I've done some research and one of the perks I've found to lithium ion batteries is apparently they can be charged extremely fast especially with multiple batteries. Basically, I was just wondering... let's say you have 1000ah of lithium ion batteries (5x200ah). The batteries are drained down to 200ah (20%). If you put 400 amps into them steady (let's say exactly 400 amps current), around how long would they take to charge? I know amps are not the same as "amp hours". But could one assume it would take around 2 hours, or is it impossible to know?