When testing cables, my wife and I have 20,000mAh batteries. Both were discharged to 0, one was replaced with the cable provided and the other was charged with these cables. After 1 hour the standard cable was charged to 20%, the other to 35% with these cables. After 3 hours the standard cable charged the battery to 50% and these cables to 100%.2 A few hours later their standard cable package was finally at 100%. With these cables, my phone itself went from 3% to 35% in about 15 minutes. A standard cable charges my phone about 20%. With these cables and the speed at which they deliver power, I STRONGLY recommend that you unplug the cable as soon as your phone is charged.