What amp do you charge a 650 mAh battery at? It says it can charge at 3C1C would be 1/1000th of the mAh rating so a 5000mAh battery would be 5A. 5000/1000=5.
6000mAh = 6A, 3300mAh = 3.3A etc.
So a 3C rate on a 5000mAh battery would be 15A. 5000/1000=5 and 5x3=15.
Hope this helps.