Charge current for a 8000 mah lipo battery?
You should charge batteries always in accord with manufacturer's specifications. Usually they rate the battery for "normal charge" (~0.2 C), and for "fast charge" (at 0.5 or 1.C rate). Charging Li-Po batteries at lower current won't damage anything, it will only increase its current capacity for a bit relative to it's nominal capacity. Always refer to real specifications, not what you read on Internet. 

BTW, there are Lithium-based batteries that are designed to be charged at 3C or even 5C rate, which is usually displayed on its label.