Battery Power over GPIO

#1

Has anyone got a solution for powering over GPIO please?

I read somewhere (but can’t find it again) that sending 5v to pins 2 and 4 is adequate.

I have a 7" touch screen which needs USB power from 2 ports, and a keyboard touchpad in another USB.

There is the A8 module also.

However I sent 5v over those pins and the power was on/off/on/off and then it gave up.

Any pointers here?

If someone can recommend a small circuit board that does a stepup from 3.7v battery to the power required for Rock5a that would be super handy.

Open to ideas. I’m trying to power currently with a 3.7v 10,000 mAh battery but as mentioned sending it 5v isn’t working here, I’m also using SeeedStudio Lipo Rider Plus but it’s not working.

#2

I have powered the Rock 5 Model B i have using 5v into the GPIO pins. It is currently operating in a remote part of Wyoming, powered vampirically from a 5V 200A power rail of some rather obscure equipment.

It does work, however it needs notable amounts of current, at least 5A* for a board populated with a wifi module and a fan, and using an existing uninterruptible power supply type solution for a Raspberry PI or even trying to power it from a USB power bank style system such as what the Rider appears to be, may be insufficient.

You will also need cabling noticeably thicker than the usual GPIO jumpers or the ones contained in USB cables. Think the wiring used for ATX power supply 8 pin GPU cables and you have a decent idea of what is needed.

Unfortunately solutions like this with a current above 3A tend to be rather uncommon, in my experience also.

*A 5v 5A power supply is what i used in the development stage. I haven’t measured or calculated current draw. Its not hard to determine why i would be unconcerned with that for my application.

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#3

thanks for the reply, your understanding is what i experienced. my volts were sitting ‘around 5v’ but fluctuating around all the time, even more so under stress. my step up was built to go to 5v± and well it didn’t do the job at all under any load and some times would not boot.

thanks for stating it needs slightly higher, i can worry about stepping down instead of up. cables makes more sense also being thicker to negate the fluctuations.

thanks for post. cleared my head. ultimately i gave up on the project due to software limits in my particular use.