This external battery delivers powerful Power, 12Ah should be there.
Suppose there are practically only 10Ah available so the refill pack is sufficient for a common smartphone for at least one charge cycle under mobile conditions.
However, it should not be not blinded by the lush capacity figures you look at. First, electrical energy (galvanic current) can not just transfer you, such as gasoline from the reserve can (full container is empty), but distribute balancing. If several batteries are connected together, then they are emptied in the same sense. Is in advance been more claims a battery, then feeds the fuller battery emptier the battery while maintaining the operation of the smartphone.
When a certain voltage is not reached, the smartphone should to protect the data itself, first switch to power saving mode (if any), then perform the power-down procedure under controlled conditions. With the additional battery the time will be extended, where the smartphone in full operation can be used.
The battery can provide both 2.1Ah, but also 1,0Ah available. In practice, the USB cable limit the current because the strands have a very small cross-section in the cable and cause a higher electrical resistance.
The battery is definitely more than in between for the hungry, but a joyful message weekend event it can not ensure the same.
It must be remembered that the battery can only be charged with 1,0Ah, ie an almost exhausted battery takes about 12 hours to get back provide the maximum capacity available again can.
The supplied USB cable can be used as a charging cable, as well as a power supplier for USB devices when you connect the cable the other way around.
This description is intended to be brought closer without producing an abstruse technical work for the average consumer in simple terms of dealing with the external power source.