Now that I have a somewhat powerful charging system, 10 and 20 amps, 550 watts, I decided to mess around with higher charge rates. I have 6500 and 7600 2s batteries. So I did the math and 6500 @1.5c is 9750 or 10 amps, and 7600 @1.5c is 11400 or 12 amps. Needless to say the batteries charged very well. I added two lines to my computer power supply so I could hook up two chargers. I am very satisfied with this system, and how fast I was able to charge four batteries.