This Kitronik University Resource is a part of the BBC microbit partnership and explains the various options available for powering the BBC microbit. 
Powering the BBC microbit:
Learn how to:
- Power the BBC microbit.
JST Connector:
The most obvious common and convenient of powering the BBC microbit would be the on-board JST connector. A simple 2xAAA battery holder with JST connector can be used, ours has an M3 mounting hole in the centre which makes it perfect for use with our MI:pro protector case as seen in the image below. With this option the BBC microbit is powered and protected whilst still allowing access to the edge connector.
Micro USB:
The on-board micro USB connector whilst very commonly available is not a very portable solution, but could be of great use for projects where the BBC microbit stays in the same location.GPIO Pins:
There are some other options available for powering your BBC microbit, including the clearly marked 3V and 0V GPIO pins on the edge connector of the board.
Direct connection:
There are two pads on the back of the BBC microbit which can be powered with a direct connection. The 3V pin is the one closest to the edge connector as indicated in the image below.
MI:power board for the BBC microbit:
The MI:power board for the BBC microbit brings real portability to your projects. The stylish, lightweight PCB is designed to fit snugly against the BBC microbit and features a built in buzzer, on/off switch and 3V coin cell holder, making it an ideal option for powering the BBC microbit.
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6 comments
Billy
You might want to use a relay with the micro:bit as the controller to drive the motor using a separate 4.8V source as Mark has suggested. This one has a max of 2A so not sure if it fits your needs. https://www.kitronik.co.uk/46123-low-voltage-relay-for-microbit-solid-state.html
Mark Donnison
Hi Peter, if the micro:bit is connected to power sources that supply more power than the micro:bit is rated for the lifespan of the micro:bit can be significantly reduced. It is possible to kill your board entirely in this way. We would recommend using a different power source for the servo.
Peter
Hi, is it possible to Power the microbit with more than 3V? I Need 4,8V for an Servo!
Art MG
Great overview of options, and I love the MI:power. I guess you could hack up your own with a 3V button cell, non-conductive tape and wires. Of course you'd have to be careful to avoid shorting anything out with all that metal surface, and it does risk leaving sticky residue – maybe masking tape? Anyhow, I just ordered one as it's a much more stylish solution :) I also found this great research about micro:bit power consumption and voltage ranges – enjoy: http://www.reuk.co.uk/wordpress/microbit-power-consumption/
Mark Donnison
Thanks for the info Nigel and for the video link!
Nigel Tolley
Just so people know, the Microbit pulls about 10mA when running a basic script that scrolls the LEDs with a text message. (I just used the Blockly website thing and the built in text scroll function) I just ran one for an impressive 72 hours on a (parallel pair of) 18650's at 4.2V with a voltage drop board. I powered it through the two GPIO power passthroughs. Absolutely no issues, and it'll probably run for another week or 10 days before needing charged. Video: https://twitter.com/makebromyard/status/805499516648648708