I'm going to test now time how long the device just like lying on your side, yet its cargo reserves: then you can always use it in an emergency.
Oh, one more thing: a bit silly, I find that the battery pack with a mini-USB needs to be recharged. Of course I had all the charging cable on iPhone changed (in the car) and therefore need now again more cable. It is also stupid that you can not come directly to the port of Apple because I connect my iPhone over to my car stereo.
Despite these drawbacks, I am still very satisfied with the purchase, because it is the best alternative if the iPhone is still just 20% of charge and it will be found in the near future no outlet. Strong buy recommendation.