For my testing I used both my Samsung Note 3 and my Wife’s iPhone 5c and I fully discharged / recharged the EnerG 4 times to get my results. I have to say I was very impressed. I charged both phones from around 10% to full charge and still had some life left in my Luxa2 EnerG 6600mAh version. So much so that I used it to charge my Note 3 for a 2nd time and got around a 50% charge out of it. That sounds good if you ask me but what sounds even better is when we do the math:
Note 3 Battery Capacity = 3200 mAh
90% capacity = 2880 mAh ( This is how many mAh that the EnerG charged)
50% capacity = 1600 mAh
1600 + 2880 = 4480 maH which is the total charge the EnerG gave my Note 3 of my testing period.
Iphone 5c Battery Capacity = 1510mAh
90% capacity = 1359 mAh which is the total charge the EnerG gave my Wife’s iPhone 5c over my testing period.
1359 + 4480 = 5839 mAh !!!
That means the Luxa2 EnerG 6600 mAh had an output of around 5839 mAh which is close to around 90% of advertised capacity. I am no professional but this seems very good to me. A loss of only 10% of the overall capacity is something I can surely live with and is expected, especially from a rechargeable battery.
Please note these are my own findings and may differ from those of others. It is also worth noting that over time the EnerG will lose performance but this is expected and will happen to any product of this nature.