When is a series-parallel arrangement of cells used?
A series arrangement of cells is used when you want to increase the voltage. If one cell = 1.5V, then six cells in series will give 9V. The parallel arrangement of cells s used when you want to lots of current:- if one cell= 1.5 V providing 0.5A, then six cells in parallel will still give 1.5V but 3A of current.