kdand919
Posts: 10
Joined: Wed Mar 11, 2015 2:40 am

5V GPIO Max Current

Wed Mar 25, 2015 7:19 pm

Hey everyone,

I am trying to power some neopixels with the raspberry pi and have a quick question about the maximum current permitted through the 5V pin. I keep coming across the following statement:

"maximum permitted current draw from the 5v pin is the USB input current (usually 1A) minus any current draw from the rest of the board."

So if I have a 2 amp usb power supply and I have a raspberry pi B using 700mA then will I be able to safely pull the remaining 1.3 amps with the 5V pin? what is this maximum current draw allowed this way? what about when using the various models (B, B+, 2) is there any variations?

Thanks,
Kyle

User avatar
DougieLawson
Posts: 36865
Joined: Sun Jun 16, 2013 11:19 pm
Location: Basingstoke, UK
Contact: Website Twitter

Re: 5V GPIO Max Current

Wed Mar 25, 2015 7:25 pm

That's mostly going to be mostly true for most cases with most models of Raspberry Pi. YMMV.

The 700mA draw for a model B board is measured with it running hard, but it assumes you have nothing in the USB ports.
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.

kdand919
Posts: 10
Joined: Wed Mar 11, 2015 2:40 am

Re: 5V GPIO Max Current

Wed Mar 25, 2015 7:40 pm

so what kind of maximum current can I draw through the 5V GPIO then? If I have a 5V 5A power supply will I be able to pull the remaining 4.3 amps through the pin to power the LED's? I won't be getting anywhere near this but I would like to know the limits so I don't push them.

Thanks again!

User avatar
joan
Posts: 14588
Joined: Thu Jul 05, 2012 5:09 pm
Location: UK

Re: 5V GPIO Max Current

Wed Mar 25, 2015 7:49 pm

I think the early model Pis have a 1amp polyfuse at the microUSB.

I think the A+/B+/Pi2 models have a 2amp polyfuse at the microUSB.

So if you power via the microUSB those are the limits. If you need more power then feed in through the expansion header ground and 5V pins.

User avatar
DougieLawson
Posts: 36865
Joined: Sun Jun 16, 2013 11:19 pm
Location: Basingstoke, UK
Contact: Website Twitter

Re: 5V GPIO Max Current

Wed Mar 25, 2015 7:50 pm

It depends. The spec says 2A at most. The thing you've got to avoid is drawing so much current from your power supply that it drops the voltage below 4V85 at which point you RPi will be struggling to stay alive.
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.

kdand919
Posts: 10
Joined: Wed Mar 11, 2015 2:40 am

Re: 5V GPIO Max Current

Thu Mar 26, 2015 12:36 am

Perfect thanks guys! The 2 amp poly fuse max was the answer I was looking for. I figured the raspberry pi B would be limited to 1 amp, but I have my B+ powering a hard drive which uses about 1 amp by itself and didn't know where the limits were.

Thanks again,
Kyle

Return to “Interfacing (DSI, CSI, I2C, etc.)”