Zoom H4n – Battery Problem

We all know the Problem with portable devices… the Battery are always empty and no socket is near your place because your are in the field or just in a Studio or big room without an extension cable and the wall is too far away.
This Problem is more or less noticeable on mobile devices, but i made the experience that this Problem is most likely with devices that are necessary for your job or this day
So it was with my Zoom H4n Portable Recorder, always the battery was empty and my NIMH-Batteries are not always with me or in the mess of my bags i do not always know which of my dozen battery a fully charged.
So what can we do about that?
Thankfully Zoom has an Charging port build into the the Recorder.
It needs DC5V and 1A of Power… so since Smartphones and Tablets are in the field with the same kind of Problem (Big Screens and small batteries) more and more so called Power Banks for Charging devices are available.
I bought one of them – The XTPower MP 10000
It is an Normal Powerbank but with an DC Output (which is not needed for this trick) but with this Powerbank comes a need little Cable (which is also available on ebay or Amazon)
you can PlugIn it directly into the Zoom and it runs for much longer, how much? Not tested yet but 10mAh should be enough for one Day on the field.