Whining... I wish that there was a way to

[slothead]

to know how much of a charge was on the range extender without turning EVERYTHING on.

 

[MapMaker53]

Add to that I wish it would charge faster.

 

[CityZen]

You could get a USB booster battery pack. You can get one of those with multiple LEDs that indicate the charge level.
Then just plug your extender into that pack, and don't worry about the extender's battery level.