Processing good endurance mediocre

I tested the unit on an iPhone 5 and reaches a maximum charge of 80% of the iPhone, which unfortunately is a poor value for the specified 2200 mAh.
If you subtract 20% power loss for the conversion to 5V charging voltage at the microUSB port and the charging electronics in the phone, a full charge of an Iphone 5 should be easily accessible. The battery has almost Iphone5 of 1500 mAh.
Property me now an anchor Astro purchased Mini, which is more favorable, provided with 3000 mAh, and invite Iphone5 to 100% and then again to 20% can before it is empty. In terms of size it is comparable.