I want to make my raspberry pi portable, is it safe to run it from battery's?
I want to make my raspberry pi portable, is it safe to run it from battery's?
Hello, I'm currently working on an Instructable and element14 article about making a Raspberry Pi PowerHAT. It will let you power your Raspberry Pi with batteries, safely. I'll share the links here, once I complete them.
First of all, by using the 5V GPIO pin you are bypassing the input fuse that is on the RPi. This means you have no protection in case of a short circuit, or reverse voltage. If you do make an error, a lot of current (depending on how much you power supply can provide) can flow through your Pi and can damage it. You are also bypassing a high-efficiency diode circuit, so you are basically without any protection. I've included a schematic of the power management circuit for a Raspberry Pi Model B+, below.
Despite all these cons, it's still possible to power the Pi through the pins, with a simple circuit. First off, a regulated 5V power source has to be inputted to the 5V and ground GPIO pins. Most power adapters won't output a regulated voltage (unless stated otherwise on them) so you would also need to use some voltage regulator circuit. Lastly, there are a few capacitors used to smooth the voltage, which makes power more stable.
To power the Pi, you will need to have a regulation circuit, or use a regulated power supply. Then, just add a schottky diode on the input, and maybe a resettable fuse. I hope this helps, and I'll try to provide a schematic of said described circuit.
