Series and Parallel

When connecting 2 cells of a battery, they can be wired in either series or parallel. When 2 calls are wired in series, the voltage of a battery is doubled. When wired in parallel, the amp hours and discharge rating of the battery are doubled. For example, lets say you had two cells that were each 1V, 1Ah and had a discharge rate of 1A. Wired in series, the battery the two cells form would have 2V, 1Ah and a discharge rate of 1A. Wired in parallel it would have 1V, 2Ah and a discharge rate of 2A.

Lithium ion packs will often be seen in configurations with varying cells in series and parallel, a commonly used notation is XSYP where X is the number of cells in series and Y is the number of cells in parallel. For example, a 10S4P would have 10 cells in series, with 4 in parallel for a total of 40 cells.