So the Pi works needs at least 0.8 amps and it can draw safely <= 2 amps?
Another question => at which voltage below 5 volts dies the Pi turn off? Thanks!

I eventually found an even better solution, which has a capacity of 15 ah, delivers 3.1 amp @ 5 volts and also works via micro-USB. Would this work with 3.1 amps over micro-USB (does the Pi withstand the current?) and since 2 amps is actually recommended, do you think it would even be possible to at...

But I can boot it, if I plug the battery in at the micro USB port, right? and if yes what's the reason, that it does not work via USB B, is there a diode or something in it, which only allows current out? Thanks : )/

Hello, I´ve decided to buy a Raspberry Pi B+ and I want to use it mobile, so for this purpose I want to use a 5 volts, 2.5 amps, 5000 mAh battery pack (http://www.amazon.de/EasyAcc-Schnelladefunktion-Eingebautem-Smatphones-Lautsprecher/dp/B00EK3UHS8/ref=sr_1_2?s=automotive&ie=UTF8&qid=1421634233&sr=...