Among the 10,000 mAh power banks, a Varta model with wireless charging wins the test, while Xiaomi convinces with high performance and short charging time among the 20,000 mAh power banks. If you want to buy a really powerful power bank, it's best to go for the Anker 737 - it charges in record time, but is quite expensive...

In our test, we measured a real charging capacity of 73 percent for the Anker PowerCore Essential 20000 - very good! An extra feature is the so-called trickle charge: If you press the button longer (or alternatively twice), a charging mode is activated at the maximum speed of the device to be charged.