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Powering raspberry pi 3b+ or 4 from the HAT/BONNET
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Powering raspberry pi 3b+ or 4 from the HAT/BONNET

by Riffnshred on Mon Dec 16, 2019 9:15 pm

Sorry if this has been a subject on the forum at this point but I can't find anything that answers my question.

I see on the Led matrix HAT tutorial that it is "optional but suggested" to power the raspberry pi using its own power supply. I was wondering what are the downside or risk to power the Pi from the HAT itself? If I use a more powerful power supply for the whole thing, would that cover the Pi?

Cheers

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Re: Powering raspberry pi 3b+ or 4 from the HAT/BONNET

by dastels on Mon Dec 16, 2019 11:16 pm

You can supply the Pi via the 5v pins on the GPIO header. The main thing is to supply enough current for the Pi's use. The one gotcha is whether the connections/traces are up to carrying that much current. Some hats, like the Crickit are designed for this. Not all are.

Dave

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Re: Powering raspberry pi 3b+ or 4 from the HAT/BONNET

by Riffnshred on Tue Dec 17, 2019 3:14 pm

I see. So I imagine something like the Pi zero should be just fine as it pulls about half what the Pi 3b+ needs at stress levels ?

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Re: Powering raspberry pi 3b+ or 4 from the HAT/BONNET

by dastels on Tue Dec 17, 2019 3:19 pm

Exactly. Just be sure your supply can provide plenty of current for everything.

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Re: Powering raspberry pi 3b+ or 4 from the HAT/BONNET

by alphanumeric on Wed Dec 18, 2019 6:03 am

The other thing that happens when you power the Pi via the GPIO +5V pin is you bypass the poly fuse on the Pi. If it has one that is. The Pi zero doesn't have one and I don't think the 4B has one either. That doesn't stop me from doing it though, it can be very convenient to go that route to save cable clutter.

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Re: Powering raspberry pi 3b+ or 4 from the HAT/BONNET

by dastels on Wed Dec 18, 2019 11:15 am

This approach let me use my Pi4 with a 5v4A power pack until I got a USB-C cable.

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Re: Powering raspberry pi 3b+ or 4 from the HAT/BONNET

by alphanumeric on Wed Dec 18, 2019 2:06 pm

I have a couple of setups where my powerboost feeds power to my Pi via the 5V GPIO pin. One of those uses a 5V 4A power pack with a barrel connector. Lots of different ways to do things, if you have a mind to.

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Please be positive and constructive with your questions and comments.