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5V GPIO Max Current

Posted: Wed Mar 25, 2015 7:19 pm
by kdand919
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

Re: 5V GPIO Max Current

Posted: Wed Mar 25, 2015 7:25 pm
by DougieLawson
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.

Re: 5V GPIO Max Current

Posted: Wed Mar 25, 2015 7:40 pm
by kdand919
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!

Re: 5V GPIO Max Current

Posted: Wed Mar 25, 2015 7:49 pm
by joan
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.

Re: 5V GPIO Max Current

Posted: Wed Mar 25, 2015 7:50 pm
by DougieLawson
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.

Re: 5V GPIO Max Current

Posted: Thu Mar 26, 2015 12:36 am
by kdand919
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