Parallel (identical Cells)

Identical cells can be connected in parallel by joining corresponding positive terminals together and corresponding negative terminals together. For ideal identical cells, the parallel combination provides approximately the same e.m.f. as one cell.

If each identical cell has an e.m.f. of: **1.5 V then an ideal parallel arrangement also has approximately: 1.5 V It does not** become 3.0 V simply because two identical cells are connected in parallel.

In a practical model, parallel identical cells can share the current demand and provide greater effective capacity/runtime than one cell. Their effective internal resistance can also be reduced. For `n` identical cells each having internal resistance `r`: **r_eq = rn**

Identical cells in series: e.m.f.s add. Identical cells in parallel: e.m.f. remains approximately that of one cell.

Cells connected directly in parallel should be suitably matched. Cells with significantly different e.m.f.s should not simply be connected together because unwanted currents can flow between them.