How to Use the Battery Series/Parallel Calculator
When you wire identical battery cells together to build a pack, series and parallel connections have very different effects. Wiring cells in series adds up their voltage while capacity (Ah) stays the same as a single cell. Wiring cells in parallel adds up capacity while voltage stays the same as a single cell.
Most real-world battery packs use both at once, in an SxP configuration. For example, two 12V 100Ah deep-cycle batteries wired in series and then that pair duplicated in parallel (2S2P) gives you 24V at 200Ah — about 4,800Wh total.
This calculator takes your cell's voltage and capacity along with the series and parallel counts, then calculates the pack's total voltage, capacity, and energy in watt-hours. When building a real pack, always use cells from the same batch with matching condition, and add a battery management system (BMS) or fuse protection where applicable.
Frequently Asked Questions
Connecting cells in series adds up voltage while capacity (Ah) stays the same as a single cell. Connecting cells in parallel adds up capacity (Ah) while voltage stays the same as a single cell.
Yes — the common approach is to group identical cells in series first, then connect those series groups in parallel (an SxP configuration). Always use cells of the same specification and condition, since mixing different cells can shorten pack life and create a safety risk.