With my 7th Raspberry Pi I finally ventured into mobile space so to speak. While all my other applications so far were of stationary nature and power sockets were always close by, I had to use a mobile power source, i.e. a battery this time to keep the Pi running while it was in my backpack. Powering a Raspi from a battery that I normally use for recharging phones while on the move is straight forward as Raspberries use the same USB connector for power as most smartphones. No extras required, I just connected the 3000 mAh battery into the Raspi and it kept it running for around 4 hours. I've put a picture of the setup on the left of this post so you can get an idea of the battery size required to keep the Pi running for a couple of hours.