15929
Joined: Sun May 06, 2012 5:17 am
Location: Chelmsford, Essex, UK

Re: power rpi-4 via the 40 pin header

Wed Jan 15, 2020 5:44 pm

dzyner wrote:
Wed Jan 15, 2020 4:19 pm
Thought I'd post this here since it took me several hours to figure out, and a lot of folks saying it wasn't possible with Pi 4B to direct power through the 40 Pin GPIO.
I don't know where you've seen that. It's common knowledge that the Pi 4B can be powered via the "GPIO" header if you supply a stable 5V with sufficient current to the correct pins. After all, that's how the official PoE HAT does it.

User avatar
davidcoton
Posts: 4421
Joined: Mon Sep 01, 2014 2:37 pm
Location: Cambridge, UK

Re: power rpi-4 via the 40 pin header

Wed Jan 15, 2020 10:34 pm

The only thing to be aware of is that the Pi's power protection relies on the PSU to limit the fault current to below 5A. So if you use a PSU/converter with a higher current capacity, you should include a 3A polyfuse (or equivalent protection).

Note that, unlike Pi1,2,3, the Pi4 does not have an on-board polyfuse even for the USB power input. So this advice applies whichever way your power gets on to the Pi4B.
Signature retired

dzyner
Posts: 3
Joined: Wed Jan 15, 2020 4:04 pm

Re: power rpi-4 via the 40 pin header

Thu Jan 16, 2020 12:02 am

rpdom wrote:
Wed Jan 15, 2020 5:44 pm
dzyner wrote:
Wed Jan 15, 2020 4:19 pm
Thought I'd post this here since it took me several hours to figure out, and a lot of folks saying it wasn't possible with Pi 4B to direct power through the 40 Pin GPIO.
I don't know where you've seen that. It's common knowledge that the Pi 4B can be powered via the "GPIO" header if you supply a stable 5V with sufficient current to the correct pins. After all, that's how the official PoE HAT does it.
In this very thread and others (link below to another topic on this forum). Second post in this thread specifically reads, "You can't power the Pi via the GPIO. You will destroy the Pi."

Here's another thread on this forum where it also mentions it isn't possible through the GPIO pins...

https://www.raspberrypi.org/forums/view ... p?t=248280

Perhaps I'm misunderstanding terms being noted in these posts, but regardless just thought I'd be helpful and point out that it does work.

drgeoff
Posts: 10109
Joined: Wed Jan 25, 2012 6:39 pm

Re: power rpi-4 via the 40 pin header

Thu Jan 16, 2020 12:20 am

dzyner wrote:
Thu Jan 16, 2020 12:02 am
rpdom wrote:
Wed Jan 15, 2020 5:44 pm
dzyner wrote:
Wed Jan 15, 2020 4:19 pm
Thought I'd post this here since it took me several hours to figure out, and a lot of folks saying it wasn't possible with Pi 4B to direct power through the 40 Pin GPIO.
I don't know where you've seen that. It's common knowledge that the Pi 4B can be powered via the "GPIO" header if you supply a stable 5V with sufficient current to the correct pins. After all, that's how the official PoE HAT does it.
In this very thread and others (link below to another topic on this forum). Second post in this thread specifically reads, "You can't power the Pi via the GPIO. You will destroy the Pi."

Here's another thread on this forum where it also mentions it isn't possible through the GPIO pins...

https://www.raspberrypi.org/forums/view ... p?t=248280

Perhaps I'm misunderstanding terms being noted in these posts, but regardless just thought I'd be helpful and point out that it does work.
GPIO means General Purpose Input/Output. The GPIOs are signal pins. You cannot power a RPi though signal pins.

The 40 pin GPIO header has both GPIOs and power pins. You can power any RPI through those power pins. On a RPi4B those pins are electrically commoned with the power input contacts of the USB-C socket.

hippy
Posts: 6544
Joined: Fri Sep 09, 2011 10:34 pm
Location: UK

Re: power rpi-4 via the 40 pin header

Thu Jan 16, 2020 2:12 am

dzyner wrote:
Thu Jan 16, 2020 12:02 am
rpdom wrote:
Wed Jan 15, 2020 5:44 pm
I don't know where you've seen that. It's common knowledge that the Pi 4B can be powered via the "GPIO" header if you supply a stable 5V with sufficient current to the correct pins. After all, that's how the official PoE HAT does it.
In this very thread and others ... Second post in this thread specifically reads, "You can't power the Pi via the GPIO. You will destroy the Pi."
That's because some people take "powering via GPIO", "powering via GPIO pins" to mean something other than "powering via the 0V and 5V pins which are present on the GPIO header".

I would normally assume that's what the poster meant, but others take it more literally.

dzyner
Posts: 3
Joined: Wed Jan 15, 2020 4:04 pm

Re: power rpi-4 via the 40 pin header

Thu Jan 16, 2020 5:14 pm

hippy wrote:
Thu Jan 16, 2020 2:12 am
That's because some people take "powering via GPIO", "powering via GPIO pins" to mean something other than "powering via the 0V and 5V pins which are present on the GPIO header".

I would normally assume that's what the poster meant, but others take it more literally.
I would agree with that, which is why it was so challenging for me to find the answer I needed, because I'm new (like many) to Pi and may not know the lingo yet. As a laymen, immediately when I read the OPs post in these threads I knew what they were asking. Yet the answer was consistently "not possible" or similar. I figured I'd do some newbies like me a favor and post my pics and explanation in case someone else finds this post (and they will) looking for the same answers - save them hours of research.

emma1997
Posts: 441
Joined: Sun Nov 08, 2015 7:00 pm
Location: New England (not that old one)

Re: power rpi-4 via the 40 pin header

Thu Jan 16, 2020 6:07 pm

What's ironic is it's quite common for beginners to accidentally power boards via IO bits. Current flows through reverse biased clamp diodes. Only those MCU with protection diode though which is not the case for Pi which does not have those.

Anyway language corrupts evolves so most people should know what "power via GPIO" means by now.

Return to “Beginners”