Hey guys, I am looking at this charger and was wondering how big of a power supply I will need any input . I just want a real reliable system.

http://www.amainhobbies.com/product_...S-20A-400W-x-2

Right now i have a hitec x4 ac charger. The batteries I use are. 2s 7200mah and 4s 6500mah so I'd be charging at 7.2 and 6.5 amps