Question: how to fix xbox 360 wireless controller battery pack?
Answer:  Insert Battery 1 + Side Down.
 Insert Battery 2 - Side Down.
 Insert 4 Pennies on top of/in-between 2 batteries.
 Make sure batteries and pennies are snug and securet.
 Cut 3 pieces of electrical tape (2 shorter, 1 longer)
 Put 2 pieces of shorter electrical tape over batteries horizontally.