To obtain maximum Electromotive force (EMF), you should connect the batteries in

Series

Cells in Series connection.In series, cells are joined end to end so that the same current flows through each cell. In case if the cells are connected in series the emf of the battery connected to the sum of the emf of the individual cell,If E is the overall emf of the battery combined with n number cells and E1, E2,Em is the EMFs of individual cell.

Then   

E= E1+E2++Em.

the plateau is likely to turn into a desert do to corrosion.