flyingmonkey, FHHuber brings up some valid points. I have yet to have any problems with my 9C,hitec 7x or my skysport trainer box when fast charging. The diode can be a problem though. When I fast charge I never go above 1C, at home I use a reworked computer power supply with the fan blowing across the charger and radio(back plate removed).At the field if I need to fast charge I still keep it at 1C and just remove the back plate on the trans (no fan) NEVER take it up to 2amps and try a fast charge, if you batts are 600/700mah then use the .6amp setting...going a little beyond 1C can be done but it's risky and shortens battery life

John