Hello,i'm new to forum.I have asus f556u laptop. its battery not charging.say replace the battery.battery Model no is C21N1509. (7.6v) (38Wh) i want to repair this battery.however i remove battery casing.i saw there are 2 battery cells in battery case.one of cell have 3.8v and other one 3.8v.those cells connecting to the controller circuit.i have extra two 3.8v battery cells.i remove old two cells and connect new two cells to the controller.but voltage did not out from the output pins in controller circuit.i saw a controller chip named BQ30Z55 on battery controller pcb.how can i inset properly...