Mathematically OK, capacity indication is deceptive

With a built-in rechargeable battery with 3.6V nominal results calculated a total capacity of 3.6V 6000mAh * = 21,6Wh.

This 21,6Wh be issued with an output voltage of 5V, So has the "virtual battery" a charge of 21,6Wh / 5V = 4320mAh.

Since the built-in voltage transformers have a typical efficiency of 85%, the actual charge reduced to 4320mAh * 0.85 = 3672mAh.

The correct statement would have to be called "Power Bank with 3672mAh @ 5V".

I have unloaded the Power Bank on a ELV Battery Tester with 1500mA. The Power Bank has kept exactly 2.5 hours which mathematically then results in a charge of 3750mAh.

Here agrees exceptional cases even match the theoretical calculation with the practical.

So depending on the efficiency of the charging electronics of your phones, the Power Bank can charge a Durschnittshandy about two times.

The Power Bank holds exactly what it promises.